The purpose of this study was to evaluate the long-term efficacy and tolerability of pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, in elderly patients with hypercholesterolemia. Pravastatin was administered for 12 months at a mean final dose of 9.9 mg/d to 208 elderly patients (mean [+/- SD] age, 70 +/- 7 years) with levels of total serum cholesterol greater than 5.69 mmol/L. The mean total cholesterol level was significantly decreased from 6.85 +/- 0.80 mmol/L to 5.59 +/- 0.70 mmol/L after 3 months, and this decrease was maintained thereafter. A similar change was observed in the mean serum level of low-density lipoprotein cholesterol. Although the mean serum level of high-density lipoprotein cholesterol in all the patients did not change significantly, the level in 34 patients with a value lower than 1.03 mmol/L was significantly increased after 3 months and thereafter. The serum level of triglycerides in all patients was significantly decreased after 3 months and thereafter and the decrease was more marked in 101 patients with levels greater than 1.73 mmol/L. In 168 elderly patients receiving 10 mg/d of pravastatin, there were significant negative correlations between the percent decrease in total cholesterol and both baseline total serum cholesterol level (r = -.354, P < 0.001) and age (r = -.208, P = 0.007). No serious side effects were observed. These results indicate that long-term administration of pravastatin is beneficial in the treatment of hypercholesterolemia in elderly patients.