Drug Interactions between Addyi and posaconazole

CONTRAINDICATED: Grapefruit juice may increase the plasma concentrations of flibanserin. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. In 26 healthy female subjects, administration of a single 100 mg dose of flibanserin with 240 mL grapefruit juice increased flibanserin peak plasma concentration (Cmax) and systemic exposure (AUC) by 1.1- and 1.4-fold, respectively, compared to administration of flibanserin alone. In general, the effect of grapefruit juice is concentration-, dose- and preparation-dependent, and can vary widely among brands. Certain preparations of grapefruit juice (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition.

ADJUST DOSING INTERVAL: Coadministration of flibanserin with alcohol may potentiate the risk of severe hypotension, syncope, and central nervous system depression. In a dedicated alcohol interaction study, hypotension or syncope requiring therapeutic intervention (ammonia salts and/or placement in supine or Trendelenberg position) occurred in 4 (17%) of 23 subjects given flibanserin 100 mg with 0.4 g/kg alcohol (equivalent to two 12 ounce cans of beer containing 5% alcohol content, two 5 ounce glasses of wine containing 12% alcohol content, or two 1.5 ounce shots of 80-proof spirit in a 70 kg person) consumed over 10 minutes in the morning. In these four subjects, systolic blood pressure reductions ranged from 28 to 54 mmHg and diastolic blood pressure reductions ranged from 24 to 46 mmHg. In addition, 6 (25%) of 24 subjects coadministered flibanserin with 0.8 g/kg alcohol experienced orthostatic hypotension when standing from a sitting position. Systolic and diastolic blood pressure reductions in these 6 subjects ranged from 22 to 48 mmHg and 0 to 27 mmHg, respectively, with one requiring therapeutic intervention. No adverse events requiring therapeutic intervention were observed when flibanserin or alcohol was administered alone. Somnolence was reported in 67%, 74%, and 92% of subjects who received flibanserin alone, flibanserin with 0.4 g/kg ethanol, and flibanserin with 0.8 g/kg ethanol, respectively. Subsequent data from postmarketing trials showed that the risk of severe hypotension and syncope was reduced when women who consumed up to two alcoholic drinks waited at least two hours before taking flibanserin.

MANAGEMENT: Concomitant use of flibanserin with moderate or potent CYP450 3A4 inhibitors such as grapefruit juice is considered contraindicated. The patient should be advised to avoid the consumption of grapefruit and grapefruit juice during treatment, and to take flibanserin at bedtime to minimize the risk of hypotension, syncope, accidental injury, and central nervous system depression. In addition, patients should consume no more than 1 to 2 alcoholic drinks and discontinue drinking alcohol at least two hours before taking flibanserin at bedtime; otherwise, they should skip the flibanserin dose that evening. Alcohol should not be consumed until at least the morning after taking flibanserin at bedtime. A standard alcoholic drink contains 14 g of pure alcohol and is equivalent to one 12-ounce regular beer (5% alcohol), 5-ounces wine (12% alcohol), or 1.5 ounces of distilled spirits/shot (40% alcohol).

ADJUST DOSING INTERVAL: Food significantly increases the absorption of posaconazole from the oral suspension but only modestly from the delayed-release tablet. Following single-dose administration, posaconazole mean peak plasma concentration (Cmax) and systemic exposure (AUC) are approximately 2.5 to 3 times higher when the oral suspension is given with a nonfat meal or a nutritional supplement (14 grams of fat) than when given under fasting conditions, and approximately 3.5 to 4 times higher when given during or 20 minutes after a high-fat meal (50 grams of fat) than under fasting conditions. Acidic beverages may also increase posaconazole absorption. In 12 healthy volunteers, administration of a single 400 mg dose of posaconazole suspension with 12 ounces of ginger ale increased posaconazole Cmax by 92% and AUC by 70% compared to administration after fasting. In contrast, the Cmax and AUC of posaconazole increased by just 16% and 51%, respectively, when posaconazole tablets were given as a single 300 mg dose to healthy volunteers after a high-fat meal relative to a fasted state.

GENERALLY AVOID Concomitant use of alcohol and posaconazole administered in the form of delayed-release oral suspension may lead to a faster release of posaconazole. An in vitro dissolution study determined a potential for alcohol-induced dose-dumping with the delayed-release oral suspension of posaconazole.

MONITOR: In 5 study subjects, posaconazole Cmax decreased by 27% to 53% and AUC decreased by 33% to 51% when the oral suspension was administered via a nasogastric tube as opposed to orally.

MANAGEMENT: Posaconazole tablets should be taken with food, whereas posaconazole oral suspension should be administered during or immediately (i.e., within 20 minutes) following a full meal to enhance bioavailability. Patients who cannot eat a full meal should take the suspension with a liquid nutritional supplement or an acidic carbonated beverage such as ginger ale. In patients who cannot eat a full meal or tolerate an oral nutritional supplement or an acidic carbonated beverage and who do not have the option of taking another formulation of posaconazole, alternative antifungal therapy should be considered; otherwise, monitor patients closely for breakthrough fungal infections. Patients receiving posaconazole via a nasogastric tube should also be closely monitored due to increased risk of treatment failure associated with lower plasma exposure. Administration of alcohol with posaconazole from the delayed-release oral suspension formulation is not recommended.