Drug Interactions between olaparib and rasagiline

GENERALLY AVOID: Grapefruit juice may significantly increase the plasma concentrations of olaparib. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. In a drug interaction study with 57 patients, mean olaparib systemic exposure (AUC) was increased approximately 2.7-fold by the potent CYP450 3A4 inhibitor itraconazole. Simulations using physiologically-based pharmacokinetic (PBPK) models suggest that a moderate inhibitor (fluconazole) may increase the AUC of olaparib by 2.2-fold. The interaction has not been studied with grapefruit juice. 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. Increased exposure to olaparib may increase the risk of adverse effects such as hematologic toxicity, nausea, vomiting, diarrhea, anorexia, dyspepsia, and abdominal pain or discomfort.

MANAGEMENT: Food containing grapefruit, grapefruit juice, Seville orange (a citrus relative of the grapefruit), or Seville orange juice should be avoided during treatment with olaparib. Some authorities also recommend avoiding starfruit (carambola) and pomegranate.

GENERALLY AVOID: Foods that contain large amounts of tyramine may precipitate a hypertensive crisis in patients treated with monoamine oxidase (MAO) inhibitors. The mechanism involves inhibition of MAO-A, the enzyme responsible for metabolizing exogenous amines such as tyramine in the gut and preventing them from being absorbed intact. Once absorbed, tyramine is metabolized to octopamine, a substance that is believed to displace norepinephrine from storage granules. Although rasagiline is a selective inhibitor of MAO-B at the recommended dosages of 0.5 or 1 mg/day, selectivity is not absolute and may diminish with increasing dosage. There were no cases of hypertensive crisis in the clinical development program associated with rasagiline treatment at 1 mg/day, in which most patients did not follow dietary tyramine restriction. However, rare cases of hypertensive crisis have been reported during the postmarketing period in patients who ingested unknown amounts of tyramine-rich foods while taking recommended dosages of rasagiline or selegiline, another MAO-B inhibitor.

Rasagiline peak plasma concentration (Cmax) and systemic exposure (AUC ) are decreased by approximately 60% and 20%, respectively, during coadministration with a high-fat meal. The time to peak concentration (Tmax) is not affected by food.

MANAGEMENT: Dietary restriction is not ordinarily required during rasagiline treatment with respect to most foods and beverages that may contain tyramine such as air-dried and fermented meats or fish, aged cheeses, most soybean products, yeast extracts, red wine, beer, and sauerkraut. However, certain foods like some of the aged cheeses (e.g., Boursault, Liederkrantz, Mycella, Stilton) may contain very high amounts of tyramine and could potentially cause a hypertensive reaction in patients taking rasagiline even at recommended dosages due to increased sensitivity to tyramine. Patients should be advised to avoid ingesting very high levels of tyramine (e.g., greater than 150 mg), and to promptly seek medical attention if they experience potential signs and symptoms of a hypertensive crisis such as severe headache, visual disturbances, confusion, stupor or coma, seizures, chest pain, unexplained nausea or vomiting, and stroke-like symptoms. Rasagiline should not be used at dosages exceeding 1 mg/day (0.5 mg/day for patients with mild hepatic impairment or concomitant use of ciprofloxacin or other CYP450 1A2 inhibitors), as it can increase the risk of hypertensive crisis and other adverse reactions associated with nonselective inhibition of MAO. Rasagiline can be administered with or without food.