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Chlorthalidone

Brand names: Thalitone, Hygroton

Chlorthalidone is a long-acting water pill that lowers blood pressure and reduces fluid buildup.

Brand namesThalitone, Hygroton
Type of medicineThiazide-like diuretic (water pill)
Prescription?Prescription
ImportantThis page is general information, not a prescription. Don't start, stop, or change a medicine without talking to your provider or pharmacist.

Overview

It lasts longer than hydrochlorothiazide and is often preferred for blood pressure.

What it's used for

  • High blood pressure
  • Fluid buildup (edema)

How to take it

  • Take it once a day in the morning, with food if it upsets your stomach.

Your dose depends on your health and other medicines. Always follow your prescription label, and ask your pharmacist if anything is unclear.

Side effects

Common side effects

  • Peeing more
  • Dizziness
  • Low potassium or sodium
  • Higher uric acid or blood sugar
Call your provider todayMuscle cramps or weakness, extreme thirst, confusion, or an irregular heartbeat
Call your provider todaySudden painful, swollen joint (gout)
Call your provider todaySudden eye pain or blurry vision

Warnings

  • Your provider will check potassium, sodium, and kidney function.
  • Tell your provider if you're allergic to sulfa drugs.

Other medicines, foods, and alcohol

  • Lithium levels can rise.
  • NSAIDs weaken its effect.
  • Digoxin side effects are more likely with low potassium.

Tell your provider and pharmacist about every medicine, vitamin, and supplement you take.

Pregnancy and breastfeeding

Usually not a first choice in pregnancy. Talk with your provider.

Missed doses, overdose, and storage

If you miss a dose

Take it as soon as you remember, unless it's almost time for your next dose. Then skip the missed dose. Don't take two doses at once.

If someone takes too much

Call Poison Control at 1-800-222-1222 or get help online at poison.org. Call 911 if the person collapses, has a seizure, has trouble breathing, or can't be woken.

Storing it

Store at room temperature, away from heat and moisture (not in the bathroom), and out of reach of children and pets.

Conditions it's used for

Sources

Last updated 2026-11-13.