Increase in serum-lipids during treatment of hypertension with chlorthalidone.

Fasting concentrations of serum cholesterol and triglyceride were measured before and during therapy in 63 patients with uncomplicated primary (essential) hypertension. The patients were divided into two groups, and diet therapy was applied equally to both groups. One group of 31 patients received no other therapy; the other 32 received chlorthalidone in addition to diet. Diet therapy consisted of no added sodium, caloric restriction if overweight, and consumption of foods low in lipids. On diet therapy alone serum-cholesterol fell by 11 mg/dl (P less than 0-02 vs pretreatment value) and serum-triglyceride was unchanged. When chlorthalidone was prescribed in addition to diet, serum cholesterol rose by 12 mg/dl and triglyceride by 36 mg/dl (P less than 0-005 vs pretreatment value for both). Serum-lipids were similar in the two groups before treatment; during therapy both serum cholesterol (P less than 0-05) and triglyceride (P less than 0-005) concentrations were higher in the chlorthalidone group. Thus, despite the prescription of lipid-lowering and calorie-restricted diets, serum-lipids became slightly raised when chlorthalidone was used as the sole drug in the treatment of hypertension.