The haemodynamic and humoral effects of treatment for one month with the angiotensin converting enzyme inhibitor perindopril in salt replete hypertensive patients.

We have studied the effects of treatment for one month with perindopril, 4 or 8 mg once daily, in seven hypertensive patients. Blood pressure was lowered from 164/93 mm Hg to 145/84 mm Hg by 4 mg of perindopril and after one month remained at 142/82 mm Hg. Neither postural hypotension nor tachycardia occurred. Inhibition of plasma angiotensin converting enzyme (ACE) lasting for over 24 h was achieved and there was a significant increase in plasma renin activity (PRA). Maximum plasma concentrations of the active metabolite of perindopril, S-9780, were detected four h after oral administration. After treatment for one month there was evidence of reduced sensitivity of plasma ACE to the action of the inhibitor. The plasma concentration of S-9780 required to produce 50% inhibition of plasma ACE rose from 2.4 ng X ml-1 following the first dose to 5.5 ng X ml-1 after one month.