Comparison of the efficacy and tolerability of an angiotensin converting enzyme inhibitor (lisinopril) versus a calcium channel antagonist (diltiazem SR) in the treatment of moderate to severe hypertension.

One hundred and ten patients (mean age 50.6 years) with moderate to severe essential hypertension (DBP between 105 and 116 mmHg) were randomised to eight weeks of double-blind treatment with lisinopril (n = 56) or diltiazem SR (n = 54). Fourteen patients withdrew from therapy; six patients withdrew because of adverse events (lisinopril, n = 3; diltiazem SR, n = 1) and lack of BP control (lisinopril, n = 1; diltiazem SR, n = 1). Both monotherapies were titrated upward (lisinopril 20-40 mg daily, diltiazem SR 120-180 mg twice daily) to achieve an office DBP < 90 mmHg. Hydrochlorothiazide (HCTZ; 25 mg daily) was added to monotherapy after week 4 if patients did not reach the BP goal (i.e. non-responders). After four weeks of therapy, 72% of patients (74 of 103) were nonresponders. At eight weeks of therapy, 66 patients (lisinopril, n = 32; diltiazem SR, n = 34) had received HCTZ. At week 8, 53% of lisinopril and 36% of diltiazem SR patients met the response criteria. Mean office DBP decreased from baseline -18.1 +/- 8.6 mmHg for lisinopril patients and -15.9 +/- 10.1 mmHg for diltiazem SR patients at week 8. Lisinopril was as effective as diltiazem in reducing systolic and diastolic office BP at week 4 (p > 0.1). Likewise, at weeks 4 and 8, no statistically significant differences were detected between treatments (p > 0.05) for systolic and diastolic ambulatory BP averaged over 24 hours. Both treatments were well tolerated and showed important antihypertensive efficacy in patients with moderate to severe BP elevation.