Drug Interactions between saquinavir and ubrogepant

ADJUST DOSING INTERVAL: Food significantly increases the absorption of saquinavir.

MONITOR: Coadministration with grapefruit juice may increase the plasma concentrations of saquinavir. The primary mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruits. In eight healthy volunteers, ingestion of 400 mL of grapefruit juice prior to administration of a 600 mg dose of saquinavir mesylate increased the area under the plasma concentration-time curve and oral bioavailability of saquinavir by 50% and 100%, respectively, compared to water; however, the increase is not considered clinically relevant. A high degree of intersubject variability in the grapefruit juice effect was also observed. The extent to which this interaction may occur with the saquinavir free base soft gelatin capsule is unknown. However, the saquinavir soft gelatin capsule formulation is no longer commercially available.

MANAGEMENT: Saquinavir mesylate should be taken with meals or within 2 hours after eating to enhance bioavailability. Patients should be advised to avoid the consumption of large amounts of grapefruit and grapefruit juice during saquinavir therapy unless otherwise directed by their doctor, as the interaction is unreliable and subject to a high degree of interpatient variation.

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.