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Drug Interactions between amprenavir and ospemifene

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

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Interactions between your drugs

Moderate

amprenavir ospemifene

Applies to: amprenavir and ospemifene

MONITOR: Coadministration with potent inhibitors of CYP450 3A4 may increase the plasma concentrations of ospemifene, which is partially metabolized by the isoenzyme. In 12 postmenopausal women given the potent CYP450 3A4 inhibitor ketoconazole 400 mg once daily for 8 days, administration of ospemifene 60 mg after breakfast on day 5 of ketoconazole treatment resulted in 1.5- and 1.4-fold increases in ospemifene peak plasma concentration (Cmax) and systemic exposure (AUC), respectively, compared to administration of ospemifene alone. The potential for increased risk of adverse events such as hot flush, thromboembolism, and endometrial or breast cancer should be considered.

MANAGEMENT: Caution is advised when ospemifene is used with potent CYP450 3A4 inhibitors. Patients should be advised to seek medical attention if they develop potential signs and symptoms of thromboembolism such as chest pain, shortness of breath, and pain or swelling in the arms or legs.

References (1)
  1. (2013) "Product Information. Osphena (ospemifene)." Shionogi USA Inc

Drug and food interactions

Moderate

amprenavir food

Applies to: amprenavir

GENERALLY AVOID: Administration with a high-fat meal may decrease the oral bioavailability of amprenavir. The mechanism is unknown. In healthy volunteers, consumption of a standardized high-fat meal decreased the peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of amprenavir (1200 mg single oral dose) by 36% and 21%, respectively, compared to administration in the fasted state. The time to reach Cmax (Tmax) was increased 44% following a high-fat meal.

Grapefruit juice does not appear to significantly affect the pharmacokinetics of amprenavir. In 12 healthy volunteers, administration with grapefruit juice (200 mL) decreased the mean peak plasma concentration (Cmax) of amprenavir (1200 mg single oral dose) by 22% compared to water. The median time to reach Cmax (Tmax) was prolonged from 0.75 to 1.13 hours. These pharmacokinetic changes are not thought to be clinically significant, since antiretroviral response is more closely associated with systemic exposure (AUC) and trough plasma concentration (Cmin), which were not affected in the study.

MANAGEMENT: Amprenavir may be taken with or without food, but should not be taken with a high-fat meal.

References (2)
  1. (2001) "Product Information. Agenerase (amprenavir)." Glaxo Wellcome
  2. Demarles D, Gillotin C, Bonaventure-Paci S, Vincent I, Fosse S, Taburet AM (2002) "Single-dose pharmacokinetics of amprenavir coadministered with grapefruit juice." Antimicrob Agents Chemother, 46, p. 1589-1590
Moderate

ospemifene food

Applies to: ospemifene

ADJUST DOSING INTERVAL: Food significantly enhances the oral bioavailability of ospemifene. In a cross-study comparison, administration of a single 60 mg dose of ospemifene with a high-fat/high-calorie meal (860 kcal) in postmenopausal women increased ospemifene peak plasma concentration (Cmax) and systemic exposure (AUC) by 2.3- and 1.7-fold, respectively, compared to administration under fasted condition. Elimination half-life and time to maximum concentration (Tmax) were not altered. In two separate food effect studies where different ospemifene tablet formulations were given to healthy male volunteers, ospemifene Cmax and AUC increased by 2.3- and 1.8-fold, respectively, with a low-fat/low-calorie meal (300 kcal) and 3.6- and 2.7-fold, respectively, with a high-fat/high-calorie meal (860 kcal) relative to fasting.

MANAGEMENT: Ospemifene should be taken once daily with food.

References (1)
  1. (2013) "Product Information. Osphena (ospemifene)." Shionogi USA Inc

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.

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