Drug Interactions between emtricitabine / nelfinavir / tenofovir and Xtandi
This report displays the potential drug interactions for the following 2 drugs:
- emtricitabine/nelfinavir/tenofovir
- Xtandi (enzalutamide)
Interactions between your drugs
nelfinavir enzalutamide
Applies to: emtricitabine / nelfinavir / tenofovir and Xtandi (enzalutamide)
MONITOR: Coadministration with drugs that are inducers of CYP450 3A4 may decrease the plasma concentrations of protease inhibitors (PIs), which are primarily metabolized by the isoenzyme.
MANAGEMENT: Given the risk of reduced viral susceptibility and resistance development associated with subtherapeutic antiretroviral drug levels, protease inhibitors should be used cautiously with agents that induce CYP450 3A4, particularly if only one PI is used in the antiretroviral regimen. Coadministration of atazanavir without ritonavir and carbamazepine, phenobarbital, or phenytoin is not recommended. Antiretroviral response should be monitored more closely whenever a CYP450 3A4 inducer is added to or withdrawn from therapy, and the antiretroviral regimen adjusted as necessary.
References
- (2001) "Product Information. Invirase (saquinavir)." Roche Laboratories
- (2001) "Product Information. Crixivan (indinavir)." Merck & Co., Inc
- (2001) "Product Information. Viracept (nelfinavir)." Agouron Pharma Inc
- Brooks J, Daily J, Schwamm L (1997) "Protease inhibitors and anticonvulsants." AIDS Clin Care, 9, 87,90
- Barry M, Gibbons S, Back D, Mulcahy F (1997) "Protease inhibitors in patients with HIV disease. Clinically important pharmacokinetic considerations." Clin Pharmacokinet, 32, p. 194-209
- (2001) "Product Information. Agenerase (amprenavir)." Glaxo Wellcome
- Acosta EP, Henry K, Baken L, Page LM, Fletcher CV (1999) "Indinavir concentrations and antiviral effect." Pharmacotherapy, 19, p. 708-12
- Sommadossi JP (1999) "HIV protease inhibitors: pharmacologic and metabolic distinctions." AIDS, 13, s29-40
- Hugen PWH, Burger DM, Brinkman K, terHofstede HJM, Schuurman R, Koopmans PP, Hekster YA (2000) "Carbamazepine-indinavir interaction causes antiretroviral therapy failure." Ann Pharmacother, 34, p. 465-70
- Durant J, Clevenbergh P, Garraffo R, Halfon P, Icard S, DelGiudice P, Montagne N, Schapiro JM, Dellamonica P (2000) "Importance of protease inhibitor plasma levels in HIV-infected patients treated with genotypic-guided therapy: pharmacological data from the Viradapt Study." Aids, 14, p. 1333-9
- (2001) "Product Information. Fortovase (saquinavir)." Roche Laboratories
- (2003) "Product Information. Reyataz (atazanavir)." Bristol-Myers Squibb
- (2003) "Product Information. Lexiva (fosamprenavir)." GlaxoSmithKline
- Liedtke MD, Lockhart SM, Rathbun RC (2004) "Anticonvulsant and antiretroviral interactions." Ann Pharmacother, 38, p. 482-9
- (2005) "Product Information. Aptivus (tipranavir)." Boehringer-Ingelheim
- (2006) "Product Information. Prezista (darunavir)." Ortho Biotech Inc
- Canadian Pharmacists Association (2006) e-CPS. http://www.pharmacists.ca/function/Subscriptions/ecps.cfm?link=eCPS_quikLink
tenofovir enzalutamide
Applies to: emtricitabine / nelfinavir / tenofovir and Xtandi (enzalutamide)
MONITOR: Coadministration with enzalutamide may decrease the plasma concentrations of drugs that are substrates of CYP450 3A4, 2C9, 2C19, and/or P-glycoprotein (P-gp) efflux transporter. The proposed mechanism involves accelerated clearance via these routes due to enzalutamide-mediated induction. The resulting plasma concentrations will depend on the sensitivity of the affected drugs to these isoenzymes.
MANAGEMENT: Caution is advised when enzalutamide is used concomitantly with drugs that are substrates of CYP450 3A4, 2C9, 2C19, and/or P-gp, particularly those with a narrow therapeutic range. Dosage adjustments as well as clinical and laboratory monitoring may be appropriate for some drugs whenever enzalutamide is added to or withdrawn from therapy.
References
- Cerner Multum, Inc. "UK Summary of Product Characteristics."
- Cerner Multum, Inc. "Australian Product Information."
- (2012) "Product Information. Xtandi (enzalutamide)." Astellas Pharma US, Inc
- Benoist G, van Oort I, et al. (2017) "Drug-drug interaction potential in men treated with enzalutamide: Mind the gap." Br J Clin Pharmacol, epub
Drug and food interactions
tenofovir food
Applies to: emtricitabine / nelfinavir / tenofovir
Food enhances the oral absorption and bioavailability of tenofovir, the active entity of tenofovir disoproxil fumarate. According to the product labeling, administration of the drug following a high-fat meal increased the mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of tenofovir by approximately 14% and 40%, respectively, compared to administration in the fasting state. However, administration with a light meal did not significantly affect the pharmacokinetics of tenofovir compared to administration in the fasting state. Food delays the time to reach tenofovir Cmax by approximately 1 hour. Tenofovir disoproxil fumarate may be administered without regard to meals.
References
- (2001) "Product Information. Viread (tenofovir)." Gilead Sciences
Therapeutic duplication warnings
No warnings were found for your selected drugs.
Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.
See also
Drug Interaction Classification
Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit. | |
Moderately clinically significant. Usually avoid combinations; use it only under special circumstances. | |
Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan. | |
No interaction information available. |
Further information
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