EFFICACY AND SAFETY OF THE 200-300-MG SUSTAINED-RELEASE FORMULATION OF DILTIAZEM ADMINISTERED ONCE-DAILY IN PATIENTS WITH STABLE ANGINA

The aim of this multicentre randomised double blind study was to compa re the efficacy and safety of the 200-300 mg sustained release diltiaz em formulation administered once daily (200-300 SR) with standard dilt iazem (D) given three or four times daily to patients with stable angi na. Patients aged 59 years, with a reproducible exercise test on place bo, were randomised to 4 weeks of treatment with 200-300 SR (n = 70) o r D (n = 74). The initial dosage was 200 mg in the 200-300 SR group an d 60 mg t.i.d. in the D group, increased to 300 mg once daily or 60 mg q.i.d., respectively, if ergometric parameters, which were always mea sured at the end of the dosing period, had not improved after two week s. After 4 weeks of treatment, the antianginal efficacy at rest was co mparable in the 200-300 SR and the D group; there was a prolongation o f the total duration of exertion of 14 % and 18 % respectively (P < 0. 01 vs placebo for bath groups with no intergroup difference). A dose-e ffect relation was found with both formulations. The 200-300 SR formul ation gave full 24 hour antiischaemic protection when administered onc e daily. Its efficacy and safety were comparable to those of standard diltiazem t.i.d. or q.i.d. in patients with stable angina. The once da ily administration should improve treatment compliance.