Nelfinavir
Medically reviewed on March 25, 2018
Dosage Forms
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Tablet, Oral:
Viracept: 250 mg, 625 mg
Brand Names: U.S.
· Viracept
Pharmacologic Category
· Antiretroviral, Protease Inhibitor (Anti-HIV)
Pharmacology
Binds to the site of HIV-1 protease activity and inhibits cleavage of viral Gag-Pol polyprotein precursors into individual functional proteins required for infectious HIV. This results in the formation of immature, noninfectious viral particles.
Absorption
AUC is two- to threefold higher under fed conditions versus fasting; AUC is highly variable in pediatric patients due to increased clearance, problems with compliance, and inconsistent food intake with dosing.
Distribution
Vd: 2 to 7 L/kg
Metabolism
Hepatic via CYP2C19 and 3A4; major metabolite has activity comparable to parent drug
Excretion
Feces (98% to 99%, 78% as metabolites, 22% as unchanged drug); urine (1% to 2%)
Time to Peak
Serum: 2 to 4 hours
Half-Life Elimination
3.5 to 5 hours
Protein Binding
>98%
Special Populations: Hepatic Function Impairment
Cmax and AUC were increased 22% and 62%, respectively, in subjects with moderate hepatic impairment when compared with subjects with normal hepatic function. Patients with severe hepatic impairment were not studied.
Use: Labeled Indications
HIV-1 infection: In combination with other antiretroviral therapy in the treatment of HIV infection
Contraindications
Coadministration with drugs that are highly dependent on CYP3A for clearance and for which elevated or reduced plasma concentrations are associated with serious and/or life-threatening events or lead to reduced efficacy of nelfinavir (eg, alfuzosin, amiodarone, cisapride, ergot derivatives [eg, dihydroergotamine, ergonovine, ergotamine, methylergonovine], lovastatin, lurasidone, oral midazolam, pimozide, quinidine, rifampin, sildenafil [when used for the treatment of pulmonary hypertension], simvastatin, St John's wort, triazolam).
Canadian labeling: Additional contraindications (not in US labeling): Clinically significant hypersensitivity to nelfinavir or any component of the formulation; coadministration with midazolam (regardless of dosage form)
Dosing: Adult
HIV-1 infection, treatment: Oral: 750 mg 3 times daily or 1250 mg twice daily with meals in combination with other antiretroviral therapies. Note: The HHS Perinatal HIV Guidelines do not recommend the 3-times-daily dosing in pregnant women (HHS [perinatal] 2017).
Dosing: Geriatric
Refer to adult dosing.
Dosing: Pediatric
HIV-1 infection, treatment: Oral:
Children 2 to <13 years: Note: Pediatric guidelines recommend twice-daily dosing (HHS [pediatric] 2016).
Weight-directed dosing: 45 to 55 mg/kg twice daily (maximum dose: 1,250 mg/dose) or 25 to 35 mg/kg (maximum dose: 750 mg/dose) 3 times daily; daily doses >2,500 mg/day have not been studied in children.
Fixed dosing:
10 to <13 kg: 500 mg (2 tablets) twice daily or 250 mg (1 tablet) 3 times daily
13 to <19 kg: 750 mg (3 tablets) twice daily or 500 mg (2 tablets) 3 times daily
19 to <21 kg: 1000 mg (4 tablets) twice daily or 500 mg (2 tablets) 3 times daily
≥21 kg: 1000 to 1250 mg (4 to 5 tablets) twice daily or 750 mg (3 tablets) 3 times daily
Adolescents: Refer to adult dosing. Note: Some adolescent patients require doses higher than adults to achieve similar nelfinavir AUCs; consider the use of serum drug concentrations to guide optimal dosing (HHS [pediatric] 2016).
Dosing: Renal Impairment
There are no dosage adjustments provided in the manufacturer’s labeling (has not been studied). However, since <2% excreted in urine a dosage reduction would not be expected. Guidelines suggest that no dosage adjustment is necessary (HHS [adult] 2015).
Dosing: Hepatic Impairment
Mild impairment (Child-Pugh class A): No dosage adjustment necessary.
Moderate to severe impairment (Child-Pugh class B or C): Use not recommended.
Administration
Tablets: Administer with a meal. If unable to swallow tablets, may dissolve tablets in a small amount of water; mix cloudy liquid well and consume immediately. Rinse glass with water and administer rinse to ensure receiving full dose. Alternatively, the tablets may be crushed and mixed with a small amount of food; entire contents should be consumed immediately. Avoid mixing with acidic foods or juices as combination may result in a bitter taste (Viracept Canadian product monograph 2016).
Dietary Considerations
Should be taken as scheduled with a meal.
Storage
Store at room temperature of 15°C to 30°C (59°F to 86°F).
Drug Interactions
Abacavir: Protease Inhibitors may decrease the serum concentration of Abacavir. Monitor therapy
Abemaciclib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Abemaciclib. Management: In patients taking abemaciclib at a dose of 200 mg or 150 mg twice daily, reduce the dose to 100 mg twice daily when combined with strong CYP3A4 inhibitors. In patients taking abemaciclib 100 mg twice daily, decrease the dose to 50 mg twice daily. Consider therapy modification
Acalabrutinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Acalabrutinib.Avoid combination
Ado-Trastuzumab Emtansine: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Ado-Trastuzumab Emtansine. Specifically, strong CYP3A4 inhibitors may increase concentrations of the cytotoxic DM1 component. Avoid combination
Afatinib: Nelfinavir may increase the serum concentration of Afatinib. Management: Per US labeling: reduce afatinib by 10 mg if not tolerated. Per Canadian labeling: avoid combination if possible; if used, administer nelfinavir simultaneously with or after the dose of afatinib. Consider therapy modification
Alfuzosin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Alfuzosin. Avoid combination
Alfuzosin: Protease Inhibitors may increase the serum concentration of Alfuzosin. Avoid combination
Alitretinoin (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Alitretinoin (Systemic). Management: Consider reducing the alitretinoin dose to 10 mg when used together with strong CYP3A4 inhibitors. Monitor for increased alitretinoin effects/toxicities if combined with a strong CYP3A4 inhibitor. Consider therapy modification
Almotriptan: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Almotriptan. Management: Limit initial almotriptan adult dose to 6.25 mg and maximum adult dose to 12.5 mg/24-hrs when used with a strong CYP3A4 inhibitor. Avoid concurrent use in patients with impaired hepatic or renal function. Consider therapy modification
Alosetron: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Alosetron. Monitor therapy
ALPRAZolam: CYP3A4 Inhibitors (Strong) may increase the serum concentration of ALPRAZolam. Management: Consider using an alternative agent that is less likely to interact. If combined, monitor for increased therapeutic/toxic effects of alprazolam if combined with a strong CYP3A4 inhibitor.Consider therapy modification
Amiodarone: Nelfinavir may increase the serum concentration of Amiodarone. Avoid combination
AmLODIPine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of AmLODIPine.Monitor therapy
Antidiabetic Agents: Hyperglycemia-Associated Agents may diminish the therapeutic effect of Antidiabetic Agents. Monitor therapy
Apixaban: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Apixaban. Monitor therapy
Aprepitant: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Aprepitant. Avoid combination
ARIPiprazole: CYP3A4 Inhibitors (Strong) may increase the serum concentration of ARIPiprazole. Management: See full interaction monograph for details. Consider therapy modification
ARIPiprazole Lauroxil: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of ARIPiprazole Lauroxil. Management: Please refer to the full interaction monograph for details concerning the recommended dose adjustments. Consider therapy modification
Astemizole: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Astemizole. Avoid combination
Asunaprevir: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Asunaprevir. Avoid combination
AtorvaSTATin: Protease Inhibitors may increase the serum concentration of AtorvaSTATin. Management: See full monograph for recommended dose limits. Avoid atorvastatin with tipranavir/ritonavir. Consider therapy modification
