Drug interactions
Candesartan + Trimethoprim
Severity: Major
Candesartan 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 blocks epithelial sodium channels in the distal nephron and reduces potassium excretion, while candesartan lowers aldosterone-mediated potassium excretion. Together they can cause clinically significant hyperkalemia, particularly in older patients, those with renal impairment, or those on high trimethoprim doses.
What this interaction means in plain words
Candesartan 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 belongs to Cardiovascular; Trimethoprim belongs to Anti Bacterial.
Why it happens
Additive reduction of renal potassium excretion through ENaC blockade (trimethoprim) and angiotensin II receptor blockade (candesartan).
What to do
Check serum potassium and creatinine within several days of starting trimethoprim, and again if therapy continues. Prefer an alternative antibiotic in high-risk patients.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Candesartan and Trimethoprim, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Candesartan
- Aliskiren + Candesartan Contraindicated
- Candesartan + Sparsentan Contraindicated
- Amifostine + Candesartan Major
- Amiloride + Candesartan Major
- Amlodipine-benazepril + Candesartan Major
- Amlodipine-hydrochlorothiazide-valsartan + Candesartan Major
Other interactions of Trimethoprim
Frequently asked questions
Can I take Candesartan with Trimethoprim?
MediHelp rates the interaction as major. Candesartan 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 blocks epithelial sodium channels in the distal nephron and reduces potassium excretion, while candesartan lowers aldosterone-mediated potassium excretion. Together they can cause clinically significant hyperkalemia, particularly in older patients, those with renal impairment, or those on high trimethoprim doses.
How serious is the interaction between Candesartan 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 again if therapy continues. Prefer an alternative antibiotic in high-risk patients.
What other medicines interact with Candesartan?
MediHelp also lists interactions of Candesartan with, for example, Aliskiren, Sparsentan, Amifostine. The full list is on the Candesartan page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
