Drug interactions
Dexfenfluramine + Mirtazapine
Severity: Major
Dexfenfluramine and Mirtazapine: major interaction.
Last updated Sources: US FDA label
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
Dexfenfluramine releases serotonin and blocks its reuptake, so combining it with a serotonergic antidepressant may increase the risk of serotonin syndrome. The drug is withdrawn in most markets, so this is mainly of historical relevance.
What this interaction means in plain words
Dexfenfluramine and Mirtazapine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Additive serotonergic activity from serotonin release and reuptake inhibition combined with mirtazapine's serotonergic effects.
What to do
Avoid the combination where possible, and watch for agitation, tremor, hyperthermia and clonus if both are given. Stop the serotonergic agents if serotonin syndrome is suspected.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
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 Dexfenfluramine with Mirtazapine?
MediHelp rates the interaction as major. Dexfenfluramine and Mirtazapine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Dexfenfluramine releases serotonin and blocks its reuptake, so combining it with a serotonergic antidepressant may increase the risk of serotonin syndrome. The drug is withdrawn in most markets, so this is mainly of historical relevance.
How serious is the interaction between Dexfenfluramine and Mirtazapine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination where possible, and watch for agitation, tremor, hyperthermia and clonus if both are given. Stop the serotonergic agents if serotonin syndrome is suspected.
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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