Isradipine in the treatment of hypertension. Some additional effects observed during a one-year study

After a placebo run-in phase of four weeks' duration, 1.25 mg or 2.5 mg isradipine twice daily orally was administered for one year to 23 patients who had been diagnosed as hypertensive. Good control of blood pressure was recorded in the majority of patients until the third month of treatment. After five months, it was necessary to add a beta-blocker to the treatment regimens of some of the patients in order to maintain the target blood pressure of 140/90 mm Hg. Patients were exercise-tested using bicycle ergometry. After three months, diastolic blood pressure was significantly lower during exercise when comparing the treatment values with those taken at the end of the placebo run-in (baseline values). Values for systolic blood pressure did not differ between treatment and baseline. These results may be explained by the decrease in peripheral vascular resistance produced by isradipine. After one year, the results were modified by the administration of the beta-blocker bopindolol (Sandonorm, Sandoz Pharma Ltd., Basle, Switzerland). Total cholesterol, high-density lipoprotein cholesterol, and apolipoprotein B levels did not change during treatment. Triglycerides were lower after three months, but slightly higher after one year, with an average value lying within the normal range. The influence of isradipine on plasma renin activity (PRA) and aldosterone levels was followed by measuring values at rest and during exercise. It was found that PRA was higher during the first three months, then inversely inhibited to lower levels. Aldosterone levels were also increased after three months, but without a subsequent decrease. The results are compared with those obtained with diltiazem in a similar treatment regimen.