Guanadrel sulfate compared with methyldopa for mild and moderate hypertension.

In a two-year study of 547 hypertensive patients receiving diuretics, the addition of guanadrel sulfate or methyldopa reduced elevated blood pressure to a similar degree and provided good control in 70% of the patients. Guanadrel-treated patients experienced less frequent and less severe drowsiness than methyldopa-treated patients. The frequency of morning orthostatic faintness was low and similar in both treatment groups. Guanadrel produced no tissue toxicity. Guanadrel sulfate, a postganglionic sympathetic inhibitor, is nearly free of central nervous system side effects and is recommended over methyldopa for step 2 therapy when diuretics alone fail to control mild or moderate hypertension.