A study of the effects of lisinopril when used in addition to atenolol

A double-blind, parallel group multicentre study was carried out to compare the effects of adding once daily treatment with lisinopril 10 or 20 mg and placebo to the treatment of 100 patients whose blood pressure was inadequately controlled with once daily atenolol 50 mg. Following a two-week run-in period, patients with a lying DBP between 95 mmHg and 115 mmHg were randomised to either lisinopril 10 mg or placebo once daily for four weeks. Blood pressure measurements were made approximately 24 h after the previous dose of study medication. After four weeks' treatment the dose of study medication was doubled for those patients whose lying DBP was greater than or equal to 90 mmHg and a final assessment was made after a further two weeks of treatment. Overall, six weeks' treatment with lisinopril produced a greater fall in lying blood pressures than placebo when added to atenolol therapy. The difference in favour of the additional ACE inhibitor therapy was 7.1 +/- 2.6/5.4 +/- 1.5 mmHg (mean +/- SEM) (P less than 0.01). Standing blood pressures showed similar behaviour in favour of the additional ACE inhibitor treatment (7.6 +/- 2.4/4.7 +/- 1.6 mmHg) (P less than 0.005). Heart rate was not altered significantly by either lisinopril or placebo treatment. The addition of lisinopril to treatment with atenolol produced a slight increase in the reported number of adverse events compared with placebo. The results of this study indicate that the addition of lisinopril 10-20 mg once daily to treatment with a beta-adrenoceptor blocking drug produces a worthwhile decrease in blood pressure in patients not responsive to beta-blocker therapy alone.