Drug interactions
Carbidopa-entacapone-levodopa + Thioridazine
Severity: Major
Carbidopa-entacapone-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 receptors and opposes levodopa, which can worsen parkinsonian symptoms. It also carries a substantial risk of QT prolongation and arrhythmia.
What this interaction means in plain words
Carbidopa-entacapone-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.
Carbidopa-entacapone-levodopa belongs to Central Nervous System; Thioridazine belongs to Central Nervous System.
Why it happens
Pharmacodynamic antagonism via D2 receptor blockade.
What to do
Avoid thioridazine in patients on levodopa and choose quetiapine or clozapine. If unavoidable, monitor motor function and ECG.
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 Carbidopa-entacapone-levodopa
- Carbidopa-entacapone-levodopa + Isocarboxazid Contraindicated
- Carbidopa-entacapone-levodopa + Phenelzine Contraindicated
- Carbidopa-entacapone-levodopa + Selegiline transdermal Contraindicated
- Carbidopa-entacapone-levodopa + Tranylcypromine Contraindicated
- Amisulpride + Carbidopa-entacapone-levodopa Major
- Asenapine transdermal + Carbidopa-entacapone-levodopa Major
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 Carbidopa-entacapone-levodopa with Thioridazine?
MediHelp rates the interaction as major. Carbidopa-entacapone-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 receptors and opposes levodopa, which can worsen parkinsonian symptoms. It also carries a substantial risk of QT prolongation and arrhythmia.
How serious is the interaction between Carbidopa-entacapone-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 patients on levodopa and choose quetiapine or clozapine. If unavoidable, monitor motor function and ECG.
What other medicines interact with Carbidopa-entacapone-levodopa?
MediHelp also lists interactions of Carbidopa-entacapone-levodopa with, for example, Isocarboxazid, Phenelzine, Selegiline transdermal. The full list is on the Carbidopa-entacapone-levodopa page.
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