Drug interactions
Chlorothiazide + Hydrochlorothiazide-losartan
Severity: Major
Chlorothiazide and Hydrochlorothiazide-losartan: 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
Using chlorothiazide with a hydrochlorothiazide-containing product duplicates thiazide therapy, increasing the risk of hypokalemia, hyponatremia, volume depletion and hypotension without clear added benefit.
What this interaction means in plain words
Chlorothiazide and Hydrochlorothiazide-losartan 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.
Chlorothiazide belongs to Cardiovascular; Hydrochlorothiazide-losartan belongs to Cardiovascular.
Why it happens
Duplicate inhibition of the distal tubule sodium-chloride cotransporter giving additive diuresis and electrolyte loss.
What to do
Avoid combining two thiazides and discontinue one. If unavoidable, monitor electrolytes, renal function and blood pressure.
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 Hydrochlorothiazide-losartan
- Aliskiren + Hydrochlorothiazide-losartan Contraindicated
- Dofetilide + Hydrochlorothiazide-losartan Contraindicated
- Hydrochlorothiazide-losartan + Sparsentan Contraindicated
- Aceclofenac + Hydrochlorothiazide-losartan Major
- Aldesleukin + Hydrochlorothiazide-losartan Major
- Amifostine + Hydrochlorothiazide-losartan Major
Other interactions of Chlorothiazide
Frequently asked questions
Can I take Chlorothiazide with Hydrochlorothiazide-losartan?
MediHelp rates the interaction as major. Chlorothiazide and Hydrochlorothiazide-losartan 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. Using chlorothiazide with a hydrochlorothiazide-containing product duplicates thiazide therapy, increasing the risk of hypokalemia, hyponatremia, volume depletion and hypotension without clear added benefit.
How serious is the interaction between Chlorothiazide and Hydrochlorothiazide-losartan?
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 combining two thiazides and discontinue one. If unavoidable, monitor electrolytes, renal function and blood pressure.
What other medicines interact with Hydrochlorothiazide-losartan?
MediHelp also lists interactions of Hydrochlorothiazide-losartan with, for example, Aliskiren, Dofetilide, Sparsentan. The full list is on the Hydrochlorothiazide-losartan page.
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