Addendum: Metolazone is now available in an unlicensed preparation. Some centres may consider using the newly available preparation in preference to bendroflumethiazide, particularly in patients with a very low GFR.
Sanofi-Aventis has ceased to manufacture and distribute metolazone. Metolazone is sometimes used for patients with heart failure and intractable fluid retention as an adjunct to loop diuretics as part of 'sequential nephron blockade'.
Most studies of combination therapy (loop+thiazide) have used metolazone, but Channer showed that metolazone and bendrofluazide were equally effective in inducing diuresis in patients with resistant oedema when added to intravenous frusemide.*
Our advice is to switch patients receiving metolazone to bendroflumethiazide when a patient's supplies run out, at a dose of 2.5 mg, increasing to 5mg, if indicated.
An unlicensed preparation is available at significantly increased cost. The old preparation came as 5mg tablets however the non-licensed preparations may come as 2.5mg tablets. Generic manufacturers may step into the breach, and metolazone is likely to become available again in the UK in the future.
*Channer KS, McLean KA, Lawson-Matthew P, Richardson M. Combination diuretic treatment in severe heart failure: a randomised controlled trial. Br Heart J 1994;71:146-150