The effect of cholestyramine and colestipol on the absorption of hydrochlorothiazide.

The effect of cholestyramine and colestipol on the absorption of a single orally administered dose of 75 mg hydrochlorothiazide was determined. Both urinary excretion and plasma levels of hydrochlorothiazide were measured. Cholestyramine or colestipol administration decreased the total urinary excretion of hydrochlorothiazide by 85 and 43%, respectively. Similar effects were also noted on plasma hydrochlorothiazide levels.