Drug interactions
Buprenorphine + Phenytoin
Severity: Moderate
Buprenorphine and Phenytoin: 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
Phenytoin induces CYP3A4 and can lower buprenorphine concentrations, which may cause withdrawal symptoms or loss of analgesia. Both drugs can also cause sedation, so CNS effects may be additive.
What this interaction means in plain words
Buprenorphine and Phenytoin 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.
Buprenorphine belongs to Musculoskeletal; Phenytoin belongs to Central Nervous System.
Why it happens
CYP3A4 induction by phenytoin increases buprenorphine metabolism.
What to do
Monitor for withdrawal symptoms and inadequate pain control, and increase the buprenorphine dose if needed. Reassess the dose if phenytoin is stopped, since induction reverses over weeks.
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 Buprenorphine
- Alvimopan + Buprenorphine Contraindicated
- Buprenorphine + Calcium / magnesium / potassium / sodium oxybates Contraindicated
- Buprenorphine + Olanzapine / samidorphan Contraindicated
- Buprenorphine + Phenelzine Contraindicated
- Buprenorphine + Pimozide Contraindicated
- Buprenorphine + Thioridazine Contraindicated
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 Buprenorphine with Phenytoin?
MediHelp rates the interaction as moderate. Buprenorphine and Phenytoin 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. Phenytoin induces CYP3A4 and can lower buprenorphine concentrations, which may cause withdrawal symptoms or loss of analgesia. Both drugs can also cause sedation, so CNS effects may be additive.
How serious is the interaction between Buprenorphine and Phenytoin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for withdrawal symptoms and inadequate pain control, and increase the buprenorphine dose if needed. Reassess the dose if phenytoin is stopped, since induction reverses over weeks.
What other medicines interact with Buprenorphine?
MediHelp also lists interactions of Buprenorphine with, for example, Alvimopan, Calcium / magnesium / potassium / sodium oxybates, Olanzapine / samidorphan. The full list is on the Buprenorphine page.
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