Avanafil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Avanafil. Avoid combination
Axitinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Axitinib. Management: Avoid concurrent use of axitinib with any strong CYP3A inhibitor whenever possible. If a strong CYP3A inhibitor must be used with axitinib, a 50% axitinib dose reduction is recommended. Avoid combination
Azithromycin (Systemic): Nelfinavir may increase the serum concentration of Azithromycin (Systemic).Monitor therapy
Barnidipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Barnidipine. Avoid combination
Bedaquiline: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Bedaquiline. Management: Limit the duration of concomitant administration of bedaquiline with CYP3A4 inhibitors to no more than 14 days, unless the benefit of continued administration is judged to outweigh the possible risks. Monitor for toxic effects of bedaquiline. Consider therapy modification
Benperidol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Benperidol. Monitor therapy
Benzhydrocodone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Benzhydrocodone. Specifically, the concentration of hydrocodone may be increased. Monitor therapy
Bictegravir: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Bictegravir. Monitor therapy
Blonanserin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Blonanserin. Avoid combination
Boceprevir: May decrease the serum concentration of Protease Inhibitors. Protease Inhibitors may decrease the serum concentration of Boceprevir. Management: Some combinations are not recommended. See full drug interaction monograph for details. Consider therapy modification
Bortezomib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Bortezomib. Monitor therapy
Bosentan: Nelfinavir may increase the serum concentration of Bosentan. Bosentan may decrease the serum concentration of Nelfinavir. Management: Initiate bosentan at, or adjust bosentan dose to, 62.5 mg once daily or every other day (based on tolerability) in patients who receive nelfinavir. Additionally, monitor for possible reduced clinical response to nelfinavir. Consider therapy modification
Bosutinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Bosutinib. Avoid combination
Brentuximab Vedotin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Brentuximab Vedotin. Specifically, concentrations of the active monomethyl auristatin E (MMAE) component may be increased. Monitor therapy
Brexpiprazole: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Brexpiprazole. Management: Reduce brexpiprazole dose to 50% of usual with a strong CYP3A4 inhibitor; reduce to 25% of usual if used with both a moderate CYP3A4 inhibitor and a CYP2D6 inhibitor, or if a strong CYP3A4 inhibitor is used in a CYP2D6 poor metabolizer. Consider therapy modification
Brigatinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Brigatinib. Management: Avoid concurrent use of brigatinib with strong CYP3A4 inhibitors when possible. If combination cannot be avoided, reduce the brigatinib dose by approximately 50%, rounding to the nearest tablet strength (ie, from 180 mg to 90 mg, or from 90 mg to 60 mg). Consider therapy modification
Brinzolamide: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Brinzolamide.Monitor therapy
Bromocriptine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Bromocriptine.Avoid combination
Budesonide (Nasal): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Budesonide (Nasal). Monitor therapy
Budesonide (Oral Inhalation): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Budesonide (Oral Inhalation). Monitor therapy
Budesonide (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Budesonide (Systemic). Avoid combination
Budesonide (Topical): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Budesonide (Topical). Management: Per US prescribing information, avoid this combination. Canadian product labeling does not recommend strict avoidance. If combined, monitor for excessive glucocorticoid effects as budesonide exposure may be increased. Consider therapy modification
Buprenorphine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Buprenorphine.Monitor therapy
BusPIRone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of BusPIRone. Management: Limit the buspirone dose to 2.5 mg daily and monitor patients for increased buspirone effects/toxicities if combined with strong CYP3A4 inhibitors. Consider therapy modification
Cabazitaxel: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cabazitaxel. Management: Concurrent use of cabazitaxel with strong inhibitors of CYP3A4 should be avoided when possible. If such a combination must be used, consider a 25% reduction in the cabazitaxel dose.Consider therapy modification
Cabozantinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cabozantinib. Management: Avoid use of a strong CYP3A4 inhibitor with cabozantinib if possible. If combined, cabozantinib dose adjustments are recommended and vary based on the cabozantinib product used and the indication for use. See monograph for details. Consider therapy modification
Calcifediol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Calcifediol. Monitor therapy
Calcium Channel Blockers (Nondihydropyridine): Protease Inhibitors may decrease the metabolism of Calcium Channel Blockers (Nondihydropyridine). Increased serum concentrations of the calcium channel blocker may increase risk of AV nodal blockade. Management: Avoid concurrent use when possible. If used, monitor for CCB toxicity. The manufacturer of atazanavir recommends a 50% dose reduction for diltiazem be considered. Saquinavir, tipranavir, and darunavir/cobicistat use with bepridil is contraindicated. Consider therapy modification
Cannabidiol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cannabidiol.Monitor therapy
Cannabis: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cannabis. More specifically, tetrahydrocannabinol and cannabidiol serum concentrations may be increased. Monitor therapy
CarBAMazepine: May increase the metabolism of Protease Inhibitors. Protease Inhibitors may decrease the metabolism of CarBAMazepine. Consider therapy modification
Cariprazine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cariprazine. Management: Cariprazine dose reductions of 50% are required; specific recommended management varies slightly for those stable on cariprazine versus those just starting cariprazine. See prescribing information or full interaction monograph for details. Consider therapy modification
Ceritinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ceritinib. Management: If such combinations cannot be avoided, the ceritinib dose should be reduced by approximately one-third (to the nearest 150 mg). Resume the prior ceritinib dose after cessation of the strong CYP3A4 inhibitor. Avoid combination
Cilostazol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cilostazol. Management: Consider reducing the cilostazol dose to 50 mg twice daily in adult patients who are also receiving strong inhibitors of CYP3A4. Consider therapy modification
Cisapride: Protease Inhibitors may increase the serum concentration of Cisapride. This may result in QTc prolongation and malignant cardiac arrhythmias. Avoid combination
Clarithromycin: Protease Inhibitors may diminish the therapeutic effect of Clarithromycin. Specifically, certain protease inhibitors may decrease formation of the active 14-hydroxy-clarithromycin metabolite, which may negatively impact clarithromycin effectiveness vs. H. influenzae and other non-MAC infections. Protease Inhibitors may increase the serum concentration of Clarithromycin. Clarithromycin dose adjustment in renally impaired patients may be needed. Clarithromycin may increase the serum concentration of Protease Inhibitors. Management: Saquinavir is contraindicated with clarithromycin. Avoid clarithromycin adult doses over 1000 mg/day with a protease inhibitor. Further dose reductions may be needed with impaired renal function. Consider alternative antimicrobial for a non-MAC infection. Consider therapy modification
