Abstract

Metolazone (Metenix 5 - Hoechst) is a quinazoline sulphonamide diuretic related to quinethazone. We discussed its diuretic properties four years ago (when the trade name was Zaroxolyn)¹ and concluded that it was probably more effective than thiazides and had a longer duration of action than frusemide. Metolazone is now also promoted specifically as an antihypertensive diuretic. It is claimed that metolazone is a long-acting ‘extremely effective’ antihypertensive; if this is true it would have an advantage over the thiazide diuretics, which also lower arterial pressure.²