1. Although it is now easy to treat most patients with hypertension without producing troublesome side effects, a few patients remain refractory to conventional methods of treatment. These patients will progress to die of renal failure unless the blood pressure is controlled.
2. Thiazides potentiate the effect of other hypotensive agents and this potentiation is probably independent of their diuretic action. Diazoxide actually produces salt and water retention at the same time as marked decrease in the blood pressure. Spirono-lactone in a dose of 400 mg daily produced a highly significant reduction in blood pressure in an unselected group of patients with severe refractory hypertension.
3. β-Adrenergic blocking agents either alone or in combination with other drugs may be useful in the control of severe hypertension. An increasing effect on the blood pressure was demonstrated with doses between 1 and 2 g per day.
4. A new drug, prazosin hydrochloride, with properties somewhat similar to hydrallazine but with few side effects promises to be useful in the control of severe refractory hypertension particularly in combination with β-adrenergic blocking drugs.