Drug Breakdown: METOLAZONE

02 April 2025
Volume 7 · Issue 4
blister packs or prescription pads

Abstract

In this column, Sharon Rees aims to refresh knowledge and interest in some of the commonly used drugs in a series of posts on Bluesky. This month she is talking about #metolazone

Day 1: A potent long-acting oral thiazide-like diuretic, #metolazone was discovered in the 1970s. Can be used in combination with loop diuretics for acute heart failure where it may potentiate effect & is postulated to help with diuretic resistance. Mostly used short-term, but some require longterm management

Day 2: #metolazone is licensed in adults for oedema of heart failure or kidney disease, as well as hypertension. Licensed in the UK as Xaqua® as 5 mg divisible tablet (care re switching as imports had other strengths/differences in bioavailability). Dose is 2.5 to 5 mg daily a.m.

Day 3: #metolazone has good oral absorption;take same time daily relative to meal;cmax~1.5hrs. High Vd & protein binding. ~ 10% hydroxylated to inactive metabolites/some enterohepatic recycling. Most excreted unchanged in urine/ small % biliary excretion. T½ 8-10hrs. Note that states of oedema can affect bioavailability for #metolazone; monitor for response variability

Day 4: #metolazone inhibits NaCl symporter & thus Na reabsorption. The action is predominantly in distal tubule, increasing urine volume & reducing fluid accumulation. Also, some Na absorption inhibition occurs in proximal tubule. K+excretion may be less affected compared to other diuretics. #metolazone is believed not to induce the reninangiotensin-aldosterone system, which supports overcoming issues with diuretic resistance. Electrolyte monitoring required

Register now to continue reading

Thank you for visiting Journal of Prescribing Practice and reading some of our peer-reviewed resources for prescribing professionals. To read more, please register today. You’ll enjoy the following great benefits:

What's included

  • Limited access to our clinical or professional articles

  • New content and clinical newsletter updates each month