Drug Interactions between guanfacine and vericiguat

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of guanfacine. The risk of adverse reactions such as hypotension, bradycardia, and sedation may increase. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. Ketoconazole, a potent CYP450 3A4 inhibitor, has been reported to increase guanfacine peak plasma concentration (Cmax) and systemic exposure (AUC) by approximately 2- and 3-fold, respectively. A computer simulation suggests that fluconazole, a moderate CYP450 3A4 inhibitor, would increase guanfacine Cmax and AUC by about 1.5- and 2-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.

GENERALLY AVOID: Alcohol may enhance the sedative and hypotensive effects of guanfacine.

GENERALLY AVOID: Administration of extended-release guanfacine with a high-fat meal may increase the bioavailability of guanfacine. When a single 4 mg dose of extended-release guanfacine was administered to adult volunteers with a high-fat breakfast, mean guanfacine peak plasma concentration (Cmax) and systemic exposure (AUC) increased by approximately 75% and 40%, respectively, compared to dosing in a fasted state.

MANAGEMENT: Patients treated with guanfacine should avoid consumption of grapefruit and grapefruit juice. In addition, it is preferable to avoid or limit the use of alcohol during treatment. Patients should be advised against driving or operating hazardous machinery until they know how the medication affects them. The extended-release formulation of guanfacine should not be taken together with a high-fat meal.

ADJUST DOSING INTERVAL: Administration of vericiguat with food reduces its pharmacokinetic variability and increases its exposure. Vericiguat is less soluble at neutral pH than at acidic pH. Administration of vericiguat with a high-fat, high-calorie meal or low-fat, high-carbohydrate meal increased time to reach peak plasma concentration (Tmax) from about 1 hour (fasted) to about 4 hours (fed) and increased vericiguat systemic exposure (AUC) by 19% and peak plasma concentration (Cmax) by 9% for the 5 mg tablet and by 44% (AUC) and 41% (Cmax) for the 10 mg tablet as compared with the fasted state. Concurrent treatment with drugs that increase gastric pH, such as proton pump inhibitors or antacids, decrease vericiguat AUC by about 30%. Co-treatment with drugs that increase gastric pH did not affect vericiguat exposure in patients with heart failure when vericiguat was taken as directed with food.

MANAGEMENT: Administer vericiguat with food to ensure maximal exposure and decrease pharmacokinetic variability.