Co Trimoxazole and Spironolactone: Drug Interaction Guide
Quick answer: This is a major interaction — avoid combining Co Trimoxazole and Spironolactone unless specifically directed by your doctor.
How Co Trimoxazole interacts with Spironolactone
Trimethoprim inhibits epithelial sodium channels in the distal nephron, producing an amiloride-like potassium-retaining effect that adds to aldosterone antagonism by spironolactone.
What you should do
Avoid this combination, particularly in older adults or patients with renal impairment. Use another antibiotic and monitor potassium if exposure occurs.
Key facts
Severity
Major — avoid combination
Mechanism
Trimethoprim inhibits epithelial sodium channels in the distal nephron, producing an amiloride-like potassium-retaining ...
Action
Avoid this combination, particularly in older adults or patients with renal impairment. Use another antibiotic and monit...
Frequently asked questions
Can I take Co Trimoxazole and Spironolactone together?
No — this combination should generally be avoided. Avoid this combination, particularly in older adults or patients with renal impairment. Use another antibiotic and monitor potassium if exposure occurs.
What is the severity of this interaction?
The interaction between Co Trimoxazole and Spironolactone is classified as Major — avoid combination. Trimethoprim inhibits epithelial sodium channels in the distal nephron, producing an amiloride-like potassium-retaining effect that adds to aldosterone antagonism by spironolactone.
What should I do if I'm prescribed both?
Avoid this combination, particularly in older adults or patients with renal impairment. Use another antibiotic and monitor potassium if exposure occurs. Always consult your prescribing clinician — do not stop or change medications without medical guidance.
Last reviewed: by iMedic Medical Editorial Team. Our editorial process.