Prescription medication · Thiazide-Like Diuretic
metolazone
Also sold as Zaroxolyn. Metolazone treats water retention (edema) caused by heart failure or kidney problems.
Data updated 2026-05-15
- 10,872
- FDA reportsModerately reported
- $0.43
- Generic price (NADAC)
metolazone (Zaroxolyn) is a prescription Thiazide-Like Diuretic. Metolazone treats water retention (edema) caused by heart failure or kidney problems.
Metolazone is a water pill that helps your body get rid of extra salt and water. It can also lower blood pressure.
Verify with FDA → · CMS NADAC pricing →
Drug Pricing (NADAC)
Generic Price
$0.43/unit
Generic Available
Yes (10 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
NADAC price trail: METOLAZONE 10 MG TABLET
Same CMS presentation as the headline generic unit price above (2 effective dates). Adjacent % compares consecutive NADAC releases for this description only, not a patient out-of-pocket quote. Latest step: +5.5% vs prior release.
| Effective | NADAC / unit | vs prior | NDCs |
|---|---|---|---|
| October 23, 2024 | $0.4089/EA | - | 1 |
| December 18, 2024 | $0.4314/EA | +5.5% | 8 |
What it does
Metolazone treats water retention (edema) caused by heart failure or kidney problems.
Common side effects
Dizziness, Lightheadedness, Drowsiness
Key warnings
If you have trouble urinating, are in a hepatic coma or precoma, or are allergic to metolazone, you should not take this medicine.
The sections below are summarized in plain English from metolazone's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Metolazone is a diuretic, which means it helps your kidneys remove salt and water from your body. This reduces the amount of fluid in your blood vessels, which can lower blood pressure and reduce swelling. It belongs to a class of drugs called thiazide-like diuretics.
Side Effects (from patient reports)
Based on 10,872 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for metolazone, by number of reports
- Dyspnoea
Dyspnoea
1,204 reports
- Death
Death
867 reports
- Acute Kidney Injury
Acute Kidney Injury
790 reports
- Nausea
Nausea
736 reports
- Renal Failure
Renal Failure
713 reports
- Cardiac Failure Congestive
Cardiac Failure Congestive
674 reports
- Fatigue
Fatigue
648 reports
- Diarrhoea
Diarrhoea
639 reports
- Dizziness
Dizziness
600 reports
- Chronic Kidney Disease
Chronic Kidney Disease
589 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for metolazone each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where metolazone sits
metolazone has more FDA adverse-event reports than 41% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is metolazone; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 10,872 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2003–2025.
Total Reports
10,872
Reports Mentioning Death
2,165
19.9% of reports — not proof of cause
Hospitalization Reports
5,657
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | DYSPNOEA | 1,204 |
| 2 | DEATH | 867 |
| 3 | ACUTE KIDNEY INJURY | 790 |
| 4 | NAUSEA | 736 |
| 5 | RENAL FAILURE | 713 |
| 6 | CARDIAC FAILURE CONGESTIVE | 674 |
| 7 | FATIGUE | 648 |
| 8 | DIARRHOEA | 639 |
| 9 | DIZZINESS | 600 |
| 10 | CHRONIC KIDNEY DISEASE | 589 |
| 11 | HYPOTENSION | 579 |
| 12 | ASTHENIA | 572 |
| 13 | HEADACHE | 537 |
| 14 | OEDEMA PERIPHERAL | 524 |
| 15 | FALL | 507 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
If you have trouble urinating, are in a hepatic coma or precoma, or are allergic to metolazone, you should not take this medicine. Using diuretics when pregnant can be dangerous to the baby. Only use this medicine during pregnancy if absolutely necessary for a medical condition.
Common Questions
Can I take metolazone if I'm pregnant?
What should I do if I feel dizzy after taking metolazone?
How long does it take for metolazone to start working?
Can I drink alcohol while taking metolazone?
What if I miss a dose?
Does metolazone interact with other medications?
Can metolazone cause dehydration?
How often will I need blood tests?
Can I stop taking metolazone suddenly?
What are the ingredients in metolazone tablets?
What are the common side effects of metolazone?
What drug class is metolazone?
What pregnancy or breastfeeding source fields are listed for metolazone?
Related Medications in Thiazide-Like Diuretic
Other drugs grouped near metolazone - same-class peers and common alternatives.
acebutolol
Sectral
Acebutolol is a medicine that helps lower blood pressure and control irregular heartbeats.
Compare with metolazone →
aliskiren
Tekturna
Tekturna is a medicine used to treat high blood pressure.
Compare with metolazone →
amiloride
Midamor
Amiloride is a water pill that helps your body hold onto potassium.
Compare with metolazone →
amlodipine
Norvasc
Amlodipine (Norvasc) is a drug that lowers blood pressure and treats chest pain.
Compare with metolazone →
amlodipine/benazepril
Lotrel
Lotrel is a combination medicine that contains amlodipine and benazepril.
Compare with metolazone →
Compare beyond drug class
Nationwide peers by FAERS volume & death-report share
Two PlainMeds-derived comparison paths for metolazone: nearest FDA FAERS report volume and nearest death-report share among drugs with at least 1,000 logged reports, excluding same-class neighbors listed above. Counts reflect reporting volume, not proven individual harm.
Similar FAERS report volume
Nearest drugs by total FAERS reports. This record: 10,872.
Similar death-report share
Nearest drugs by FAERS death-report share. This record: 19.91%.
- vancomycin Δ 0.06 pts · 55,549 reports · Glycopeptide Antibiotic 19.85%death share
- temazepam Δ 0.14 pts · 36,917 reports · Benzodiazepine (Hypnotic) 20.06%death share
- itraconazole Δ 0.22 pts · 11,311 reports · Azole Antifungal 19.69%death share
- enzalutamide Δ 0.30 pts · 57,614 reports · Androgen Receptor Inhibitor 19.61%death share
Medication Guides
Understanding Drug Interactions
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Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
Narrow Therapeutic Index Drugs
FDA bioequivalence and label-record context for narrow therapeutic index medicines
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
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What the FDA Data Shows for metolazone
The FDA label for metolazone (sold under brand names such as Zaroxolyn) classifies it as a prescription-only medication in the Thiazide-Like Diuretic class. Metolazone treats water retention (edema) caused by heart failure or kidney problems. Official labeling lists 7 commonly reported side effects, including Dizziness, Lightheadedness, Drowsiness.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 10,872 voluntary reports. Interaction data is drawn directly from FDA-approved prescribing information. NADAC pricing from CMS shows a generic unit cost of $0.43.
Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information are separate source-record fields. This page is a public FDA/CMS registry and does not provide medical, treatment, substitution, or medication-change directions.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. This registry does not provide medication decisions.
Last updated: December 24, 2024
PlainMeds is rendered directly from FDA openFDA/FAERS extracts, DailyMed labels, and CMS drug-pricing files, no number is typed in by an editor. FAERS counts, recalls, shortages, and price figures on this page are queried live from those federal extracts. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-05-15. Primary sources: openFDA / FAERS, DailyMed and CMS Part B ASP.
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled from the source snapshot dated . See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a data issue.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages