Drug interactions
Primidone + Trazodone
Severity: Moderate
Primidone 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
Primidone is metabolised to phenobarbital, so it adds sedation to trazodone and induces CYP3A4. This may lower trazodone concentrations and reduce its benefit while increasing drowsiness.
What this interaction means in plain words
Primidone 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.
Primidone belongs to Central Nervous System; Trazodone belongs to Central Nervous System.
Why it happens
Additive CNS depression plus CYP3A4 induction by primidone and its phenobarbital metabolite.
What to do
Monitor sedation and antidepressant response, and increase the trazodone dose if needed. Counsel 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
Other interactions of Primidone
- Lorlatinib + Primidone Contraindicated
- Lurasidone + Primidone Contraindicated
- Primidone + Ranolazine Contraindicated
- Primidone + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
- Primidone + Voriconazole Contraindicated
- Abiraterone + Primidone Major
Frequently asked questions
Can I take Primidone with Trazodone?
MediHelp rates the interaction as moderate. Primidone 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. Primidone is metabolised to phenobarbital, so it adds sedation to trazodone and induces CYP3A4. This may lower trazodone concentrations and reduce its benefit while increasing drowsiness.
How serious is the interaction between Primidone 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 antidepressant response, and increase the trazodone dose if needed. Counsel 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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