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Drug interactions

Phenobarbital + Tofacitinib

Severity: Moderate

Phenobarbital and Tofacitinib: 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

Phenobarbital is a CYP3A4 inducer that may lower tofacitinib exposure and reduce its effect. The effect is likely relevant with chronic use.

What this interaction means in plain words

Phenobarbital and Tofacitinib 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.

Evidence level: Moderate

Why it happens

Induction of CYP3A4 increases tofacitinib clearance.

What to do

Monitor for loss of response to tofacitinib; consider an alternative therapy if disease control worsens.

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?

Bring a full list of your medicines, including over-the-counter products, supplements and herbal remedies, to every pharmacy visit.

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Frequently asked questions

Can I take Phenobarbital with Tofacitinib?

MediHelp rates the interaction as moderate. Phenobarbital and Tofacitinib 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. Phenobarbital is a CYP3A4 inducer that may lower tofacitinib exposure and reduce its effect. The effect is likely relevant with chronic use.

How serious is the interaction between Phenobarbital and Tofacitinib?

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 loss of response to tofacitinib; consider an alternative therapy if disease control worsens.

What other medicines interact with Tofacitinib?

MediHelp also lists interactions of Tofacitinib with, for example, Baricitinib, Cladribine, Upadacitinib. The full list is on the Tofacitinib page.

Full monographs, dosing and an interaction checker in the MediHelp app

Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.

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