Drug interactions
Carbidopa-levodopa + Haloperidol
Severity: Major
Carbidopa-levodopa and Haloperidol: major interaction.
Last updated Sources: US FDA label
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
Haloperidol strongly blocks D2 receptors and can markedly worsen parkinsonism while blunting levodopa efficacy.
What this interaction means in plain words
Carbidopa-levodopa and Haloperidol 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-levodopa belongs to Central Nervous System; Haloperidol belongs to Central Nervous System.
Why it happens
Pharmacodynamic antagonism: D2 receptor blockade by haloperidol opposes levodopa.
What to do
Avoid in Parkinson's disease and use quetiapine or clozapine if an antipsychotic is required. Monitor motor function if it cannot be avoided.
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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References
Other interactions of Carbidopa-levodopa
- Carbidopa-levodopa + Isocarboxazid Contraindicated
- Carbidopa-levodopa + Phenelzine Contraindicated
- Carbidopa-levodopa + Selegiline transdermal Contraindicated
- Carbidopa-levodopa + Tranylcypromine Contraindicated
- Amisulpride + Carbidopa-levodopa Major
- Asenapine + Carbidopa-levodopa Major
Other interactions of Haloperidol
- Dofetilide + Haloperidol Contraindicated
- Dronedarone + Haloperidol Contraindicated
- Haloperidol + Ibutilide Contraindicated
- Haloperidol + Levoketoconazole Contraindicated
- Haloperidol + Panobinostat Contraindicated
- Haloperidol + Pimozide Contraindicated
Frequently asked questions
Can I take Carbidopa-levodopa with Haloperidol?
MediHelp rates the interaction as major. Carbidopa-levodopa and Haloperidol 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. Haloperidol strongly blocks D2 receptors and can markedly worsen parkinsonism while blunting levodopa efficacy.
How serious is the interaction between Carbidopa-levodopa and Haloperidol?
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 in Parkinson's disease and use quetiapine or clozapine if an antipsychotic is required. Monitor motor function if it cannot be avoided.
What other medicines interact with Carbidopa-levodopa?
MediHelp also lists interactions of Carbidopa-levodopa with, for example, Isocarboxazid, Phenelzine, Selegiline transdermal. The full list is on the Carbidopa-levodopa page.
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