Drug Interactions between bromocriptine and ivosidenib

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of ivosidenib. 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. Pharmacokinetic data are available for the potent CYP450 3A4 inhibitor, itraconazole, and the moderate inhibitor, fluconazole. When a single 250 mg dose of ivosidenib was administered with itraconazole 200 mg once daily for 18 days, ivosidenib systemic exposure (AUC) increased to 269% of control, with no change in peak plasma concentration (Cmax). Based on physiologically-based pharmacokinetic modeling, coadministration of a 500 mg dose of ivosidenib with fluconazole (dosed to steady-state) is predicted to increase ivosidenib single-dose AUC to 173% of control, while multiple-dosing of both is predicted to increase ivosidenib steady-state Cmax and AUC to 152% and 190% of control, 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. Increased exposure to ivosidenib may increase the risk of QT interval prolongation, which has been associated with ventricular arrhythmias including torsade de pointes and sudden death.

GENERALLY AVOID: Coadministration with a high-fat meal may increase the plasma concentrations of ivosidenib. According to the product labeling, administration of a single dose with a high-fat meal (approximately 900 to 1000 calories; 500 to 600 calories in fat, 250 calories in carbohydrate, 150 calories in protein) increased ivosidenib Cmax and AUC by 98% and 25%, respectively, in healthy study subjects.

MANAGEMENT: Ivosidenib may be administered with or without food, but should not be administered with a high-fat meal. Patients should avoid consumption of grapefruit and grapefruit juice during treatment with ivosidenib.

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

MANAGEMENT: Patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

MONITOR: Nicotine may cause vasoconstriction in some patients and potentiate the ischemic response to ergot alkaloids.

MANAGEMENT: Caution may be advisable when ergot alkaloids are used in combination with nicotine products. Patients should be advised to seek immediate medical attention if they experience potential symptoms of ischemia such as coldness, pallor, cyanosis, numbness, tingling, or pain in the extremities; muscle weakness; severe or worsening headache; visual disturbances; severe abdominal pain; chest pain; and shortness of breath.