Drug interactions
Phenobarbital + Trazodone
Severity: Moderate
Phenobarbital and Trazodone: 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 and trazodone both cause sedation, increasing the risk of drowsiness, impaired coordination and respiratory depression. Phenobarbital also induces CYP3A4 and can lower trazodone concentrations over time.
What this interaction means in plain words
Phenobarbital and Trazodone 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
Additive CNS depression plus CYP3A4 induction by phenobarbital increasing trazodone metabolism.
What to do
Monitor sedation and therapeutic response, and adjust the trazodone dose if efficacy falls. Advise patients to avoid alcohol and driving until the response is known.
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 Trazodone
- Arsenic trioxide + Trazodone Contraindicated
- Ibutilide + Trazodone Contraindicated
- Isocarboxazid + Trazodone Contraindicated
- Levoketoconazole + Trazodone Contraindicated
- Methylene blue + Trazodone Contraindicated
- Phenelzine + Trazodone Contraindicated
Frequently asked questions
Can I take Phenobarbital with Trazodone?
MediHelp rates the interaction as moderate. Phenobarbital and Trazodone 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 and trazodone both cause sedation, increasing the risk of drowsiness, impaired coordination and respiratory depression. Phenobarbital also induces CYP3A4 and can lower trazodone concentrations over time.
How serious is the interaction between Phenobarbital and Trazodone?
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 sedation and therapeutic response, and adjust the trazodone dose if efficacy falls. Advise patients to avoid alcohol and driving until the response is known.
What other medicines interact with Trazodone?
MediHelp also lists interactions of Trazodone with, for example, Arsenic trioxide, Ibutilide, Isocarboxazid. The full list is on the Trazodone page.
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