chlorthalidone vs metolazone
PlainMeds reviewed this comparison against our methodology in August 2026. It places FDA and CMS record fields side by side, without recommending either medication.
Side-by-side comparison of chlorthalidone and metolazone. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
Thalitone
Zaroxolyn
Chlorthalidone is a water pill that helps lower blood pressure and reduce swelling. It works by helping your kidneys remove extra salt and water from your body.
Metolazone is a water pill that helps your body get rid of extra salt and water. It can also lower blood pressure.
This medicine treats high blood pressure, either alone or with other drugs. It also helps with swelling from heart failure, liver problems, or kidney problems. Sometimes, it's used for swelling caused by steroid or estrogen treatments.
Metolazone treats water retention (edema) caused by heart failure or kidney problems. This includes conditions like nephrotic syndrome or reduced kidney function. It also treats high blood pressure, and can be used alone or with other blood pressure medicines. A faster-acting form of metolazone (Mykrox) is for new patients with mild to moderate high blood pressure.
Chlorthalidone is a diuretic, which means it helps your body get rid of extra fluid. It works by acting on your kidneys to increase the amount of salt and water that you pass in your urine. This helps to lower your blood pressure and reduce swelling.
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.
- • Loss of appetite
- • Upset stomach
- • Nausea
- • Vomiting
- • Cramps
- • Dizziness
- • Lightheadedness
- • Drowsiness
- • Fatigue
- • Weakness
- Fatigue 861
- Nausea 704
- Diarrhoea 643
- Dizziness 563
- Pain 541
- Dyspnoea 1,204
- Death 867
- Acute Kidney Injury 790
- Nausea 736
- Renal Failure 713
If you have kidney problems where you aren't producing urine, you should not take this medicine. Also, if you are allergic to chlorthalidone or other sulfa drugs, avoid this medication.
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.
Using water pills when you are otherwise healthy during pregnancy is not a good idea and could be risky for you and your baby. If you have swelling during pregnancy, try raising your legs and wearing support hose first. Talk to your doctor before taking this medicine while pregnant.
Using diuretics during pregnancy can expose the mother and fetus to unnecessary risks. Talk to your doctor about the risks and benefits of taking metolazone while pregnant or breastfeeding. It should only be used if medically necessary.
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How to Read This chlorthalidone vs metolazone Comparison
chlorthalidone is classified in the Thiazide-Like Diuretic drug class, while metolazone sits within the Thiazide-Like Diuretic class. Because both drugs share the same classification, they are often considered interchangeable in theory, but clinical outcomes rarely track that cleanly. Both drugs are prescription-only, so a licensed provider must authorize use.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, chlorthalidone has 3,312 submissions while metolazone has 4,310. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. No direct interaction between these two drugs is listed in our FDA-derived dataset, though co-prescription still warrants pharmacist review. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.
A table cannot represent individual circumstances. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This registry does not provide medical, treatment, substitution, or medication-change directions for chlorthalidone or metolazone.
Registry boundary: This comparison displays source-record fields and does not provide individualized medical direction.