Drug interactions
Amifampridine + Promethazine
Severity: Moderate
Amifampridine and Promethazine: 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
Amifampridine carries a dose-related risk of seizures, and promethazine can lower the seizure threshold. Using both may increase seizure risk.
What this interaction means in plain words
Amifampridine and Promethazine 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.
Amifampridine belongs to Central Nervous System; Promethazine belongs to Respiratory.
Why it happens
Additive lowering of seizure threshold by phenothiazine antihistamine activity and amifampridine potassium channel blockade.
What to do
Avoid promethazine where alternatives exist; otherwise use the lowest dose and monitor for seizure activity.
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 Promethazine
- Ibutilide + Promethazine Contraindicated
- Pimozide + Promethazine Contraindicated
- Promethazine + Thioridazine Contraindicated
- Alfentanil + Promethazine Major
- Amiodarone + Promethazine Major
- Amisulpride + Promethazine Major
Other interactions of Amifampridine
- Amifampridine + Bupropion-naltrexone Major
- Amantadine + Amifampridine Moderate
- Amifampridine + Amitriptyline Moderate
- Amifampridine + Baclofen Moderate
- Amifampridine + Bethanechol Moderate
- Amifampridine + Bromocriptine Moderate
Frequently asked questions
Can I take Amifampridine with Promethazine?
MediHelp rates the interaction as moderate. Amifampridine and Promethazine 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. Amifampridine carries a dose-related risk of seizures, and promethazine can lower the seizure threshold. Using both may increase seizure risk.
How serious is the interaction between Amifampridine and Promethazine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid promethazine where alternatives exist; otherwise use the lowest dose and monitor for seizure activity.
What other medicines interact with Promethazine?
MediHelp also lists interactions of Promethazine with, for example, Ibutilide, Pimozide, Thioridazine. The full list is on the Promethazine page.
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