Reviewed on 8/18/2021

What Is Chlorthalidone and How Does It Work?

Chlorthalidone is a prescription drug used to treat high blood pressure (hypertension). Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems. It is also used to reduce extra salt and water in the body caused by conditions such as heart failure, liver disease, and kidney disease. Decreasing extra salt and water in the body helps to decrease swelling (edema) and breathing problems caused by fluid in the lungs. Chlorthalidone is a "water pill" (diuretic). It increases the amount of urine you make, especially when you first start the medication. It also helps to relax the blood vessels so that blood can flow more easily.

  • Chlorthalidone is available under the following different brand names: Hygroton, Thalitone, and Chlorthalid.

What Are Dosages of Chlorthalidon?

Dosages of Chlorthalidone:


  • 15 mg
  • 25 mg
  • 50 mg
  • 100 mg

Dosage Considerations – Should be Given as Follows:


Adult and Geriatric:

  • 25-100 mg/day orally; usual range, 12.5-25 mg/day

Pediatric (off-label):

  • 0.3 mg/kg/day orally initially, may be increased to 2 mg/kg/day; not to exceed 50 mg per day


Adult and Geriatric:

  • 50-100 mg/day orally or 100 mg orally every other day; not to exceed 200 mg/day



  • 12.5-25 mg/day orally or 12.5-25 mg orally every other day; dosages greater than 25 mg/day offer an only minimal advantage

Dosing Considerations

Administered in the morning with food

Overdose management

Dosing Modifications

Renal impairment

  • Creatinine clearance under 10 ml/min: ineffective, do not use
  • Creatinine clearance over 10 ml/min: dose adjustment not necessary



How to Lower Blood Pressure: Exercise Tips See Slideshow

What Are Side Effects Associated with Using Chlorthalidone?

Side effects of chlorthalidone include:

Rare side effects of Chlorthalidone include:

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

What Other Drugs Interact with Chlorthalidone?

If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

Chlorthalidone has no known severe interactions with other drugs.

Serious interactions of chlorthalidone include:

  • aminolevulinic acid
  • amisulpride
  • cisapride
  • isocarboxazid
  • methyl aminolevulinate
  • squill
  • tretinoin
  • tretinoin topical

Chlorthalidone has moderate interactions with at least 154 different drugs.

Chlorthalidone has minor interactions with at least 147 different drugs.

This information does not contain all possible interactions or adverse effects. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns, or for more information about this medicine.

What Are Warnings and Precautions for Chlorthalidone?


  • This medication contains chlorthalidone. Do not take Hygroton, Thalitone, or Chlorthalid if you are allergic to chlorthalidone or any ingredients contained in this drug.

Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center immediately.


  • Documented hypersensitivity to chlorthalidone or sulfonamides
  • Failure of the kidneys to produce urine (anuria)

Effects of Drug Abuse

  • No information available

Short-Term Effects

  • See "What Are Side Effects Associated with Using Chlorthalidone?"

Long-Term Effects

  • See "What Are Side Effects Associated with Using Chlorthalidone?"


  • Use with caution in diabetes mellitus, fluid or electrolyte imbalance, excess of cholesterol (hypercholesterolemia), excess of uric acid in the blood (hyperuricemia) or gout, low blood pressure (hypotension), systemic lupus erythematosus, liver disease, severe renal disease, advanced age, history of allergy or bronchial asthma.
  • Avoid concurrent use with lithium (reduction of lithium dosage by 50% may be necessary).
  • May aggravate digitalis toxicity.
  • Patients allergic to sulfa drugs may show cross-sensitivity.
  • Risk of male sexual dysfunction.
  • Photosensitization may occur.
  • Electrolyte disturbances (low blood potassium level (hypokalemia), low blood sodium level (hyponatremia), low blood chloride ion level (hypochloremic alkalosis) may occur.

Pregnancy and Lactation

  • Chlorthalidone use during pregnancy may be acceptable. Either animal studies show no risk, but human studies are not available or animal studies showed minor risks, and human studies are done and showed no risk.
  • Expert analysis suggests the use of chlorthalidone only in LIFE-THREATENING emergencies when no safer drug is available. There is positive evidence of human fetal risk. Possible hazards include fetal or neonatal jaundice, thrombocytopenia, and other adverse reactions that have occurred in adults.
  • Chlorthalidone enters breast milk; it is not recommended when breastfeeding. The American Academy of Pediatrics states that chlorthalidone is compatible with breastfeeding.


Salt and sodium are the same. See Answer
Medscape. Chlorthalidone.
RxList. Thalitone Side Effects Center.

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