Drug interactions
Diclofenac + Sulfamethoxazole
Severity: Minor
Diclofenac and Sulfamethoxazole: minor 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 inhibits CYP2C9 and may modestly raise diclofenac concentrations. This could increase the risk of NSAID adverse effects, including gastrointestinal and renal effects, particularly in at-risk patients.
What this interaction means in plain words
Diclofenac and Sulfamethoxazole have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Why it happens
Sulfamethoxazole inhibits CYP2C9, reducing diclofenac metabolism.
What to do
Monitor for GI and renal adverse effects, especially in older patients or those with kidney disease, and use the lowest effective diclofenac dose.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Diclofenac
- Diclofenac + Ketorolac Contraindicated
- Diclofenac + Ketorolac intranasal Contraindicated
- Aceclofenac + Diclofenac Major
- Acemetacin + Diclofenac Major
- Alteplase + Diclofenac Major
- Amiloride + Diclofenac Major
Frequently asked questions
Can I take Diclofenac with Sulfamethoxazole?
MediHelp rates the interaction as minor. Diclofenac and Sulfamethoxazole have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Sulfamethoxazole inhibits CYP2C9 and may modestly raise diclofenac concentrations. This could increase the risk of NSAID adverse effects, including gastrointestinal and renal effects, particularly in at-risk patients.
How serious is the interaction between Diclofenac and Sulfamethoxazole?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for GI and renal adverse effects, especially in older patients or those with kidney disease, and use the lowest effective diclofenac dose.
What other medicines interact with Diclofenac?
MediHelp also lists interactions of Diclofenac with, for example, Ketorolac, Ketorolac intranasal, Aceclofenac. The full list is on the Diclofenac page.
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