Antihypertensive Dose Reduction is Favoured Over Therapy Withdrawal For maintaining BP control in the long term treatment of hypertension

It has been suggested that the dose requirement for antihypertensive medication decreases during long term therapy. Complete discontinuation of antihypertensive treatment has been tried with little success but few trials have tested dosage reduction as a possible alternative to drug discontinuation. In a double-blind trial, diastolic BP was maintained at < 90mm Hg for 6 months in 606 men with mild to moderate hypertension using 1 of 4 regimens: hydrochlorothiazide 25mg bid (group 1 ); hydrochlorothiazide 50mg bid (group 2); hydrochlorothiazide 50mg bid + low dose step II drug (propranolol, clonidine, reserpine; group 3); or hydrochlorothiazide 50mg bid + high dose step II drug (group 4). Two-thirds of patients, were then randomised to either progressive dose reduction or drug discontinuation depending on treatment group and response. The remaining patients constituted control groups.

Although 55% of group 1 patients maintained goal BP within 6 months of discontinuation of treatment, significantly better results were attained in the fully treated control patients. In group 2, the proportion of patients maintaining BP control after 6 months did not differ between control patients and those who received low dose hydrochlorothiazide. Withdrawal of the step II agent in groups 3 and 4 resulted in significantly reduced BP control compared with fully treated patients. The frequency of adverse effects did not differ between treatment groups.

'The present results suggest that after long·term treatment, dosage reduction is more effective in preserving antihypertensive coniroi ihan is discontinuation of medications' and further reduces the risk of adverse effects and treatment cost. Freis ED, Thomas JR, Fisher SG, Hamburger R, Borreson RE, et al. Effects of reduction 1n drugs or dosage after long-term control of systemic hypertension. American Journal of Cardiology 63:702-708, Mar 1989 9067

0156-2703j89j0422-0009j0$01.00j0 © ADIS Press INPHARMA® 22 Apr 1989 9