Drug interactions
Candesartan-hydrochlorothiazide + Trimethoprim
Severity: Major
Candesartan-hydrochlorothiazide and Trimethoprim: 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
Trimethoprim reduces renal potassium excretion, and candesartan also tends to raise serum potassium. Together they can cause clinically significant hyperkalemia, especially in older patients, those with renal impairment, or with high trimethoprim doses. The thiazide component may partly offset the effect but does not remove the risk.
What this interaction means in plain words
Candesartan-hydrochlorothiazide and Trimethoprim 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.
Candesartan-hydrochlorothiazide belongs to Cardiovascular; Trimethoprim belongs to Anti Bacterial.
Why it happens
Trimethoprim blocks epithelial sodium channels in the distal nephron, which impairs potassium excretion and adds to the potassium-retaining effect of angiotensin receptor blockade.
What to do
Check serum potassium and creatinine within several days of starting trimethoprim and repeat periodically. Choose an alternative antibiotic in patients with renal impairment or other hyperkalemia risks.
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 Candesartan-hydrochlorothiazide
- Aliskiren + Candesartan-hydrochlorothiazide Contraindicated
- Candesartan-hydrochlorothiazide + Dofetilide Contraindicated
- Candesartan-hydrochlorothiazide + Sparsentan Contraindicated
- Acemetacin + Candesartan-hydrochlorothiazide Major
- Amifostine + Candesartan-hydrochlorothiazide Major
- Amiloride + Candesartan-hydrochlorothiazide Major
Other interactions of Trimethoprim
Frequently asked questions
Can I take Candesartan-hydrochlorothiazide with Trimethoprim?
MediHelp rates the interaction as major. Candesartan-hydrochlorothiazide and Trimethoprim 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. Trimethoprim reduces renal potassium excretion, and candesartan also tends to raise serum potassium. Together they can cause clinically significant hyperkalemia, especially in older patients, those with renal impairment, or with high trimethoprim doses. The thiazide component may partly offset the effect but does not remove the risk.
How serious is the interaction between Candesartan-hydrochlorothiazide and Trimethoprim?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check serum potassium and creatinine within several days of starting trimethoprim and repeat periodically. Choose an alternative antibiotic in patients with renal impairment or other hyperkalemia risks.
What other medicines interact with Candesartan-hydrochlorothiazide?
MediHelp also lists interactions of Candesartan-hydrochlorothiazide with, for example, Aliskiren, Dofetilide, Sparsentan. The full list is on the Candesartan-hydrochlorothiazide page.
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