Drug interactions
Parecoxib + Phenytoin
Severity: Minor
Parecoxib and Phenytoin: 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
Parecoxib is converted to valdecoxib, which is metabolized by CYP3A4 and CYP2C9. Phenytoin induces these enzymes and may lower valdecoxib exposure, possibly reducing analgesic effect.
What this interaction means in plain words
Parecoxib and Phenytoin 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
Phenytoin induces CYP3A4 and CYP2C9, increasing valdecoxib clearance.
What to do
Monitor analgesic response and consider dose adjustment if pain control is inadequate.
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 Phenytoin
- Artemether / lumefantrine + Phenytoin Contraindicated
- Bictegravir + Phenytoin Contraindicated
- Cabotegravir + Phenytoin Contraindicated
- Doravirine + Phenytoin Contraindicated
- Elbasvir / grazoprevir + Phenytoin Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Phenytoin Contraindicated
Frequently asked questions
Can I take Parecoxib with Phenytoin?
MediHelp rates the interaction as minor. Parecoxib and Phenytoin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Parecoxib is converted to valdecoxib, which is metabolized by CYP3A4 and CYP2C9. Phenytoin induces these enzymes and may lower valdecoxib exposure, possibly reducing analgesic effect.
How serious is the interaction between Parecoxib and Phenytoin?
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 analgesic response and consider dose adjustment if pain control is inadequate.
What other medicines interact with Phenytoin?
MediHelp also lists interactions of Phenytoin with, for example, Artemether / lumefantrine, Bictegravir, Cabotegravir. The full list is on the Phenytoin page.
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