Antihypertensive and Metabolic Effects of Single and Combined Atenolol Regimens

The antihypertensive and metabolic effects of placebo (PL), a fixed combination of hydrochlorothiazide (25 mg) and triamterene (50 mg) (HCTZ/TRI), atenolol (25 mg) (Ate-25), atenolol (50 mg) (Ate-50) and their combination with HCTZ/TRI given once daily, were tested on 256 patients with mild-to-moderate essential hypertension. After 3 weeks of PL monotherapy, 43 patients were randomized to PL (group 1), 41 patients to HCTZ/TRI (group 2), 44 patients to Ate-25 (group 3), 42 patients to Ate-50 (group 4), 43 patients to Ate-25/HCTZ/TRI (group 5), and 43 patients to Ate-50/HCTZ/TRI (group 6) in a double-blind parallel design study and were followed for 4 weeks. At the end of week 7, those patients who were randomized to groups 5 and 6 were allowed to continue for an additional 12 weeks, if their arterial pressure was satisfactorily controlled. Complete blood counts, blood chemistries, urinalyses, and electrocardiograms were done initially and during the study. Monotherapy with HCTZ/TRI, Ate-25, and Ate-50 had significant and equal antihypertensive effects compared with placebo. (P <.01). However, the combination of Ate-25/HCTZ/TRI and Ate-50/HCTZ/TRI resulted in further reduction of arterial pressure with the effect being greatest with Ate-50/HCTZ/TRI (P <.001). Patient groups 3 through 6 had also slower heart rates compared with groups 1 and 2 (P <.01). Mild, but statistically significant, increases in BUN, glucose, triglycerides, and uric acid were noted in groups 2, 5, and 6 (P <.05). These results suggest: 1) Ate-25 was equipotent to Ate-50, 2) their antihypertensive effectiveness was further enhanced with the addition of HCTZ/TRI, and 3) the greatest effect was noted with the combination of Ate-50/HCTZ/TRI.