Drug interactions
Chlorthalidone + Lithium
Severity: Major
Chlorthalidone and Lithium: major interaction.
Last updated Sources: Health Canada product monograph
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Chlorthalidone reduces renal lithium clearance and can raise serum lithium concentrations into the toxic range. Toxicity presents with tremor, confusion, ataxia, vomiting and, in severe cases, seizures or renal damage.
What this interaction means in plain words
Chlorthalidone and Lithium can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Chlorthalidone belongs to Cardiovascular; Lithium belongs to Central Nervous System.
Why it happens
Thiazide-induced sodium depletion increases proximal tubular reabsorption of lithium, decreasing its renal elimination.
What to do
Avoid if possible; if used, reduce the lithium dose and measure serum lithium within the first week and after any dose change. Teach patients to recognize toxicity signs and maintain consistent sodium and fluid intake.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Chlorthalidone
Other interactions of Lithium
- Lithium + Thioridazine Contraindicated
- Lithium + Vandetanib Contraindicated
- Aceclofenac + Lithium Major
- Acemetacin + Lithium Major
- Amisulpride + Lithium Major
- Amlodipine-benazepril + Lithium Major
Frequently asked questions
Can I take Chlorthalidone with Lithium?
MediHelp rates the interaction as major. Chlorthalidone and Lithium can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Chlorthalidone reduces renal lithium clearance and can raise serum lithium concentrations into the toxic range. Toxicity presents with tremor, confusion, ataxia, vomiting and, in severe cases, seizures or renal damage.
How serious is the interaction between Chlorthalidone and Lithium?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid if possible; if used, reduce the lithium dose and measure serum lithium within the first week and after any dose change. Teach patients to recognize toxicity signs and maintain consistent sodium and fluid intake.
What other medicines interact with Chlorthalidone?
MediHelp also lists interactions of Chlorthalidone with, for example, Amifostine, Atenolol-chlorthalidone, Candesartan-hydrochlorothiazide. The full list is on the Chlorthalidone page.
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