Drug interactions
Amantadine + Thioridazine
Severity: Moderate
Amantadine and Thioridazine: 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
Thioridazine blocks dopamine receptors and can worsen parkinsonian symptoms, opposing the dopaminergic benefit of amantadine. Thioridazine also carries a significant QT-prolongation risk independent of amantadine, and amantadine has been linked to QT prolongation in rare cases.
What this interaction means in plain words
Amantadine and Thioridazine 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.
Amantadine belongs to Anti Virals; Thioridazine belongs to Central Nervous System.
Why it happens
Pharmacodynamic antagonism of dopaminergic effect by D2 blockade, with possible additive QT effects.
What to do
Avoid thioridazine in patients treated for parkinsonism where possible and choose an alternative antipsychotic with low D2 affinity. If both are used, monitor motor symptoms and the ECG.
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 Amantadine
- Amantadine + Ethanol Major
- Amantadine + Memantine-donepezil Major
- Amantadine + Metoclopramide Major
- Amantadine + Metoclopramide intranasal Major
- Amantadine + Amifampridine Moderate
- Amantadine + Amisulpride Moderate
Other interactions of Thioridazine
- Abiraterone + Thioridazine Contraindicated
- Adagrasib + Thioridazine Contraindicated
- Amiodarone + Thioridazine Contraindicated
- Amisulpride + Thioridazine Contraindicated
- Amitriptyline + Thioridazine Contraindicated
- Amoxapine + Thioridazine Contraindicated
Frequently asked questions
Can I take Amantadine with Thioridazine?
MediHelp rates the interaction as moderate. Amantadine and Thioridazine 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. Thioridazine blocks dopamine receptors and can worsen parkinsonian symptoms, opposing the dopaminergic benefit of amantadine. Thioridazine also carries a significant QT-prolongation risk independent of amantadine, and amantadine has been linked to QT prolongation in rare cases.
How serious is the interaction between Amantadine and Thioridazine?
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 thioridazine in patients treated for parkinsonism where possible and choose an alternative antipsychotic with low D2 affinity. If both are used, monitor motor symptoms and the ECG.
What other medicines interact with Amantadine?
MediHelp also lists interactions of Amantadine with, for example, Ethanol, Memantine-donepezil, Metoclopramide. The full list is on the Amantadine page.
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