Drug interactions
Ramipril + Trimethoprim
Severity: Major
Ramipril 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
Both drugs raise serum potassium, and the combination can cause clinically significant hyperkalemia. The risk is greatest with high-dose trimethoprim, renal impairment, diabetes, advanced age, or other potassium-raising drugs.
What this interaction means in plain words
Ramipril 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.
Ramipril belongs to Cardiovascular; Trimethoprim belongs to Anti Bacterial.
Why it happens
Trimethoprim blocks epithelial sodium channels in the distal nephron, reducing potassium excretion, while ACE inhibition reduces aldosterone-mediated potassium excretion.
What to do
Avoid the combination in patients with renal impairment or other risk factors, or choose an alternative antibiotic. If used, check serum potassium and creatinine within a few days of starting.
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 Ramipril
- Aliskiren + Ramipril Contraindicated
- Protein a column + Ramipril Contraindicated
- Ramipril + Sacubitril / valsartan Contraindicated
- Ramipril + Sacubitril-valsartan Contraindicated
- Amifostine + Ramipril Major
- Amiloride + Ramipril Major
Other interactions of Trimethoprim
Frequently asked questions
Can I take Ramipril with Trimethoprim?
MediHelp rates the interaction as major. Ramipril 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. Both drugs raise serum potassium, and the combination can cause clinically significant hyperkalemia. The risk is greatest with high-dose trimethoprim, renal impairment, diabetes, advanced age, or other potassium-raising drugs.
How serious is the interaction between Ramipril 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: Avoid the combination in patients with renal impairment or other risk factors, or choose an alternative antibiotic. If used, check serum potassium and creatinine within a few days of starting.
What other medicines interact with Ramipril?
MediHelp also lists interactions of Ramipril with, for example, Aliskiren, Protein a column, Sacubitril / valsartan. The full list is on the Ramipril page.
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