Drug Interactions between Mifeprex and ubrogepant

ADJUST DOSING INTERVAL: Food may significantly increase the plasma concentrations of mifepristone.

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of mifepristone. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. Because pharmacokinetic interactions involving grapefruit juice are often subject to a high degree of interpatient variability, the extent to which a given patient may be affected is difficult to predict.

MANAGEMENT: When mifepristone is used daily to control hyperglycemia secondary to hypercortisolism in patients with endogenous Cushing's syndrome, it should be taken with food to achieve consistent plasma drug levels. Patients should be advised to avoid consuming grapefruit or grapefruit juice during treatment with mifepristone, as it may cause increased adverse effects such as headache, dizziness, fatigue, nausea, vomiting, cramping, diarrhea, hypokalemia, adrenal insufficiency, vaginal bleeding, arthralgia, peripheral edema, and hypertension. Because mifepristone is eliminated slowly from the body, the interaction with grapefruit juice may be observed for a prolonged period.

ADJUST DOSE: Grapefruit and grapefruit juice may increase the plasma concentrations of ubrogepant. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. Inhibition of hepatic CYP450 3A4 may also contribute. The interaction has not been studied with grapefruit but has been reported for other CYP450 3A4 inhibitors. When ubrogepant was administered with the potent CYP450 3A4 inhibitor ketoconazole during in vivo studies, ubrogepant peak plasma concentration (Cmax) and systemic exposure (AUC) increased by 5.3- and 9.7-fold, respectively. When administered with the moderate CYP450 3A4 inhibitor verapamil, ubrogepant Cmax and AUC increased by 2.8- and 3.5-fold, respectively. 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.

When administered with a high-fat meal, ubrogepant time to maximum plasma concentration (Tmax) was delayed by 2 hours, which resulted in a 22% decrease in Cmax and no change in AUC. Ubrogepant was administered without regard to food in clinical efficacy studies.

MANAGEMENT: Ubrogepant may be administered with or without food. When coadministered with grapefruit or grapefruit juice, the manufacturer recommends an initial ubrogepant dose of 50 mg. A second dose, if needed, should not be administered within 24 hours of the initial dose.