Drug interactions
Captopril + Chlorthalidone
Severity: Moderate
Captopril and Chlorthalidone: moderate 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
The two drugs together give additive blood pressure lowering, and a marked drop may occur after the first captopril dose in volume-depleted patients. Renal function can also decline, especially with renal artery stenosis or dehydration.
What this interaction means in plain words
Captopril and Chlorthalidone can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Captopril belongs to Cardiovascular; Chlorthalidone belongs to Cardiovascular.
Why it happens
Diuretic-induced volume depletion activates the renin-angiotensin system, so ACE inhibition causes exaggerated hypotension and lowers glomerular filtration pressure.
What to do
Monitor blood pressure, creatinine and potassium after initiation and dose changes. Consider reducing or temporarily holding the diuretic before starting captopril.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Chlorthalidone
Other interactions of Captopril
- Aliskiren + Captopril Contraindicated
- Captopril + Sacubitril / valsartan Contraindicated
- Captopril + Sacubitril-valsartan Contraindicated
- Amifostine + Captopril Major
- Amiloride + Captopril Major
- Amlodipine-hydrochlorothiazide-valsartan + Captopril Major
Frequently asked questions
Can I take Captopril with Chlorthalidone?
MediHelp rates the interaction as moderate. Captopril and Chlorthalidone can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. The two drugs together give additive blood pressure lowering, and a marked drop may occur after the first captopril dose in volume-depleted patients. Renal function can also decline, especially with renal artery stenosis or dehydration.
How serious is the interaction between Captopril and Chlorthalidone?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor blood pressure, creatinine and potassium after initiation and dose changes. Consider reducing or temporarily holding the diuretic before starting captopril.
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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