Drug interactions
Telmisartan-amlodipine + Trimethoprim
Severity: Major
Telmisartan-amlodipine 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 potassium excretion in the distal nephron, and telmisartan reduces aldosterone effect. Together they can cause clinically significant hyperkalemia, particularly in older patients or those with renal impairment.
What this interaction means in plain words
Telmisartan-amlodipine 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.
Telmisartan-amlodipine belongs to Cardiovascular; Trimethoprim belongs to Anti Bacterial.
Why it happens
Trimethoprim inhibits epithelial sodium channels in the collecting duct, which, combined with ARB-induced aldosterone suppression, impairs potassium excretion.
What to do
Check serum potassium and creatinine within a few days of starting trimethoprim and periodically thereafter. 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 Telmisartan-amlodipine
- Aliskiren + Telmisartan-amlodipine Contraindicated
- Sparsentan + Telmisartan-amlodipine Contraindicated
- Amifostine + Telmisartan-amlodipine Major
- Amiloride + Telmisartan-amlodipine Major
- Benazepril + Telmisartan-amlodipine Major
- Candesartan + Telmisartan-amlodipine Major
Other interactions of Trimethoprim
Frequently asked questions
Can I take Telmisartan-amlodipine with Trimethoprim?
MediHelp rates the interaction as major. Telmisartan-amlodipine 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 potassium excretion in the distal nephron, and telmisartan reduces aldosterone effect. Together they can cause clinically significant hyperkalemia, particularly in older patients or those with renal impairment.
How serious is the interaction between Telmisartan-amlodipine 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 a few days of starting trimethoprim and periodically thereafter. Choose an alternative antibiotic in patients with renal impairment or other hyperkalemia risks.
What other medicines interact with Telmisartan-amlodipine?
MediHelp also lists interactions of Telmisartan-amlodipine with, for example, Aliskiren, Sparsentan, Amifostine. The full list is on the Telmisartan-amlodipine page.
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