CloZAPine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of CloZAPine. Monitor therapy
CloZAPine: CYP1A2 Inducers may decrease the serum concentration of CloZAPine. Monitor therapy
Cobimetinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Cobimetinib. Avoid combination
Codeine: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Codeine. Monitor therapy
Colchicine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Colchicine. Management: Colchicine is contraindicated in patients with impaired renal or hepatic function who are also receiving a strong CYP3A4 inhibitor. In those with normal renal and hepatic function, reduce colchicine dose as directed. Consider therapy modification
Conivaptan: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Conivaptan. Avoid combination
Copanlisib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Copanlisib. Management: If concomitant use of copanlisib and strong CYP3A4 inhibitors cannot be avoided, reduce the copanlisib dose to 45 mg. Monitor patients for increased copanlisib effects/toxicities.Consider therapy modification
Corticosteroids (Orally Inhaled): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Corticosteroids (Orally Inhaled). Management: Orally inhaled fluticasone propionate with a strong CYP3A4 inhibitor is not recommended. Exceptions: Beclomethasone (Oral Inhalation); Triamcinolone (Systemic). Monitor therapy
Corticosteroids (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Corticosteroids (Systemic). Exceptions: MethylPREDNISolone; PrednisoLONE (Systemic); PredniSONE.Monitor therapy
Crizotinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Crizotinib. Avoid combination
Cyclophosphamide: Protease Inhibitors may enhance the adverse/toxic effect of Cyclophosphamide. Specifically, the incidences of neutropenia, infection, and mucositis may be increased. Monitor therapy
CycloSPORINE (Systemic): Protease Inhibitors may increase the serum concentration of CycloSPORINE (Systemic). CycloSPORINE (Systemic) may increase the serum concentration of Protease Inhibitors.Consider therapy modification
CycloSPORINE (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of CycloSPORINE (Systemic). Consider therapy modification
CYP2C19 Inducers (Strong): May increase the metabolism of CYP2C19 Substrates (High risk with Inducers). Management: Consider an alternative for one of the interacting drugs. Some combinations may be specifically contraindicated. Consult appropriate manufacturer labeling. Consider therapy modification
CYP3A4 Inducers (Moderate): May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Monitor therapy
CYP3A4 Inducers (Strong): May increase the metabolism of CYP3A4 Substrates (High risk with Inducers). Management: Consider an alternative for one of the interacting drugs. Some combinations may be specifically contraindicated. Consult appropriate manufacturer labeling. Consider therapy modification
CYP3A4 Substrates (High risk with Inhibitors): CYP3A4 Inhibitors (Strong) may decrease the metabolism of CYP3A4 Substrates (High risk with Inhibitors). Exceptions: Alitretinoin (Systemic); AmLODIPine; Benzhydrocodone; Buprenorphine; Gefitinib; HYDROcodone; Praziquantel; Telithromycin; Vinorelbine. Consider therapy modification
Dabrafenib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dabrafenib. Avoid combination
Daclatasvir: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Daclatasvir. Management: Decrease the daclatasvir dose to 30 mg once daily if combined with a strong CYP3A4 inhibitor. No dose adjustment is needed when daclatasvir is used with darunavir/cobicistat. Consider therapy modification
Dapoxetine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dapoxetine. Avoid combination
Dasatinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dasatinib. Management: This combination should be avoided; consider reducing dasatinib dose if a strong CYP3A4 inhibitor must be used. If using dasatinib 70 mg/day or 100 mg/day, consider reduction to 20 mg/day; if using dasatinib 140 mg/day, consider reduction to 40 mg/day. Consider therapy modification
Deferasirox: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers).Monitor therapy
Deflazacort: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Deflazacort. Management: Administer one third of the recommended deflazacort dose when used together with a strong or moderate CYP3A4 inhibitor. Consider therapy modification
Delamanid: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Delamanid. Management: Increase electrocardiogram (ECG) monitoring frequency if delamanid is combined with strong CYP3A4 inhibitors because the risk for QTc interval prolongation may be increased. Continue frequent ECG assessments throughout the full delamanid treatment period. Consider therapy modification
Delavirdine: Protease Inhibitors may decrease the serum concentration of Delavirdine. Delavirdine may increase the serum concentration of Protease Inhibitors. Consider therapy modification
Dexamethasone (Ophthalmic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dexamethasone (Ophthalmic). Monitor therapy
DOCEtaxel: CYP3A4 Inhibitors (Strong) may increase the serum concentration of DOCEtaxel. Management: Avoid the concomitant use of docetaxel and strong CYP3A4 inhibitors when possible. If combined use is unavoidable, consider a 50% docetaxel dose reduction and monitor for increased docetaxel toxicities. Consider therapy modification
Domperidone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Domperidone.Avoid combination
Doxercalciferol: CYP3A4 Inhibitors (Strong) may decrease serum concentrations of the active metabolite(s) of Doxercalciferol. Monitor therapy
DOXOrubicin (Conventional): CYP3A4 Inhibitors (Strong) may increase the serum concentration of DOXOrubicin (Conventional). Management: Seek alternatives to strong CYP3A4 inhibitors in patients treated with doxorubicin whenever possible. One U.S. manufacturer (Pfizer Inc.) recommends that these combinations be avoided. Consider therapy modification
Dronabinol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dronabinol. Monitor therapy
Dronedarone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dronedarone.Avoid combination
Drospirenone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Drospirenone. Management: Drospirenone use is contraindicated specifically when the strong CYP3A4 inhibitors atazanavir and cobicistat are administered concurrently. Caution should be used when drospirenone is coadministered with other strong CYP3A4 inhibitors. Consider therapy modification
Dutasteride: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Dutasteride. Monitor therapy
Eletriptan: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Eletriptan. Avoid combination
Eliglustat: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Eliglustat. Management: Use should be avoided under some circumstances. See full drug interaction monograph for details. Consider therapy modification
Enfuvirtide: Protease Inhibitors may increase the serum concentration of Enfuvirtide. Enfuvirtide may increase the serum concentration of Protease Inhibitors. Monitor therapy
Enzalutamide: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Management: Concurrent use of enzalutamide with CYP3A4 substrates that have a narrow therapeutic index should be avoided. Use of enzalutamide and any other CYP3A4 substrate should be performed with caution and close monitoring. Consider therapy modification
Enzalutamide: May decrease the serum concentration of CYP2C19 Substrates (High risk with Inducers). Conversely, concentrations of active metabolites may be increased for those drugs activated by CYP2C19. Management: Concurrent use of enzalutamide with CYP2C19 substrates that have a narrow therapeutic index should be avoided. Use of enzalutamide and any other CYP2C19 substrate should be performed with caution and close monitoring. Consider therapy modification
Eplerenone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Eplerenone. Avoid combination
Ergot Derivatives: Protease Inhibitors may increase the serum concentration of Ergot Derivatives.Exceptions: Cabergoline; Nicergoline; Pergolide. Avoid combination
Erlotinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Erlotinib. Management: Avoid use of this combination when possible. When the combination must be used, monitor the patient closely for the development of severe adverse reactions, and if such severe reactions occur, reduce the erlotinib dose (in 50 mg decrements). Consider therapy modification
Estazolam: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Estazolam. Monitor therapy
Estriol (Systemic): Nelfinavir may decrease the serum concentration of Estriol (Systemic). Monitor therapy
Estriol (Topical): Nelfinavir may decrease the serum concentration of Estriol (Topical). Monitor therapy
Estrogen Derivatives: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Estrogen Derivatives. Monitor therapy
Estrogen Derivatives (Contraceptive): Protease Inhibitors may decrease the serum concentration of Estrogen Derivatives (Contraceptive). Management: Use oral contraceptives containing at least 35mcg ethinyl estradiol with atazanavir/ritonavir, or no more than 30mcg in patients receiving atazanavir alone. Use of an alternative, non-hormonal contraceptive is recommended with other protease inhibitors. Consider therapy modification
Eszopiclone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Eszopiclone. Management: Limit the eszopiclone dose to 2 mg daily when combined with strong CYP3A4 inhibitors and monitor for increased eszopiclone effects and toxicities (eg, somnolence, drowsiness, CNS depression). Consider therapy modification
Etizolam: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Etizolam. Management: Consider use of lower etizolam doses when using this combination; specific recommendations concerning dose adjustment are not available. Monitor clinical response to the combination closely. Consider therapy modification
Etravirine: Protease Inhibitors may decrease the serum concentration of Etravirine. This effect is anticipated with darunavir, saquinavir, and lopinavir (with low-dose ritonavir). Etravirine may increase the serum concentration of Protease Inhibitors. This effect is anticipated with nelfinavir. Management: Low-dose ritonavir boosting must be used when any protease inhibitor is used with etravirine. Avoid use of etravirine in combination with atazanavir, fosamprenavir, full-dose ritonavir (600 mg twice daily, in adults), or tipranavir. Monitor therapy
Everolimus: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Everolimus. Avoid combination
Evogliptin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Evogliptin. Monitor therapy
FentaNYL: CYP3A4 Inhibitors (Strong) may increase the serum concentration of FentaNYL. Management: Monitor patients closely for several days following initiation of this combination, and adjust fentanyl dose as necessary. Consider therapy modification
Fesoterodine: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Fesoterodine. Management: Avoid fesoterodine doses greater than 4 mg daily in adult patients who are also receiving strong CYP3A4 inhibitors. Consider therapy modification
Flibanserin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Flibanserin. Avoid combination
Fluticasone (Nasal): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Fluticasone (Nasal). Avoid combination
Fluticasone (Oral Inhalation): CYP3A4 Inhibitors (Strong) may increase the serum concentration of Fluticasone (Oral Inhalation). Management: Use of orally inhaled fluticasone propionate with strong CYP3A4 inhibitors is not recommended. Use of orally inhaled fluticasone furoate with strong CYP3A4 inhibitors should be done with caution. Monitor patients using such a combination more closely.Consider therapy modification
Fosphenytoin: May decrease the serum concentration of Nelfinavir. Nelfinavir may decrease the serum concentration of Fosphenytoin. Monitor therapy
Fostamatinib: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Fostamatinib. Monitor therapy
Garlic: May decrease the serum concentration of Protease Inhibitors. Management: Concurrent use of garlic supplements with protease inhibitors is not recommended. If this combination is used, monitor closely for altered serum concentrations/effects of protease inhibitors, and particularly for signs/symptoms of therapeutic failure. Consider therapy modification
Gefitinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Gefitinib. Monitor therapy
GuanFACINE: CYP3A4 Inhibitors (Strong) may increase the serum concentration of GuanFACINE. Management: Reduce the guanfacine dose by 50% when initiating this combination. Consider therapy modification
Halofantrine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Halofantrine. Avoid combination
Histamine H2 Receptor Antagonists: May decrease the serum concentration of Nelfinavir. Concentrations of the active M8 metabolite may also be reduced. Monitor therapy
HYDROcodone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of HYDROcodone.Monitor therapy
HydrOXYzine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of HydrOXYzine. Management: This combination is specifically contraindicated in some non-U.S. labeling. Consider therapy modification
Ibrutinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ibrutinib. Management: Avoid concomitant use of ibrutinib and strong CYP3A4 inhibitors. If a strong CYP3A4 inhibitor must be used short-term (eg, anti-infectives for 7 days or less), interrupt ibrutinib therapy until the strong CYP3A4 inhibitor is discontinued. Avoid combination
Idelalisib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Idelalisib. Monitor therapy
Ifosfamide: CYP3A4 Inhibitors (Strong) may decrease serum concentrations of the active metabolite(s) of Ifosfamide. Monitor therapy
Iloperidone: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Iloperidone. Specifically, concentrations of the metabolites P88 and P95 may be increased. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Iloperidone. Management: Reduce iloperidone dose by half when administered with a strong CYP3A4 inhibitor. Consider therapy modification
Imatinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Imatinib. Monitor therapy
Imidafenacin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Imidafenacin.Monitor therapy
Irinotecan Products: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Irinotecan Products. Specifically, serum concentrations of SN-38 may be increased. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Irinotecan Products. Avoid combination
Isavuconazonium Sulfate: CYP3A4 Inhibitors (Strong) may increase serum concentrations of the active metabolite(s) of Isavuconazonium Sulfate. Specifically, CYP3A4 Inhibitors (Strong) may increase isavuconazole serum concentrations. Management: Combined use is considered contraindicated per US labeling. Lopinavir/ritonavir (and possibly other uses of ritonavir doses less than 400 mg every 12 hours) is treated as a possible exception to this contraindication despite strongly inhibiting CYP3A4.Avoid combination
Ivabradine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ivabradine. Avoid combination
Ivacaftor: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ivacaftor. Management: Ivacaftor dose reductions are required; consult full monograph content for specific age- and weight-based recommendations. Consider therapy modification
Ixabepilone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ixabepilone.Consider therapy modification
Lacosamide: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lacosamide.Monitor therapy
Lapatinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lapatinib. Management: If an overlap in therapy cannot be avoided, consider reducing lapatinib adult dose to 500 mg/day during, and within 1 week of completing, treatment with the strong CYP3A4 inhibitor.Avoid combination
Lercanidipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lercanidipine.Avoid combination
Levobupivacaine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Levobupivacaine. Monitor therapy
Levomilnacipran: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Levomilnacipran. Management: Do not exceed a maximum adult levomilnacipran dose of 80 mg/day in patients also receiving strong CYP3A4 inhibitors. Consider therapy modification
