Drug interactions
Amiloride + Sulfamethoxazole
Severity: Moderate
Amiloride and Sulfamethoxazole: 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
Sulfamethoxazole is usually given with trimethoprim, which blocks epithelial sodium channels much like amiloride. Combined with amiloride, this can produce clinically significant hyperkalemia, particularly in older patients or those with renal impairment. Sulfamethoxazole alone has little effect on potassium.
What this interaction means in plain words
Amiloride and Sulfamethoxazole 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.
Why it happens
Additive potassium retention, mainly through trimethoprim in co-formulated products, together with amiloride's ENaC blockade in the distal nephron.
What to do
If a trimethoprim-containing product is used, check serum potassium and creatinine within the first days of therapy and periodically thereafter. Consider an alternative antibiotic in patients with renal impairment or other hyperkalemia risks.
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 Amiloride
- Amiloride + Eplerenone Contraindicated
- Amiloride + Spironolactone Contraindicated
- Amiloride + Triamterene Contraindicated
- Aceclofenac + Amiloride Major
- Acemetacin + Amiloride Major
- Amiloride + Amlodipine-benazepril Major
Frequently asked questions
Can I take Amiloride with Sulfamethoxazole?
MediHelp rates the interaction as moderate. Amiloride and Sulfamethoxazole 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. Sulfamethoxazole is usually given with trimethoprim, which blocks epithelial sodium channels much like amiloride. Combined with amiloride, this can produce clinically significant hyperkalemia, particularly in older patients or those with renal impairment. Sulfamethoxazole alone has little effect on potassium.
How serious is the interaction between Amiloride and Sulfamethoxazole?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: If a trimethoprim-containing product is used, check serum potassium and creatinine within the first days of therapy and periodically thereafter. Consider an alternative antibiotic in patients with renal impairment or other hyperkalemia risks.
What other medicines interact with Amiloride?
MediHelp also lists interactions of Amiloride with, for example, Eplerenone, Spironolactone, Triamterene. The full list is on the Amiloride page.
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