Drug interactions
Mirtazapine + Phenobarbital
Severity: Moderate
Mirtazapine 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
Phenobarbital adds CNS depression to mirtazapine's sedative effect. As a potent enzyme inducer it can also reduce mirtazapine concentrations and may weaken its antidepressant effect.
What this interaction means in plain words
Mirtazapine 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
Additive CNS depression and induction of CYP3A4 and other enzymes that metabolize mirtazapine.
What to do
Monitor sedation and depressive symptoms, and increase the mirtazapine dose if response is lost. Reassess the dose if phenobarbital is stopped.
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 Mirtazapine
- Isocarboxazid + Mirtazapine Contraindicated
- Mirtazapine + Phenelzine Contraindicated
- Mirtazapine + Pimozide Contraindicated
- Mirtazapine + Procarbazine Contraindicated
- Mirtazapine + Rasagiline Contraindicated
- Mirtazapine + Selegiline Contraindicated
Frequently asked questions
Can I take Mirtazapine with Phenobarbital?
MediHelp rates the interaction as moderate. Mirtazapine 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. Phenobarbital adds CNS depression to mirtazapine's sedative effect. As a potent enzyme inducer it can also reduce mirtazapine concentrations and may weaken its antidepressant effect.
How serious is the interaction between Mirtazapine 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 sedation and depressive symptoms, and increase the mirtazapine dose if response is lost. Reassess the dose if phenobarbital is stopped.
What other medicines interact with Mirtazapine?
MediHelp also lists interactions of Mirtazapine with, for example, Isocarboxazid, Phenelzine, Pimozide. The full list is on the Mirtazapine page.
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