Captopril administered every three hours in difficult-to-control hypertension.

The renovascular hypertension of an elderly patient, which was controlled initially with standard-dose therapy with captopril, later responded only to 75 mg given every 3 h without side effects. Changeover to another class of antihypertensives, as is recommended in recalcitrant cases, was not needed. Convenient maintenance therapy with lisinopril (10 mg twice daily) has kept blood pressure under control for a year.