Drug interactions
Clozapine + Mirtazapine
Severity: Moderate
Clozapine and Mirtazapine: 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
Both drugs are sedating, and the combination can increase drowsiness, weight gain and metabolic effects. Both have been associated with QT prolongation, and mirtazapine may rarely add to clozapine hematologic or cardiac risks, so overall risk is increased.
What this interaction means in plain words
Clozapine and Mirtazapine 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.
Clozapine belongs to Central Nervous System; Mirtazapine belongs to Central Nervous System.
Why it happens
Additive CNS depression, antihistaminic effects and possible additive QT prolongation.
What to do
Monitor sedation, weight, glucose and lipids, and obtain an ECG if there are other QT risk factors. Keep electrolytes within normal range and continue routine clozapine blood monitoring.
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
Other interactions of Clozapine
- Clozapine + Deferiprone Contraindicated
- Clozapine + Irinotecan Contraindicated
- Clozapine + Pimozide Contraindicated
- Clozapine + Thioridazine Contraindicated
- Acalabrutinib + Clozapine Major
- Adagrasib + Clozapine Major
Frequently asked questions
Can I take Clozapine with Mirtazapine?
MediHelp rates the interaction as moderate. Clozapine and Mirtazapine 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. Both drugs are sedating, and the combination can increase drowsiness, weight gain and metabolic effects. Both have been associated with QT prolongation, and mirtazapine may rarely add to clozapine hematologic or cardiac risks, so overall risk is increased.
How serious is the interaction between Clozapine and Mirtazapine?
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, weight, glucose and lipids, and obtain an ECG if there are other QT risk factors. Keep electrolytes within normal range and continue routine clozapine blood monitoring.
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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