DIURETICS OR ~-BLOCKERS FOR HYPERTENSION7

Treatment fo r hypertension usually starts with a thiazide d iuretic or a ~-adrenerg ic blocking agent; then the 2 are combined if ei ther alone is insufficient. Because thiazides cause hyperuricaemia and occasionally hyperglycaemia and hypokalaemia, caution has been advised in their long term use. It Ilas been suggested that ~-blockers a re preferable because they may reduce the risk of myocardial infarction. These drugs seem very safe , except in pat ients with heart failure or airways obstruction, and have become more popular, but they are expensive. Perhaps thiazides should remain the drugs of fi rst choice if they can be shown 10 be a<; safe.

A recent comparison by Berglund and Andersson o f the metabolic effects of bendrofluazide and propranolol (see p.l O)suggests that the side effects ofthi azides have been exaggerated and recommends their use in prererence to ~-blockers. Is this justified? In patients with normal plasma potassium the risk or hy(X)kalaemia wi th diuretics is small, but plasma electrolytes should be estimated occasionally. Thiazides and someti mes ~-blockers cause hyperglycaemia in hypertensive patients, but in the Berglund study glucose tolerance remained normal. Evidence o r altered gl ucose tolerance w ith thiazides, however, cannot yet be dismissed, although fortunately the reported deterioration is smaJl and any slight r isk is more than oIT:;d uy 001111"01 o f BP iIi fliiti"iilS -';; i.h moderate hypertension. Thiazides and ~-blockers both cause hyperuricaemia, and possibly small changes in plasma lipids.

'If a case is made fo r t reatment of mild hypertension, and if screening for petients with symptomless hypertension incre ases, many otherwise fit people will find themselves on long -term trsatment .. , At present, with little to choose between them Ithiazides and ~ -blockersL thiazides are t he logical c hoice because they are cheaper, '

Editorial : Unce\ I· 763 (4 Apr 1981)

4 INPHARMA 18 Apo- l 98\ 0156- 2703/ 81 / 0418-0004 $00.50/ 0 C ADIS Press