Drug interactions
Fenfluramine + Lithium
Severity: Moderate
Fenfluramine and Lithium: 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
Fenfluramine releases serotonin and lithium can enhance serotonergic function. Together they may raise the risk of serotonin syndrome. Fenfluramine labeling warns about combining it with other serotonergic drugs.
What this interaction means in plain words
Fenfluramine and Lithium 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.
Fenfluramine belongs to Central Nervous System; Lithium belongs to Central Nervous System.
Why it happens
Additive serotonergic effects from serotonin release (fenfluramine) and enhanced serotonergic transmission (lithium).
What to do
Monitor for mental status change, neuromuscular hyperactivity and autonomic instability, particularly when starting or raising doses. Discontinue the serotonergic agent if serotonin syndrome develops.
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 Lithium
- Lithium + Thioridazine Contraindicated
- Lithium + Vandetanib Contraindicated
- Aceclofenac + Lithium Major
- Acemetacin + Lithium Major
- Amisulpride + Lithium Major
- Amlodipine-benazepril + Lithium Major
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 Lithium?
MediHelp rates the interaction as moderate. Fenfluramine and Lithium 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. Fenfluramine releases serotonin and lithium can enhance serotonergic function. Together they may raise the risk of serotonin syndrome. Fenfluramine labeling warns about combining it with other serotonergic drugs.
How serious is the interaction between Fenfluramine and Lithium?
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 for mental status change, neuromuscular hyperactivity and autonomic instability, particularly when starting or raising doses. Discontinue the serotonergic agent if serotonin syndrome develops.
What other medicines interact with Lithium?
MediHelp also lists interactions of Lithium with, for example, Thioridazine, Vandetanib, Aceclofenac. The full list is on the Lithium page.
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