Drug interactions
Apalutamide + Phenobarbital
Severity: Moderate
Apalutamide and Phenobarbital: 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
Apalutamide may reduce phenobarbital levels, risking loss of seizure control. Phenobarbital itself is a strong CYP3A4 inducer and may lower apalutamide exposure too.
What this interaction means in plain words
Apalutamide and Phenobarbital 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.
Why it happens
Apalutamide induces CYP2C19, which contributes to phenobarbital metabolism; phenobarbital reciprocally induces CYP3A4.
What to do
Monitor phenobarbital serum concentrations and seizure control. Avoid pairing with strong inducers of apalutamide metabolism where possible.
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 Apalutamide
- Apalutamide + Cabotegravir Contraindicated
- Apalutamide + Cobicistat Contraindicated
- Apalutamide + Doravirine Contraindicated
- Apalutamide + Elbasvir / grazoprevir Contraindicated
- Apalutamide + Ensitrelvir Contraindicated
- Apalutamide + Fostemsavir Contraindicated
Frequently asked questions
Can I take Apalutamide with Phenobarbital?
MediHelp rates the interaction as moderate. Apalutamide and Phenobarbital 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. Apalutamide may reduce phenobarbital levels, risking loss of seizure control. Phenobarbital itself is a strong CYP3A4 inducer and may lower apalutamide exposure too.
How serious is the interaction between Apalutamide and Phenobarbital?
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 phenobarbital serum concentrations and seizure control. Avoid pairing with strong inducers of apalutamide metabolism where possible.
What other medicines interact with Apalutamide?
MediHelp also lists interactions of Apalutamide with, for example, Cabotegravir, Cobicistat, Doravirine. The full list is on the Apalutamide page.
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