Drug Interactions between BuSpar and telaprevir

GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of buspirone. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

ADJUST DOSING INTERVAL: In a small, randomized, crossover study, the consumption of large amounts of grapefruit juice (compared to water) was associated with significantly increased plasma buspirone concentrations, slightly prolonged elimination half-lives, and delayed times to reach peak drug concentration. The perceived pharmacodynamic effect of buspirone, as measured by subjective drowsiness and overall subjective drug effect, was also enhanced by grapefruit juice. These alterations may stem from the delay of gastric emptying as well as inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall induced by certain compounds present in grapefruits.

MANAGEMENT: Patients receiving buspirone should be advised to avoid consumption of alcohol. Patients also should preferably avoid the consumption of large amounts of grapefruits and grapefruit juice to prevent any undue fluctuations in plasma drug levels. If this is not possible, the buspirone dose should be taken at least 2 hours before or 8 hours after grapefruit or grapefruit juice. Monitoring for increased CNS depression is recommended.

ADJUST DOSING INTERVAL: Food significantly enhances the oral bioavailability of telaprevir. When given with a meal containing 533 kcal and 21 g fat, telaprevir systemic exposure (AUC) increased by 237% compared to administration under fasting conditions. The type of meal also affects the exposure to telaprevir. Relative to fasting, telaprevir AUC increased by approximately 117% with a low-fat meal (249 kcal; 3.6 g fat) and 330% with a high-fat meal (928 kcal; 56 g fat). In Phase 3 clinical trials, telaprevir doses were administered within 30 minutes of completing a meal or snack containing approximately 20 grams of fat.

MANAGEMENT: Telaprevir should be administered with food containing approximately 20 grams of fat. Patients should be advised that the fat content of the meal or snack is critical to the absorption of telaprevir. Food taken with telaprevir should be ingested within 30 minutes prior to each dose. Examples of some foods that could be taken with telaprevir include: bagel with cream cheese; half cup of nuts; 3 tablespoons of peanut butter; 1 cup of ice cream; 2 ounces of American or cheddar cheese; 2 ounces of potato chips; or half cup of trail mix.