VMnvpoillts The benefits still outweigh the risks for thiazides

Thiazide diuretics, with beta blockers, have been the first choice of antihypertensive therapy for many years. Acute thiazide therapy induces diuresis (useful in congestive heart disease), but long term thiazide therapy lowers peripheral vascular resistance, which is appropriate for antihypertensive therapy.

There has been recent controversy regarding the risk: benefit ratio of long term thiazide therapy. Hypokalaemia is a widely recognised adverse effect of thiazides, but its potential to lead to cardiac arrhythmias remains controversial. Increased serum LDL cholesterol levels have been reported with the use of thiazides, but most evidence suggests that these effects are transient. Other reported adverse effects include: impotence; sodium depletion, particularly in the elderly; worsening glucose tolerance, especially from long term therapy and/ or long acting agents; gout; and rashes.

Loop diuretics can also impair glucose tolerance and cause ototoxicity and gout. Concomitant NSAIDs may reduce the hypotensive effects of thiazides.

Thiazides have been linked to reduced hip fractures in elderly patients on long term therapy and decreased urinary calcium excretion.

'Overall, the risk: benefit ratio for thiazides still favours the drugs.'

Future thiazide therapy should aim to reduce dosages and to avoid hypokalaemia either through diet or potassium-sparing diuretics. Orme M. Thiazides in the 19905. British Medical Journal 300: 1668-1669. 30 Jun 1990,.~,

2 - 14 Jill 1990 INPHARMA® ISSN 0156-2703/90/0714-0012/0101.00/0 '" Adi! IlfurtUltiolflll Ltd