Abstract

Current 4-page advertisements¹ for the diuretic xipamide (Diurexan - Merck) which we discussed last year² cite “IMPORTANT NEW EVIDENCE (that) it is ‘as effective as many β-blockers but without their side effects, and produces better control of blood pressure throughout the whole day and night’”. This quotation comes from workers at Northwick Park³ and is accompanied by a photograph of the Clinical Research Centre. It is true that in their study the drug appeared to reduce blood pressure to much the same degree as β-blockers throughout the 24-hour cycle. But there is no reason to believe that xipamide differs from any other diuretic in its anti-hypertensive effect. As we noted some years ago, a thiazide diuretic alone can control even severely raised blood pressure in some patients.⁴ The advertising gives no prominence to the finding at Northwick Park (and elsewhere) that xipamide can cause a disturbing fall in the serum potassium concentration, and might thus be unsuitable for long-term anti-hypertensive therapy. It has still not been shown to have any advantage over other diuretics in the treatment of hypertension,² and is relatively expensive.