Lomitapide: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lomitapide. Avoid combination
Lopinavir: Nelfinavir may decrease the serum concentration of Lopinavir. Lopinavir may increase the serum concentration of Nelfinavir. Concentrations of the nelfinavir M8 metabolite may also be increased. Management: Avoid once daily use of lopinavir/ritonavir with nelfinavir. Avoid use of this combination in patients less than 6 months of age. See lopinavir/ritonavir prescribing information for recommended dose increases in other patients. Consider therapy modification
Lovastatin: Protease Inhibitors may increase the serum concentration of Lovastatin. Avoid combination
Lovastatin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lovastatin. Avoid combination
Lurasidone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Lurasidone. Avoid combination
Macitentan: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Macitentan. Avoid combination
Manidipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Manidipine. Management: Consider avoiding concomitant use of manidipine and strong CYP3A4 inhibitors. If combined, monitor closely for increased manidipine effects and toxicities. Manidipine dose reductions may be required. Consider therapy modification
Maraviroc: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Maraviroc. Management: Reduce the adult dose of maraviroc to 150 mg twice daily when used with a strong CYP3A4 inhibitor. Do not use maraviroc with strong CYP3A4 inhibitors in patients with Clcr less than 30 mL/min. Consider therapy modification
Meperidine: Protease Inhibitors may enhance the adverse/toxic effect of Meperidine. Protease Inhibitors may decrease the serum concentration of Meperidine. Concentrations of the toxic Normeperidine metabolite may be increased. Consider therapy modification
Methadone: Nelfinavir may decrease the serum concentration of Methadone. Monitor therapy
MethylPREDNISolone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of MethylPREDNISolone. Management: Consider methylprednisolone dose reduction in patients receiving strong CYP3A4 inhibitors and monitor for increased steroid related adverse effects. Consider therapy modification
Midazolam: Protease Inhibitors may increase the serum concentration of Midazolam. Management: Oral midazolam contraindicated with all protease inhibitors. IV midazolam contraindicated with fosamprenavir and nelfinavir; other protease inhibitors recommend caution, close monitoring, and consideration of lower IV midazolam doses with concurrent use. Avoid combination
Midostaurin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Midostaurin. Management: Seek alternatives to the concomitant use of midostaurin and strong CYP3A4 inhibitors if possible. If concomitant use cannot be avoided, monitor patients for increased risk of adverse reactions. Consider therapy modification
MiFEPRIStone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of MiFEPRIStone. Management: Limit mifepristone adult dose, when used for treatment of hyperglycemia in Cushing's syndrome, to a maximum of 600 mg/day when combined with a strong CYP3A4 inhibitor. Monitor for increased mifepristone toxicity regardless of dose or indication. Consider therapy modification
MiFEPRIStone: May enhance the QTc-prolonging effect of QTc-Prolonging Agents (Indeterminate Risk and Risk Modifying). Management: Though the drugs listed here have uncertain QT-prolonging effects, they all have some possible association with QT prolongation and should generally be avoided when possible. Consider therapy modification
Mirodenafil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Mirodenafil. Management: Consider using a lower dose of mirodenafil when used with strong CYP3A4 inhibitors. Monitor for increased mirodenafil effects/toxicities with the use of this combination. Consider therapy modification
Mitotane: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Management: Doses of CYP3A4 substrates may need to be adjusted substantially when used in patients being treated with mitotane. Consider therapy modification
Naldemedine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Naldemedine.Monitor therapy
Nalfurafine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Nalfurafine. Monitor therapy
Naloxegol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Naloxegol. Avoid combination
Nefazodone: Protease Inhibitors may increase the serum concentration of Nefazodone. Management: Consider alternatives to, or reduced doses of, nefazodone in patients treated with HIV protease inhibitors. Monitor patients receiving these combinations closely for toxic effects of nefazodone.Consider therapy modification
Neratinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Neratinib. Avoid combination
Nevirapine: May decrease serum concentrations of the active metabolite(s) of Nelfinavir. Nevirapine may decrease the serum concentration of Nelfinavir. Monitor therapy
Nilotinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Nilotinib. Management: Avoid when possible. If coadministration is necessary, decrease nilotinib dose to 300 mg once daily for patients with resistant or intolerant Ph+ CML or to 200 mg once daily for patients with newly diagnosed Ph+ CML in chronic phase. Consider therapy modification
NiMODipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of NiMODipine. Avoid combination
Nisoldipine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Nisoldipine. Avoid combination
Olaparib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Olaparib. Management: Avoid use of strong CYP3A4 inhibitors in patients being treated with olaparib, if possible. If such concurrent use cannot be avoided, the dose of olaparib should be reduced to 100 mg twice daily. Consider therapy modification
Orlistat: May decrease the serum concentration of Antiretroviral Agents. Monitor therapy
Ospemifene: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ospemifene.Monitor therapy
Oxybutynin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Oxybutynin. Monitor therapy
OxyCODONE: CYP3A4 Inhibitors (Strong) may enhance the adverse/toxic effect of OxyCODONE. CYP3A4 Inhibitors (Strong) may increase the serum concentration of OxyCODONE. Serum concentrations of the active metabolite oxymorphone may also be increased. Consider therapy modification
Palbociclib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Palbociclib. Avoid combination
Panobinostat: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Panobinostat. Management: Reduce the panobinostat dose to 10 mg when it must be used with a strong CYP3A4 inhibitor. Consider therapy modification
Parecoxib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Parecoxib. Monitor therapy
Paricalcitol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Paricalcitol. Monitor therapy
PAZOPanib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of PAZOPanib. Management: Avoid concurrent use of pazopanib with strong inhibitors of CYP3A4 whenever possible. If it is not possible to avoid such a combination, reduce pazopanib adult dose to 400 mg. Further dose reductions may also be required. Consider therapy modification
P-glycoprotein/ABCB1 Inhibitors: May increase the serum concentration of P-glycoprotein/ABCB1 Substrates. P-glycoprotein inhibitors may also enhance the distribution of p-glycoprotein substrates to specific cells/tissues/organs where p-glycoprotein is present in large amounts (e.g., brain, T-lymphocytes, testes, etc.). Monitor therapy
Phenytoin: Nelfinavir may decrease the serum concentration of Phenytoin. Phenytoin may decrease the serum concentration of Nelfinavir. Monitor therapy
Pimavanserin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Pimavanserin.Consider therapy modification
Pimecrolimus: CYP3A4 Inhibitors (Strong) may decrease the metabolism of Pimecrolimus. Monitor therapy
Pimozide: Protease Inhibitors may increase the serum concentration of Pimozide. Avoid combination
Pimozide: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Pimozide. Avoid combination
