Metolazone

Sold as Zaroxolyn, Diulo, Mykrox. Every FDA application for this active ingredient: 3 branded and 14 generic.

As of Nov 15, 2026, FDA lists 17 applications for Metolazone (sold as Zaroxolyn, Diulo, Mykrox), first approved Nov 27, 1973, with 0 new uses approved and 0 published complete response letters.

First approved: Nov 27, 1973
Applications: 17
New uses approved: 0
Complete response letters: 0
Medicare spending, 2025: $12.7M

Medicare Spending

CMS Part D and Part B, 2025, before manufacturer rebates; matched by generic name

Product	Part	Spending, 2025	Change	Beneficiaries
Metolazone	Part D	$12.7M	-11%	202,137

What Pharmacies Pay

Median price per unit across package codes in CMS's weekly NADAC survey, Nov 11, 2026, before rebates; see every drug's price change

METOLAZONE 10 MG TABLET: $0.389 per unitGeneric · -4% in a year
METOLAZONE 2.5 MG TABLET: $0.226 per unitGeneric · +8% in a year
METOLAZONE 5 MG TABLET: $0.242 per unitGeneric · -21% in a year

Clinical Trials

6 open or ongoing studies name this ingredient as an intervention, including as a comparator; newest first. See all


Add-on Diuretics in Acute Decompensated Heart FailureAcute Decompensated Heart Failure · Tanta University	Phase 2	Recruiting	Jan 28, 2026
Comparative Efficacy and Safety of Acetazolamide Versus Metolazone as an Adjunct to Standard Therapy in Patients With Acute Decompensated Heart FailureAcute Decompensated Heart Failure, Heart Failure, Diastolic · University of Health Sciences Lahore	Not applicable	Recruiting	Sep 30, 2025
Acetazolamide or Metolazone in Acute Heart FailureHeart Failure Acute, Decompensated Heart Failure · Clinica Alemana de Santiago	Not applicable	Not yet recruiting	Feb 22, 2024
Diuretics vs. Afterload Reduction for Treatment of HeartLogic AlertsHeart Failure, Congestive · Heart Center Research, LLC	Phase 4	Recruiting	Jan 23, 2024
Optimal Diuretic Therapies for Acute Heart Failure With Volume OverloadAcute Heart Failure · Johannes Grand	Phase 3	Recruiting	Dec 12, 2023
Ertugliflozin in Chronic Heart FailureHeart Failure · Yale University	Phase 2	Recruiting	Jun 18, 2020

Applications

NDAs, BLAs and generic ANDAs for this ingredient, oldest first; each opens its full history


Nov 27, 1973	ZaroxolynNDA 17386 · New molecular entity	I3 Pharms	33	Discontinued
Feb 24, 1981	DiuloNDA 18535 · New formulation or manufacturer	Gd Searle LLC	5	Discontinued
Oct 30, 1987	MykroxNDA 19532 · New dosage form	Chartwell Molecular	15	Discontinued
Dec 19, 2003	MetolazoneANDA 76466	Sandoz	1	Marketed
Dec 19, 2003	MetolazoneANDA 76732	Sandoz	1	Marketed
Dec 23, 2003	MetolazoneANDA 76698	Mylan	4	Marketed
Dec 24, 2003	MetolazoneANDA 75543	Ani Pharms	0	Discontinued
Apr 29, 2004	MetolazoneANDA 76482	Roxane	0	Marketed
Jul 21, 2004	MetolazoneANDA 76891	Watson Labs	0	Discontinued
Dec 2, 2020	MetolazoneANDA 213251	Alembic	0	Marketed
Mar 30, 2021	MetolazoneANDA 213827	Innogenix	1	Marketed
Mar 30, 2021	MetolazoneANDA 214799	Unichem	0	Marketed
Aug 20, 2021	MetolazoneANDA 215184	Rubicon Research	0	Marketed
Oct 24, 2022	MetolazoneANDA 215616	Renata	0	Marketed
Oct 25, 2022	MetolazoneANDA 216216	Ne Rx Pharma	0	Marketed
Apr 17, 2024	MetolazoneANDA 218606	Acertis Pharms	0	Marketed
Nov 6, 2024	MetolazoneANDA 217563	Micro Labs	0	Discontinued

Applications, approvals and products come from FDA's Drugs@FDA data files, refreshed weekly, grouped by active ingredient as FDA spells it. Complete response letters are FDA's published letters. Medicare spending is CMS's Part D and Part B dashboard, matched to this ingredient by generic name; shortages are FDA's shortage list, matched by application number; clinical trials are ClinicalTrials.gov studies naming the ingredient as an intervention, refreshed daily; safety programs are FDA's REMS list, matched by application number or, for shared programs, by ingredient. Drugs@FDA