Chlorthalidone
Tablet
Quick Summary
Chlorthalidone helps the kidneys remove extra salt and water.
Medical Uses
How it's taken
Usually taken in the morning so you don't have to get up at night to pass urine. Keep taking it even if you feel well, and don't stop suddenly without talking to your doctor.
Your doctor decides the right dose for you and how long to take it.
Your doctor decides the right dose for you. Follow their instructions and the label.
Common Side Effects
Passing more urine
Especially in the first hours.
Dizziness
From low blood pressure or salts.
Cramps
From low potassium or sodium.
Interactions
Other blood pressure medicines
Together they can lower blood pressure too much.
Lithium
Levels can rise.
Anti-inflammatory painkillers
Such as ibuprofen can reduce the effect and affect the kidneys.
Critical Warnings
Blood tests
Salt and kidney levels are checked regularly.
Dehydration
Take extra care in hot weather or with vomiting and diarrhoea.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Chlorthalidone: drug information(opens in a new tab) · MedlinePlus, US National Library of Medicine