Lipid profiles were determined in 56 elderly patients with benign essential hypertension during an open-label 1-year study of the safety and efficacy of isradipine, a new calcium antagonist, in controlling blood pressure. Patients with diastolic blood pressures between 96 and 115 mm Hg were titrated with isradipine (mean dose of 11 mg/day) to reduce blood pressure to less than 90 mm Hg. Ten of these patients received concomitant hydrochlorothiazide (HCTZ) 50 mg/day for additional control. Sera were analyzed using standard methods at the end of a 2- to 4-week washout period, and at the end of Months 6 and 12, for total cholesterol (CHOL) and HDL- and LDL-cholesterol. Changes in lipid values (mg/dl) from baseline to 12 months with isradipine alone (n = 38) were as follows: CHOL, -7.5; HDL, +3.9 (p less than 0.05); LDL, -6.2; CHOL/HDL, -0.6 (p less than 0.05). For patients receiving concomitant HCTZ (n = 9), the changes were as follows: CHOL, -4.9; HDL, +3.4; LDL, -16.8; CHOL/HDL, -0.4. In conclusion, isradipine alone was associated with significant improvements in HDL cholesterol and total CHOL/HDL ratio. Lipid profiles of patients receiving isradipine and HCTZ were minimally affected. Favorable lipid changes with isradipine suggest that it may have advantages in the treatment of hypertensive patients.