Drug interactions
Chlorthalidone + Tolvaptan
Severity: Major
Chlorthalidone and Tolvaptan: major interaction.
Last updated
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
Both agents increase urinary water and solute loss, raising the risk of excessive volume depletion, hypotension and electrolyte disturbances. Rapid rises in serum sodium with tolvaptan can be hazardous, and thiazide diuretics may add to that risk in hyponatremia.
What this interaction means in plain words
Chlorthalidone and Tolvaptan 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; Tolvaptan belongs to Endocrine.
Why it happens
Additive diuresis from V2 receptor antagonism (aquaresis) and distal tubular sodium chloride cotransporter inhibition.
What to do
Monitor serum sodium closely, particularly in the first 24 hours of tolvaptan therapy, as well as potassium, volume status and renal function. Consider holding the thiazide when starting tolvaptan for hyponatremia.
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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Other interactions of Chlorthalidone
Other interactions of Tolvaptan
- Atazanavir + Tolvaptan Contraindicated
- Ceritinib + Tolvaptan Contraindicated
- Cobicistat + Tolvaptan Contraindicated
- Conivaptan + Tolvaptan Contraindicated
- Darunavir + Tolvaptan Contraindicated
- Idelalisib + Tolvaptan Contraindicated
Frequently asked questions
Can I take Chlorthalidone with Tolvaptan?
MediHelp rates the interaction as major. Chlorthalidone and Tolvaptan 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. Both agents increase urinary water and solute loss, raising the risk of excessive volume depletion, hypotension and electrolyte disturbances. Rapid rises in serum sodium with tolvaptan can be hazardous, and thiazide diuretics may add to that risk in hyponatremia.
How serious is the interaction between Chlorthalidone and Tolvaptan?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor serum sodium closely, particularly in the first 24 hours of tolvaptan therapy, as well as potassium, volume status and renal function. Consider holding the thiazide when starting tolvaptan for hyponatremia.
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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