Interaction between Potassium-Depleting Diuretics and Lovastatin in Hypercholesterolemic Ambulatory Care Patients

Abstract

Objective: To evaluate the potential impact of potassium-depleting diuretics on the efficacy of lovastatin. Design: A retrospective study of ambulatory patients taking lovastatin and thiazide or loop diuretics was conducted. Setting: Ambulatory care patients with coexisting hypercholesterolemia and hypertension from a Veterans Affairs Medical Center. Participants: A total of 32 patients were studied, 13 of whom had been taking lovastatin before diuretics were added. Another 19 patients had been receiving diuretics before lovastatin was initiated. The changes in their total cholesterol from baseline were recorded and analyzed. Main Outcome Measures: In all the patients taking lovastatin and diuretics concurrently, total cholesterol concentrations dropped initially, followed by a rise despite continuation of therapy with lovastatin. The reason for this initial drop in total cholesterol following 1 month of concurrent therapy is the subject of further investigation in a prospective study. Results: Regardless of the order of administration of the lipid-lowering and antihypertensive drugs, serum cholesterol rose 20% from its nadir. Conclusions: Patients taking potassium-depleting diuretics and a hepatic hydroxymethylglutaryl-coenzyme A reductase enzyme inhibitor (lovastatin) concurrently do not seem to benefit substantially from the lipid-lowering effect of lovastatin, probably because of a functional antagonism of the lipid-lowering effect of lovastatin by potassium-depleting diuretics.