Drug Interaction Report

MONITOR: Maraviroc may potentiate the hypotensive effect of some medications. In clinical trials, symptomatic postural hypotension was observed more often with maraviroc than with placebo when administered to healthy volunteers at higher than recommended dosages. However, when given at the recommended dosage to HIV subjects, postural hypotension occurred at a rate similar to placebo (approximately 0.5%).

MANAGEMENT: Caution is advised when maraviroc is prescribed to patients on concomitant medications known to lower blood pressure. Close monitoring for development of hypotension is recommended. Ambulatory patients should be advised to avoid rising abruptly from a sitting or recumbent position and to notify their doctor if they experience dizziness, lightheadedness, syncope, orthostasis, or tachycardia.

GENERALLY AVOID: Moderate-to-high dietary intake of potassium, especially salt substitutes, may increase the risk of hyperkalemia in some patients who are using angiotensin II receptor blockers (ARBs). ARBs can promote hyperkalemia through inhibition of angiotensin II-induced aldosterone secretion. Patients with diabetes, heart failure, dehydration, or renal insufficiency have a greater risk of developing hyperkalemia.

MANAGEMENT: Patients should receive dietary counseling and be advised to not use potassium-containing salt substitutes or over-the-counter potassium supplements without consulting their physician. If salt substitutes are used concurrently, regular monitoring of serum potassium levels is recommended. Patients should also be advised to seek medical attention if they experience symptoms of hyperkalemia such as weakness, irregular heartbeat, confusion, tingling of the extremities, or feelings of heaviness in the legs.

Administration with food may reduce the bioavailability of maraviroc. According to the product labeling, coadministration of a 300 mg dose of maraviroc with a high-fat breakfast reduced maraviroc peak plasma concentration (Cmax) and systemic exposure (AUC) by 33% in healthy volunteers. However, no food restrictions were used in the clinical studies that demonstrated the safety and efficacy of maraviroc. Therefore, maraviroc can be taken with or without food at the recommended dosage.