Drug interactions
Fenfluramine + Nortriptyline
Severity: Major
Fenfluramine and Nortriptyline: major 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
Fenfluramine increases serotonin release and tricyclic antidepressants add serotonergic and noradrenergic activity, so serotonin syndrome is possible. Nortriptyline is a weaker serotonergic agent than SSRIs, but caution is still needed. Fenfluramine labeling also advises caution with other serotonergic drugs.
What this interaction means in plain words
Fenfluramine and Nortriptyline 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.
Fenfluramine belongs to Central Nervous System; Nortriptyline belongs to Central Nervous System.
Why it happens
Additive serotonergic effects: fenfluramine releases serotonin and nortriptyline inhibits reuptake of serotonin and norepinephrine.
What to do
Avoid the combination if possible. If both are required, start at low doses and monitor for agitation, tremor, hyperthermia, clonus and autonomic instability.
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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Other interactions of Nortriptyline
- Disopyramide + Nortriptyline Contraindicated
- Dofetilide + Nortriptyline Contraindicated
- Dronedarone + Nortriptyline Contraindicated
- Ibutilide + Nortriptyline Contraindicated
- Isocarboxazid + Nortriptyline Contraindicated
- Methylene blue + Nortriptyline Contraindicated
Other interactions of Fenfluramine
- Fenfluramine + Isocarboxazid Contraindicated
- Fenfluramine + Linezolid Contraindicated
- Fenfluramine + Phenelzine Contraindicated
- Fenfluramine + Selegiline Contraindicated
- Fenfluramine + Tranylcypromine Contraindicated
- Almotriptan + Fenfluramine Major
Frequently asked questions
Can I take Fenfluramine with Nortriptyline?
MediHelp rates the interaction as major. Fenfluramine and Nortriptyline 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. Fenfluramine increases serotonin release and tricyclic antidepressants add serotonergic and noradrenergic activity, so serotonin syndrome is possible. Nortriptyline is a weaker serotonergic agent than SSRIs, but caution is still needed. Fenfluramine labeling also advises caution with other serotonergic drugs.
How serious is the interaction between Fenfluramine and Nortriptyline?
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 if possible. If both are required, start at low doses and monitor for agitation, tremor, hyperthermia, clonus and autonomic instability.
What other medicines interact with Nortriptyline?
MediHelp also lists interactions of Nortriptyline with, for example, Disopyramide, Dofetilide, Dronedarone. The full list is on the Nortriptyline page.
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