Drug Interactions between Biaxin and emtricitabine / nelfinavir / tenofovir
This report displays the potential drug interactions for the following 2 drugs:
- Biaxin (clarithromycin)
- emtricitabine/nelfinavir/tenofovir
Interactions between your drugs
clarithromycin nelfinavir
Applies to: Biaxin (clarithromycin) and emtricitabine / nelfinavir / tenofovir
MONITOR: Coadministration with nelfinavir may increase the plasma concentrations of drugs that are substrates of the CYP450 3A4 isoenzyme. The mechanism is decreased clearance due to inhibition of CYP450 3A4 activity by nelfinavir.
MANAGEMENT: Caution is advised if nelfinavir must be used concurrently with medications that undergo metabolism by CYP450 3A4, particularly those with a narrow therapeutic range. Dosage adjustments as well as clinical and laboratory monitoring may be appropriate for some drugs whenever nelfinavir is added to or withdrawn from therapy.
References
- (2001) "Product Information. Viracept (nelfinavir)." Agouron Pharma Inc
Drug and food interactions
clarithromycin food
Applies to: Biaxin (clarithromycin)
Grapefruit juice may delay the gastrointestinal absorption of clarithromycin but does not appear to affect the overall extent of absorption or inhibit the metabolism of clarithromycin. The mechanism of interaction is unknown but may be related to competition for intestinal CYP450 3A4 and/or absorptive sites. In an open-label, randomized, crossover study consisting of 12 healthy subjects, coadministration with grapefruit juice increased the time to reach peak plasma concentration (Tmax) of both clarithromycin and 14-hydroxyclarithromycin (the active metabolite) by 80% and 104%, respectively, compared to water. Other pharmacokinetic parameters were not significantly altered. This interaction is unlikely to be of clinical significance.
References
- Cheng KL, Nafziger AN, Peloquin CA, Amsden GW (1998) "Effect of grapefruit juice on clarithromycin pharmacokinetics." Antimicrob Agents Chemother, 42, p. 927-9
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
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
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