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Drug Interactions between amiodarone and eletriptan

This report displays the potential drug interactions for the following 2 drugs:

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Interactions between your drugs

Moderate

amiodarone eletriptan

Applies to: amiodarone and eletriptan

MONITOR: Coadministration with inhibitors of CYP450 3A4 may significantly increase the plasma concentrations of eletriptan, which is primarily metabolized by the isoenzyme. According to the product labeling, eletriptan peak plasma concentration (Cmax) and systemic exposure (AUC) increased by nearly 3-fold and 6-fold, respectively, during coadministration with the potent inhibitor ketoconazole (400 mg). Likewise, erythromycin (1000 mg) increased eletriptan Cmax by 2-fold and AUC by nearly 4-fold. The half-life of eletriptan increased from about 5 hours to 8 hours with ketoconazole and 7 hours with erythromycin. Verapamil (480 mg), a moderate CYP450 3A4 inhibitor, increased eletriptan Cmax by 2.2-fold and AUC by 2.7-fold, while fluconazole (100 mg), a relatively weak inhibitor, increased eletriptan Cmax by 1.4-fold and AUC by 2-fold. Clinically, this interaction may result in increased risk of vasospastic reactions associated with the use of 5-HT1 receptor agonists, such as coronary artery vasospasm, peripheral vascular ischemia, and colonic ischemia.

MANAGEMENT: Eletriptan should not be used within at least 72 hours of treatment with potent CYP450 3A4 inhibitors such as itraconazole, ketoconazole, nefazodone, delavirdine, most protease inhibitors, and ketolide and certain macrolide antibiotics. The manufacturer makes no specific recommendations for use with less potent inhibitors, but caution is appropriate. Patients should have vital signs monitored regularly and advised to notify their physician if they experience signs and symptoms of vasospasm such as numbness, tingling, or cyanosis in the extremities; muscle pains; weakness; or chest pain or tightness. Alternatively, other 5-HT1 receptor agonists that are not metabolized by CYP450 3A4 may be considered, such as frovatriptan, naratriptan, rizatriptan, sumatriptan, and zolmitriptan.

References (1)
  1. (2003) "Product Information. Relpax (eletriptan)." Pfizer U.S. Pharmaceuticals

Drug and food interactions

Major

amiodarone food

Applies to: amiodarone

GENERALLY AVOID: Grapefruit juice may significantly increase the plasma concentrations of orally administered amiodarone. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruits. In 11 nonsmoking, healthy volunteers, grapefruit juice (300 mL with drug administration, then 3 hours and 9 hours later) increased the mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of amiodarone (17 mg/kg single dose) by 84% and 50%, respectively, compared to water. Formation of the pharmacologically active metabolite, N-desethylamiodarone (N-DEA), was completely inhibited. Clinically, this interaction can lead to altered efficacy of amiodarone, since antiarrhythmic properties of amiodarone and N-DEA appear to differ. In the study, mean increases in PR and QTc intervals of 17.9% and 11.3%, respectively, were observed 6 hours postdose with water, while increases of 10.2% and 3.3%, respectively, were observed after administration with grapefruit juice.

ADJUST DOSING INTERVAL: Food increases the rate and extent of absorption of amiodarone. The mechanism appears to involve the effect of food-induced physiologic changes on drug release from its formulation. In 30 healthy volunteers, administration of a single 600 mg dose of amiodarone following a high-fat meal resulted in a Cmax and AUC that were 3.8 and 2.4 times the respective values under fasting conditions. The time to reach peak plasma concentration (Tmax) was decreased by 37%, indicating an increased rate of absorption. Mean Cmax and AUC for the active metabolite, N-DEA, also increased by 32% and 55%, respectively, but there was no change in the Tmax.

MANAGEMENT: Patients treated with oral amiodarone should avoid consumption of grapefruits and grapefruit juice. In addition, oral amiodarone should be administered consistently with regard to meals.

References (3)
  1. (2002) "Product Information. Cordarone (amiodarone)." Wyeth-Ayerst Laboratories
  2. Libersa CC, Brique SA, Motte KB, et al. (2000) "Dramatic inhibition of amiodarone metabolism induced by grapefruit juice." Br J Clin Pharmacol, 49, p. 373-8
  3. Meng X, Mojaverian P, Doedee M, Lin E, Weinryb I, Chiang ST, Kowey PR (2001) "Bioavailability of Amiodarone tablets administered with and without food in healthy subjects." Am J Cardiol, 87, p. 432-5

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.


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Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor 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.
Unknown No interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.