1. Twelve patients with essential hypertension were treated aggressively with minoxidil in order to achieve blood pressure control as rapidly as possible.
2. After an initial dose of 5 mg, dose increments were administered 6 hourly until a fall in blood pressure was observed.
3. The size of additional doses was determined by the magnitude of and response to the lowest effective dose and the therapeutic objective.
4. Over a time-interval of 24–42 h blood pressure was reduced to normal or near normal in each case.
5. Analysis of the relationship between blood pressure response and cumulative dose indicates that at sub-optimum blood pressure responses it is safe and efficacious to give half the antecedent cumulative dose as a single dose in arriving at the therapeutic objective.