New sustained-release nifedipine formulation in treatment of essential hypertension. Unidipin Cooperative Study Group.

Sustained-release nifedipine (SR) (developed by Elan, Athlone, Ireland; Unidipin is the tradename of Nifedipine SR, registered by Farmitalia Carlo Erba SpA, Milano, Italy) is a new nifedipine formulation suitable for once-daily administration. In a double-blind, randomized study of 269 hypertensive subjects, nifedipine SR efficacy and tolerability were investigated in comparison with the conventional twice-daily nifedipine tablet formulation. After a 3-week placebo phase, patients were titrated to 50-100 mg once daily nifedipine SR or 20-40 mg twice daily (b.i.d.) of the reference treatment. Significant and comparable reductions in systolic and diastolic blood pressures (SBP, DBP) during supine rest and on standing were observed in the two groups during and at the end of 3-month treatment. At the last visit, supine BP reductions of 17 +/- 17.7/14.8 +/- 8.8 mm Hg 24 h after nifedipine SR and of 21.7 +/- 19/16.1 +/- 9 mm Hg 12 h after the conventional tablet were measured. The numbers of patients achieving the goal BP reduction were comparable. There were no significant differences between treatments in the nature and severity of adverse events. Long-term efficacy and safety of the new formulation were investigated in patients receiving treatment for 12 months. After the initial significant reduction, the patients' BP showed a trend to a further less pronounced decrease for the remainder of the study. In only two patients was the dose readjusted during long-term administration. No serious side effects or alterations of laboratory tests occurred. Nifedipine SR is effective and safe therapy for elevated BP, with advantages in terms of patient acceptability.