Piperaquine: CYP3A4 Inhibitors (Strong) may enhance the QTc-prolonging effect of Piperaquine. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Piperaquine. Management: Avoid the concomitant use of piperaquine and strong CYP3A4 inhibitors when possible. If this combination cannot be avoided, frequent ECG monitoring is recommended due to the increased risk for QTc prolongation. Consider therapy modification
Pitolisant: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Management: Combined use of pitolisant with a CYP3A4 substrate that has a narrow therapeutic index should be avoided. Other CYP3A4 substrates should be monitored more closely when used with pitolisant. Consider therapy modification
PONATinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of PONATinib. Management: Per ponatinib U.S. prescribing information, the adult starting dose of ponatinib should be reduced to 30 mg daily during treatment with any strong CYP3A4 inhibitor. Consider therapy modification
Pranlukast: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Pranlukast. Monitor therapy
Prasugrel: CYP3A4 Inhibitors (Strong) may decrease serum concentrations of the active metabolite(s) of Prasugrel. Monitor therapy
Pravastatin: Nelfinavir may decrease the serum concentration of Pravastatin. Monitor therapy
Praziquantel: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Praziquantel.Monitor therapy
PrednisoLONE (Systemic): CYP3A4 Inhibitors (Strong) may increase the serum concentration of PrednisoLONE (Systemic). Monitor therapy
PredniSONE: CYP3A4 Inhibitors (Strong) may increase the serum concentration of PredniSONE.Monitor therapy
Progestins (Contraceptive): Nelfinavir may decrease the serum concentration of Progestins (Contraceptive). Management: Use an alternative or additional method of contraception due to possibly decreased contraceptive effectiveness. Injected depot medroxyprogesterone acetate does not appear to participate in this interaction. Consider therapy modification
Propafenone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Propafenone.Monitor therapy
Protease Inhibitors: May increase the serum concentration of other Protease Inhibitors. Management: Atazanavir--indinavir combination contraindicated. Tipranavir/ritonavir or atazanavir/ritonavir not recommended with other protease inhibitors (PI). Darunavir/cobicistat not recommended with PI that require boosting.Other combos may require dose changes. Consider therapy modification
Proton Pump Inhibitors: May decrease serum concentrations of the active metabolite(s) of Nelfinavir. Proton Pump Inhibitors may decrease the serum concentration of Nelfinavir. Avoid combination
QTc-Prolonging Agents (Highest Risk): QTc-Prolonging Agents (Indeterminate Risk and Risk Modifying) may enhance the QTc-prolonging effect of QTc-Prolonging Agents (Highest Risk). Management: Avoid such combinations when possible. Use should be accompanied by close monitoring for evidence of QT prolongation or other alterations of cardiac rhythm. Consider therapy modification
QTc-Prolonging Agents (Moderate Risk): QTc-Prolonging Agents (Indeterminate Risk and Risk Modifying) may enhance the QTc-prolonging effect of QTc-Prolonging Agents (Moderate Risk).Monitor therapy
QUEtiapine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of QUEtiapine. Management: In quetiapine treated patients, reduce the quetiapine dose to one sixth of the regular dose following strong CYP3A4 inhibitor initiation. In patients receiving strong CYP3A4 inhibitors, initiate quetiapine at the lowest dose and up-titrate as needed. Consider therapy modification
QuiNIDine: Nelfinavir may increase the serum concentration of QuiNIDine. Avoid combination
Radotinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Radotinib. Avoid combination
Ramelteon: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ramelteon. Monitor therapy
Ranolazine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ranolazine. Avoid combination
Reboxetine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Reboxetine. Consider therapy modification
Red Yeast Rice: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Red Yeast Rice. Specifically, concentrations of lovastatin and related compounds found in Red Yeast Rice may be increased. Avoid combination
Regorafenib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Regorafenib. Avoid combination
Repaglinide: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Repaglinide. Management: The addition of a CYP2C8 inhibitor to this drug combination may substantially increase the magnitude of increase in repaglinide exposure. Monitor therapy
Retapamulin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Retapamulin. Management: Avoid this combination in patients less than 2 years old. No action is required in other populations. Monitor therapy
Ribociclib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ribociclib. Management: Avoid use of ribociclib with strong CYP3A4 inhibitors when possible; if combined use cannot be avoided, reduce ribociclib dose to 400 mg once daily. Consider therapy modification
Rifabutin: Nelfinavir may increase serum concentrations of the active metabolite(s) of Rifabutin. Rifabutin may decrease the serum concentration of Nelfinavir. Nelfinavir may increase the serum concentration of Rifabutin. Management: Nelfinavir US prescribing information recommends decreasing the usual rifabutin dose by at least 50% when used with nelfinavir. Additionally, the preferred dose of nelfinavir when used in combination with rifabutin is 1250 mg twice daily. Consider therapy modification
RifAMPin: May decrease the serum concentration of Nelfinavir. Avoid combination
Rilpivirine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Rilpivirine. Monitor therapy
Riociguat: Protease Inhibitors may increase the serum concentration of Riociguat. Management: Consider starting with a reduced riociguat dose of 0.5 mg three times a day (for adults). Patients receiving such a combination should also be monitored extra closely for signs or symptoms of hypotension. Consider therapy modification
RomiDEPsin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of RomiDEPsin.Monitor therapy
Rosuvastatin: Protease Inhibitors may increase the serum concentration of Rosuvastatin. Management: Start at the lowest rosuvastatin dose and monitor for toxicity. See full drug interaction monograph for details. Consider therapy modification
Rupatadine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Rupatadine. Avoid combination
Ruxolitinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ruxolitinib. Management: This combination should be avoided under some circumstances. See monograph for details. Consider therapy modification
Salmeterol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Salmeterol. Avoid combination
Sarilumab: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers).Monitor therapy
SAXagliptin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of SAXagliptin. Management: Saxagliptin U.S. product labeling recommends limiting saxagliptin adult dose to 2.5 mg/day when used with a strong CYP3A4 inhibitor. Monitor for increased saxagliptin levels/effects. A similar recommendation is not made in the Canadian product labeling. Consider therapy modification
Sildenafil: Protease Inhibitors may increase the serum concentration of Sildenafil. Management: Erectile dysfunction: sildenafil max = 25 mg/48 hrs with ritonavir, atazanavir, or darunavir; starting dose = 25 mg with other protease inhibitors (adult doses). Contraindicated if sildenafil being used for pulmonary arterial hypertension. Consider therapy modification
Sildenafil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Sildenafil. Management: Use of sildenafil for pulmonary hypertension should be avoided with strong CYP3A4 inhibitors. When used for erectile dysfunction, starting adult dose should be reduced to 25 mg. Maximum adult dose with ritonavir or cobicistat is 25 mg per 48 hours. Consider therapy modification
Silodosin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Silodosin. Avoid combination
Siltuximab: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers).Monitor therapy
Simeprevir: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Simeprevir. Avoid combination
