Drug interactions
Levodopa + Thioridazine
Severity: Major
Levodopa and Thioridazine: 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
Thioridazine blocks dopamine D2 receptors and counteracts the antiparkinsonian effect of levodopa, potentially worsening motor symptoms. Phenothiazines can also worsen parkinsonism on their own.
What this interaction means in plain words
Levodopa and Thioridazine 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.
Levodopa belongs to Central Nervous System; Thioridazine belongs to Central Nervous System.
Why it happens
Pharmacodynamic antagonism at central dopamine D2 receptors.
What to do
Avoid thioridazine in Parkinson disease; if an antipsychotic is needed, use quetiapine or clozapine. Monitor motor function if exposure is unavoidable.
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 Thioridazine
- Abiraterone + Thioridazine Contraindicated
- Adagrasib + Thioridazine Contraindicated
- Amiodarone + Thioridazine Contraindicated
- Amisulpride + Thioridazine Contraindicated
- Amitriptyline + Thioridazine Contraindicated
- Amoxapine + Thioridazine Contraindicated
Other interactions of Levodopa
- Isocarboxazid + Levodopa Contraindicated
- Levodopa + Phenelzine Contraindicated
- Levodopa + Phenelzine (nonselective MAOI) Contraindicated
- Levodopa + Procarbazine Contraindicated
- Levodopa + Tranylcypromine Contraindicated
- Amisulpride + Levodopa Major
Frequently asked questions
Can I take Levodopa with Thioridazine?
MediHelp rates the interaction as major. Levodopa and Thioridazine 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. Thioridazine blocks dopamine D2 receptors and counteracts the antiparkinsonian effect of levodopa, potentially worsening motor symptoms. Phenothiazines can also worsen parkinsonism on their own.
How serious is the interaction between Levodopa and Thioridazine?
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 thioridazine in Parkinson disease; if an antipsychotic is needed, use quetiapine or clozapine. Monitor motor function if exposure is unavoidable.
What other medicines interact with Thioridazine?
MediHelp also lists interactions of Thioridazine with, for example, Abiraterone, Adagrasib, Amiodarone. The full list is on the Thioridazine page.
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