A long-term study of atenolol and doxazosin in mild and moderate hypertension.

The efficacy and tolerability of doxazosin and atenolol in the management of mild and moderate hypertension were compared in a multicentre, parallel study, the first year of which was randomized and double-blind. Patients who completed this first year were invited to enter a two-year extension phase; the results after the first year are presented. A total of 228 patients entered the double-blind phase (118 received atenolol). A reduction in dose was required by 4% in each group; eight patients on doxazosin and 11 on atenolol were withdrawn due to adverse effects. Ninety-three of the 100 doxazosin patients and 88 of the 104 atenolol patients who completed the double-blind phase agreed to participate in the open extension study. At 24 months, the mean dose of doxazosin was 5.2 mg/day, and of atenolol 66.7 mg/day. From baseline levels of BP of 158/104 mmHg in the doxazosin group and 161/103 mmHg in the atenolol group, average reductions at 24 months were -16/-14 and -19/-15 mmHg respectively. Neither drug had a significant effect on total cholesterol levels. At all four points of measurement over the two years, doxazosin decreased blood triglyceride levels and increased high density lipoprotein (HDL) cholesterol and the HDL: total cholesterol ratio. Atenolol had the opposite effect on each of these lipid values with the differences between the treatment groups being significant. Doxazosin was well tolerated and was shown to be effective as monotherapy in mild and moderate hypertension. Its effect on blood lipids was potentially favourable, and it should therefore be regarded as an alternative first-line drug in hypertensive patients.