1. The effects of hypotensive therapy with three separate diuretics, methyldopa and clonidine were separately assessed.
2. All the treated groups showed a significant drop in blood pressure.
3. Polythiazide and hydrochlorothiazide each produced a significant fall in total peripheral resistance, whereas chlorthalidone did not.
4. Symptomless hypokalaemia was the only side effect seen with diuretics.
5. Methyldopa and clonidine reduced heart rate and cardiac index, but not total peripheral resistance.
6. The latter drugs also produced dry mouth, lassitude and drowsiness.