Simeprevir: Protease Inhibitors may increase the serum concentration of Simeprevir. Simeprevir may increase the serum concentration of Protease Inhibitors. Avoid combination
Simvastatin: Protease Inhibitors may increase the serum concentration of Simvastatin. Avoid combination
Simvastatin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Simvastatin. Avoid combination
Sirolimus: Nelfinavir may increase the serum concentration of Sirolimus. Management: Carefully monitor the need for sirolimus dosage reductions when coadministered with nelfinavir. Sirolimus dosage reduction will probably be needed. Consider therapy modification
Sonidegib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Sonidegib. Avoid combination
SORAfenib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of SORAfenib. Monitor therapy
St John's Wort: May increase the metabolism of Protease Inhibitors. Avoid combination
SUFentanil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of SUFentanil. Management: If a strong CYP3A4 inhibitor is initiated in a patient on sufentanil, consider a sufentanil dose reduction and monitor for increased sufentanil effects and toxicities (eg, respiratory depression).Consider therapy modification
Suvorexant: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Suvorexant. Avoid combination
Tacrolimus (Systemic): Nelfinavir may increase the serum concentration of Tacrolimus (Systemic).Avoid combination
Tacrolimus (Topical): Protease Inhibitors may decrease the metabolism of Tacrolimus (Topical).Monitor therapy
Tadalafil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tadalafil. Management: Recommendations regarding use of tadalafil in patients also receiving strong CYP3A4 inhibitors may vary based on indication and/or international labeling. Consult appropriate product labeling. Consider therapy modification
Tamsulosin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tamsulosin. Avoid combination
Tasimelteon: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tasimelteon.Monitor therapy
Telithromycin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Telithromycin.Monitor therapy
Temsirolimus: Protease Inhibitors may enhance the adverse/toxic effect of Temsirolimus. Levels of sirolimus, the active metabolite, may be increased, likely due to inhibition of CYP-mediated metabolism. Consider therapy modification
Temsirolimus: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Temsirolimus. Management: Avoid concomitant use of temsirolimus and strong CYP3A4 inhibitors whenever possible. If combined, decrease temsirolimus dose to 12.5 mg per week and monitor patients for increased temsirolimus effects and toxicities. Consider therapy modification
Terfenadine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Terfenadine. Avoid combination
Tetrahydrocannabinol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tetrahydrocannabinol. Monitor therapy
Tezacaftor: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tezacaftor. Management: When combined with strong CYP3A4 inhibitors, tezacaftor/ivacaftor (100 mg/150 mg) should be administered in the morning, twice a week, approximately 3 to 4 days apart. No evening doses of ivacaftor (150 mg) alone should be administered. Consider therapy modification
Theophylline Derivatives: Protease Inhibitors may decrease the serum concentration of Theophylline Derivatives. Exceptions: Dyphylline. Monitor therapy
Ticagrelor: CYP3A4 Inhibitors (Strong) may decrease serum concentrations of the active metabolite(s) of Ticagrelor. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ticagrelor. Avoid combination
Tipranavir: May decrease the serum concentration of Protease Inhibitors. Avoid combination
Tocilizumab: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers).Monitor therapy
Tofacitinib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tofacitinib. Management: Reduce the adult dose of tofacitinib to 5 mg daily in patients receiving strong CYP3A4 inhibitors. Consider therapy modification
Tolterodine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tolterodine. Management: The maximum recommended adult dose of tolterodine is 2 mg/day when used together with a strong CYP3A4 inhibitor. Consider therapy modification
Tolvaptan: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Tolvaptan. Avoid combination
Toremifene: CYP3A4 Inhibitors (Strong) may enhance the adverse/toxic effect of Toremifene. CYP3A4 Inhibitors (Strong) may increase the serum concentration of Toremifene. Avoid combination
Trabectedin: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Trabectedin. Avoid combination
TraMADol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of TraMADol. Monitor therapy
TraZODone: Nelfinavir may increase the serum concentration of TraZODone. Management: Consider using a lower dose of trazodone when used in combination with nelfinavir. Consider therapy modification
Triazolam: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Triazolam. Avoid combination
Tricyclic Antidepressants: Protease Inhibitors may increase the serum concentration of Tricyclic Antidepressants. Monitor therapy
Udenafil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Udenafil. Avoid combination
Ulipristal: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Ulipristal. Management: This is specific for when ulipristal is being used for signs/symptoms of uterine fibroids (Canadian indication). When ulipristal is used as an emergency contraceptive, patients receiving this combo should be monitored for ulipristal toxicity. Avoid combination
Valbenazine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Valbenazine. Management: Reduce the valbenazine dose to 40 mg daily when combined with strong CYP3A4 inhibitors. Consider therapy modification
Valproate Products: Protease Inhibitors may decrease the serum concentration of Valproate Products.Monitor therapy
Vardenafil: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Vardenafil. Management: Recommendations regarding concomitant use of vardenafil with strong CYP3A4 inhibitors may vary depending on brand name (e.g., Levitra, Staxyn) or by international labeling. See full drug interaction monograph for details. Consider therapy modification
Vemurafenib: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Vemurafenib.Avoid combination
Venetoclax: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Venetoclax. Management: These combinations are contraindicated during venetoclax initiation and ramp-up. In patients receiving steady venetoclax doses after completing ramp-up, reduce the venetoclax by at least 75% if strong CYP3A4 inhibitor use cannot be avoided. Consider therapy modification
Vilanterol: May increase the serum concentration of CYP3A4 Inhibitors (Strong). Monitor therapy
Vilazodone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Vilazodone. Management: Limit maximum adult vilazodone dose to 20 mg daily in patients receiving strong CYP3A4 inhibitors. The original vilazodone dose can be resumed following discontinuation of the strong CYP3A4 inhibitor. Consider therapy modification
VinCRIStine (Liposomal): CYP3A4 Inhibitors (Strong) may increase the serum concentration of VinCRIStine (Liposomal). Avoid combination
Vindesine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Vindesine. Monitor therapy
Vinflunine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Vinflunine. Avoid combination
Vinorelbine: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Vinorelbine. Monitor therapy
Vorapaxar: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Vorapaxar. Avoid combination
Voriconazole: May increase the serum concentration of Nelfinavir. Monitor therapy
Warfarin: Nelfinavir may decrease the serum concentration of Warfarin. Nelfinavir may increase the serum concentration of Warfarin. Monitor therapy
Zidovudine: Protease Inhibitors may decrease the serum concentration of Zidovudine. Monitor therapy
Zolpidem: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Zolpidem. Monitor therapy
