BETHANIDINE GUANETHIDINE AND METHYLDOPA IN TREATMENT OF HYPERTENSION - A WITHIN-PATIENT COMPARISON

In those patients who tolerated the drugs the control of the blood pressure on each drug was very similar (Tables III and IV). If a patient is able to tolerate methyldopa control of the blood pressure is more physiological, there being less postural and exercise hypotension on that drug (Tables IV and IX; Figs. 3 and 4). However, 6 of the 30 patients could not tolerate methyldopa, and one additional patient withdrew from the trial because of diarrhoea. The acceptability to the 24 patients tolerating methyldopa was the same as for all 30 patients on bethanidine, as judged by side-effect scores; and by patients' preference (Table VII) differences in favour of bethanidine were not significant (Tables VI and XIb). Tiredness is the most characteristic and troublesome side-effect with methyldopa, patients often not realizing how tired they are until they change to a different regimen. Bethanidine and guanethidine are qualitatively similar in their side-effects with the exception of the very high incidence of diarrhoea on guanethidine. As shown by side-effect scores (Tables VI and XIIc) or patients' preference (Table VII) guanethidine was much less popular with patients than the other two drugs. Bethanidine also differs from guanethidine in having a much shorter duration of action (Johnston et al.p1964). Guanethidine does produce less postural and exercise hypotension, but this difference is slight (Tables IV and XIIa; Fig. 2) and might not be regarded as of much clinical importance, though it achieves high statistical significance. It might be felt that the higher incidence of side-effects from guanethidine outweighs this advantage. In summary, methyldopa, provided it is tolerated, produces the best all-round blood pressure control of these three drugs, but 20% of our patients could not tolerate it. Bethanidine was tolerated by all patients, but brought slightly greater postural and exercise hypotension than guanethidine, which, however, produced the largest number of side-effects. © 1968, British Medical Journal Publishing Group. All rights reserved.