Metabolic effects of a change in antihypertensive treatment.

Twenty hypertensive men, aged 58 to 62 years, who had been treated with a combination of different drugs for many years, had their therapy changed in a stepwise manner to a combination of 50 mg of atenolol per day and 2 to 15 mg of prazosin per day. The effects of each change of treatment were assessed separately five to six months after the change. Serum lipids and high-density lipoprotein concentrations were determined, and an intravenous glucose tolerance test was performed at the start of the study and after each change. In the group in which therapy was changed from a diuretic to prazosin, serum cholesterol and triglyceride concentrations decreased significantly by 11 and 42 percent, respectively, but in the group in which therapy was changed from hydralazine to prazosin, there were no alterations in serum lipids or lipoproteins. The changes in therapy had no overall effects on glucose or insulin parameters evaluated with an intravenous glucose tolerance test. However, prazosin was associated with an increase in the fasting blood glucose level and a decrease in the peak insulin value after glucose injection, both of which were dose-related effects. The data indicate that the glucose turnover was at least as good after a switch from diuretic to prazosin treatment as before at lower insulin values. In those patients in whom therapy was switched from propranolol to 50 mg of atenolol per day, the serum triglyceride concentration decreased by about 10 percent, whereas in the group in which therapy was changed from 100 to 50 mg of atenolol per day, there were no serum lipid or lipoprotein alterations. The results show that a combination of 50 mg of atenolol per day and prazosin has metabolic advantages over combined diuretic and propranolol treatment. Such advantages may be of importance in the long-term treatment of hypertensive patients.