Zopiclone: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Zopiclone. Management: The initial starting adult dose of zopiclone should not exceed 3.75 mg if combined with a strong CYP3A4 inhibitor. Monitor patients for signs and symptoms of zopiclone toxicity if these agents are combined. Consider therapy modification
Zuclopenthixol: CYP3A4 Inhibitors (Strong) may increase the serum concentration of Zuclopenthixol. Management: Consider zuclopenthixol dosage reduction with concomitant use of a strong CYP3A4 inhibitor (eg, ketoconazole) in poor CYP2D6 metabolizers or with strong CYP2D6 inhibitors (eg, paroxetine). Monitor for increased zuclopenthixol levels/toxicity. Consider therapy modification
Adverse Reactions
>10%: Gastrointestinal: Diarrhea (adults: 14% to 20%; children: 39% to 47%)
1% to 10%:
Central nervous system: Anxiety (<2%), depression (<2%), dizziness (<2%), drowsiness (<2%), emotional lability (<2%), headache (<2%), insomnia (<2%), malaise (<2%), migraine (<2%), myasthenia (<2%), pain (<2%), paresthesia (<2%), seizure (<2%), sleep disorder (<2%), suicidal ideation (<2%)
Dermatologic: Skin rash (adults: 1% to 3%), dermatitis (<2%), diaphoresis (<2%), folliculitis (<2%), fungal dermatitis (<2%), maculopapular rash (<2%), pruritus (<2%), urticaria (<2%)
Endocrine & metabolic: Dehydration (<2%), hyperglycemia (<2%), hyperlipidemia (<2%), hyperuricemia (<2%), hypoglycemia (<2%), increased amylase (<2%), increased gamma-glutamyl transferase (<2%), increased lactate dehydrogenase (<2%), lipodystrophy (<2%), redistribution of body fat (<2%)
Gastrointestinal: Nausea (adults: 3% to 7%), flatulence (adults: 1% to 5%), abdominal pain (<2%), anorexia (<2%), dyspepsia (<2%), epigastric pain (<2%), gastrointestinal hemorrhage (<2%), oral mucosa ulcer (<2%), pancreatitis (<2%), vomiting (<2%)
Genitourinary: Sexual disorder (<2%), urine abnormality (<2%)
Hematologic & oncologic: Lymphocytopenia (adults: 1% to 6%), decreased neutrophils (adults: 1% to 5%), anemia (<2%), leukopenia (<2%), thrombocytopenia (<2%)
Hepatic: Abnormal hepatic function tests (<2%), hepatitis (<2%), increased serum alkaline phosphatase (<2%), increased serum transaminases (<2%)
Hypersensitivity: Hypersensitivity reaction (<2%; including bronchospasm, edema, and skin rash)
Neuromuscular & skeletal: Arthralgia (<2%), arthritis (<2%), back pain (<2%), hyperkinesia (<2%), increased creatine phosphokinase (<2%), lipoatrophy (<2%), lipotrophy (<2%), muscle cramps (<2%), myalgia (<2%), myopathy (<2%), weakness (<2%)
Ophthalmic: Acute iritis (<2%), eye disease (<2%)
Renal: Nephrolithiasis (<2%)
Respiratory: Dyspnea (<2%), pharyngitis (<2%), rhinitis (<2%), sinusitis (<2%)
Miscellaneous: Fever (<2%)
<1%, postmarketing, and/or case reports: Hyperbilirubinemia, immune reconstitution syndrome, jaundice, metabolic acidosis, prolonged Q-T interval on ECG, torsades de pointes
Warnings/Precautions
Concerns related to adverse effects:
• Diarrhea: Diarrhea occurs frequently with use, particularly in children; a secretory diarrhea mediated via a calcium-dependent process may also occur; calcium carbonate administered at the same time as nelfinavir has been used to treat this adverse effect in adults without affecting plasma concentrations of nelfinavir or its major metabolite.
• Fat redistribution: May cause redistribution of fat (eg, buffalo hump, peripheral wasting with increased abdominal girth, cushingoid appearance).
• Immune reconstitution syndrome: Patients may develop immune reconstitution syndrome resulting in the occurrence of an inflammatory response to an indolent or residual opportunistic infection during initial HIV treatment or activation of autoimmune disorders (eg, Graves disease, polymyositis, Guillain-Barré syndrome) later in therapy; further evaluation and treatment may be required.
Disease-related concerns:
• Diabetes: Changes in glucose tolerance, hyperglycemia, exacerbation of diabetes, DKA, and new-onset diabetes mellitus have been reported in patients receiving protease inhibitors.
• Hemophilia A or B: Use with caution in patients with hemophilia A or B; increased bleeding during protease inhibitor therapy has been reported.
• Hepatic impairment: May cause hepatitis and/or exacerbate preexisting hepatic dysfunction; use with caution in patients with underlying hepatic disease, such as hepatitis B or C or cirrhosis; use not recommended with moderate-to-severe impairment.
Concurrent drug therapy issues:
• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.
Monitoring Parameters
Liver function tests, viral load, CD4 count, triglycerides, cholesterol, blood glucose, CBC with differential
Pregnancy Risk Factor
B
Pregnancy Considerations
Nelfinavir has a minimal to low level of transfer across the human placenta. No increased risk of overall birth defects has been observed following first trimester exposure according to data collected by the antiretroviral pregnancy registry. Maternal antiretroviral therapy (ART) may increase the risk of preterm delivery, although available information is conflicting possibly due to variability of maternal factors (disease severity; gestational age at initiation of therapy); however, maternal antiretroviral medication should not be withheld due to concerns of preterm birth. Information related to stillbirth, low birth weight, and small for gestational age infants is limited. Long-term follow-up is recommended for all infants exposed to antiretroviral medications; children who develop significant organ system abnormalities of unknown etiology (particularly of the CNS or heart) should be evaluated for potential mitochondrial dysfunction. Hyperglycemia, new onset of diabetes mellitus, or diabetic ketoacidosis have been reported with PIs; it is not clear if pregnancy increases this risk.
The Health and Humans Services (HHS) Perinatal HIV Guidelines do not recommended nelfinavir for initial therapy in antiretroviral-naive pregnant females due to lower viral suppression when compared to other regimens. The standard twice daily dose may be used when needed; the three times daily dosing is not recommended during pregnancy.
In general, ART is recommended for all pregnant females with HIV to keep the viral load below the limit of detection and reduce the risk of perinatal transmission. When HIV is diagnosed during pregnancy in a female who has never received antiretroviral therapy, ART should begin as soon as possible after diagnosis. Females who become pregnant on a stable ART regimen may continue that regimen if viral suppression is effective, appropriate drug exposure can be achieved, contraindications for use in pregnancy are not present, and the regimen is well tolerated. Monitoring during pregnancy is more frequent than in nonpregnant adults; ART should be continued postpartum for all females living with HIV.
Health care providers are encouraged to enroll pregnant females exposed to antiretroviral medications as early in pregnancy as possible in the Antiretroviral Pregnancy Registry (1-800-258-4263 or http://www.APRegistry.com). Health care providers caring for HIV-infected females and their infants may contact the National Perinatal HIV Hotline (888-448-8765) for clinical consultation (HHS [perinatal] 2017).
Patient Education
• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)
• Patient may experience nausea, vomiting, flatulence, lack of appetite, or diarrhea. Have patient report immediately to prescriber signs of infection, signs of high blood sugar (confusion, feeling sleepy, more thirst, hunger, passing urine more often, flushing, fast breathing, or breath that smells like fruit), signs of depression (suicidal ideation, anxiety, emotional instability, or illogical thinking), bruising, bleeding, change in body fat, or signs of Stevens-Johnson syndrome/toxic epidermal necrolysis (red, swollen, blistered, or peeling skin [with or without fever]; red or irritated eyes; or sores in mouth, throat, nose, or eyes) (HCAHPS).
• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.
Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for healthcare professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience and judgment in diagnosing, treating and advising patients.
Further information
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
