Nifedipine has been used in hypertension, mainly as a third-line drug for rapid blood pressure reduction, for over 10 years. More recently it has been shown to be effective and safe in reducing mild to moderate blood pressure when used alone in a slow release formulation. A placebo-controlled study investigating the efficacy and safety of nifedipine in comparison with cyclopenthiazide-potassium has now been carried out by 4 general practitioners in the Glasgow area. Ninety-four patients were entered into the study. After a 4-week placebo run-in phase, patients were randomly allocated to receive either slow-release nifedipine 20 mg b.d., or cyclopenthiazide 0.25 mg with 8.1 mmol potassium daily. The dose was doubled at week 8 for non-responders, and at week 12 the alternative drug was added if there was still no response. The patients were studied for up to 28 weeks. Nifedipine was found to have similar blood pressure lowering efficacy to cyclopenthiazide-potassium, but withdrawals from nifedipine due to side-effects at an early stage were more common.</p
