A randomised crossover comparison of reserpine and sustained-release nifedipine in hypertension

Abstract

Objective: To compare the effectiveness of the combination of hydrochlorothiazide (HCT) plus sustained-release nifedipine with the combination of HCT plus reserpine in lowering high blood pressure (BP) unresponsive to HCT monotherapy.

Design: An open, randomised crossover drug trial.

Setting: Outpatients' clinic in Parirenyatwa Hospital, Harare, a tertiary referral centre.

Subjects: 32 Black patients of both sexes with newly diagnosed or previously treated hypertension aged between 21 and 65 years who had a BP > 140/95 after receiving HCT 25 mg daily for four weeks were studied.

Intervention: Patients were kept on HCT 25 mg daily and were randomised to receive either reserpine 0.25 mg daily or nifedipine (Adalat Retard) 20 mg bd for four weeks. This was followed by a two week washout period during which patients received HCT 25 mg daily only. After the washout period patients were crossed over to the alternative treatment for four weeks. Patients were kept on HCT 25 mg daily throughout the trial.

Main outcome measures: The main outcome measure was the fall in BP which was taken as the difference between the BP at baseline and the BP at the end of each treatment period. Both systolic blood pressure (SBP) and diastolic blood pressure (DBP) measurements were taken.

Results: Both second line drugs were effective in lowering SBP and DBP and there was no significant difference between them. Nifedipine reduced SBP by 18.9 mmHg (95% CI 12.1 to 25.7) and DBP by 9.6 mmHg (95% CI 7.2 to 12.0). Reserpine reduced SBP by 15.9 mmHg (95% CI 8.4 to 23.4) and DBP by 11.1 mmHg (95% CI 7.5 to 14.6). However, only two patients attained the target DBP of < or = 90 mmHg after each active treatment period.

Conclusion and recommendations: Since both agents were equally effective in reducing both SBP and DBP and reserpine is much cheaper than nifedipine, it is recommended that for a developing country like Zimbabwe, the combination of HCT and reserpine at the above doses should be used as the first step to treat mild to moderate hypertension without evidence of end organ damage. However, further trials should compare BP lowering effects as well as end organ protection offered by the trial drugs.