Drug interactions
Diclofenac + Efavirenz
Severity: Minor
Diclofenac and Efavirenz: 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
Efavirenz has variable effects on CYP2C9, and its influence on diclofenac exposure is uncertain and not well documented. Efavirenz is more commonly an inducer, so reduced diclofenac effect is as plausible as increased exposure.
What this interaction means in plain words
Diclofenac and Efavirenz have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Diclofenac belongs to Musculoskeletal; Efavirenz belongs to Anti Virals.
Why it happens
Possible modulation of CYP2C9 metabolism of diclofenac by efavirenz; direction and magnitude not firmly established.
What to do
No dose change is routinely needed. Monitor analgesic response and NSAID adverse effects.
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
Other interactions of Efavirenz
- Cobimetinib + Efavirenz Contraindicated
- Dienogest / estradiol valerate + Efavirenz Contraindicated
- Dihydroergotamine intranasal + Efavirenz Contraindicated
- Dihydroergotamine + Efavirenz Contraindicated
- Doravirine + Efavirenz Contraindicated
- Efavirenz + Elbasvir / grazoprevir Contraindicated
Frequently asked questions
Can I take Diclofenac with Efavirenz?
MediHelp rates the interaction as minor. Diclofenac and Efavirenz have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Efavirenz has variable effects on CYP2C9, and its influence on diclofenac exposure is uncertain and not well documented. Efavirenz is more commonly an inducer, so reduced diclofenac effect is as plausible as increased exposure.
How serious is the interaction between Diclofenac and Efavirenz?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No dose change is routinely needed. Monitor analgesic response and NSAID adverse effects.
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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