Drug Interaction Report

MONITOR: Coadministration with inhibitors of the hepatic uptake transporter OATP 1B1 (e.g., rifampin, cyclosporine, paritaprevir) or the hepatic efflux transporter MRP2 (e.g., ritonavir) may increase the systemic exposure to valsartan, which is a substrate of both transporters.

MANAGEMENT: Caution is advised if valsartan is used in combination with inhibitors of OATP 1B1 or MRP2. Pharmacologic response and blood pressure should be monitored more closely following the addition, discontinuation, or change of dosage of the transporter inhibitor, and the valsartan dosage adjusted as necessary.

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.