Discrepancies between clinic and ambulatory blood pressure responses to cilazapril therapy

To evaluate the antihypertensive effects of cilazapril, a new angiotensin-converting enzyme inhibitor, on clinic and ambulatory blood pressure (ABP) after first and last dose administrations.

Four weeks randomized, double-blind, controlled trial of three regimens.

Six hypertensive research clinics in Canada.

After a two-week placebo run-in period, 130 patients aged 22 to 77 years with mild to moderate essential hypertension were randomized and evaluated. Exclusion criteria were secondary hypertension, childbearing potential and other significant diseases.

Patients were assigned to cilazapril 2.5 mg (44 patients), cilazapril 5 mg (42) or placebo (44). Fourteen patients in each group were further evaluated in a substudy by 24 h ABP monitoring.

Cilazapril in either dosage induced significant and similar antihypertensive effects on clinic blood pressure shortly after dosing (2 to 4 h), persisting during chronic treatment; however, no relevant effect persisted at the end of dosing (24 h). After four weeks, at the end of dosing, 22, 24 and 38% of patients were clinical responders (decrease in sitting diastolic blood pressure 10 mmHg or greater) on placebo, 2.5 or 5 mg (differences not significant). Conversely, both cilazapril regimens induced similar and significant (P < 0.01) falls in mean 24 h ABP compared with placebo. Moreover, 7, 50 and 48% of patients exhibited a reduction in mean 24 h diastolic blood pressure 10 mmHg or greater on placebo, cilazapril 2.5 or 5 mg, respectively. Furthermore, both regimens induced adequate trough:peak ratios on ABP.