Drug interactions
Levodopa + Tolcapone
Severity: Moderate
Levodopa and Tolcapone: 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
Tolcapone blocks peripheral breakdown of levodopa, raising levodopa exposure and prolonging its effect. This improves motor fluctuations but increases dopaminergic adverse effects such as dyskinesia, nausea, hallucinations and orthostatic hypotension.
What this interaction means in plain words
Levodopa and Tolcapone 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.
Levodopa belongs to Central Nervous System; Tolcapone belongs to Central Nervous System.
Why it happens
COMT inhibition by tolcapone reduces conversion of levodopa to 3-O-methyldopa, increasing levodopa bioavailability and half-life.
What to do
Lower the levodopa dose when starting tolcapone, often by about 30% or more in patients with dyskinesia. Monitor for dyskinesia and hallucinations.
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 Tolcapone
- Isocarboxazid + Tolcapone Contraindicated
- Phenelzine + Tolcapone Contraindicated
- Tolcapone + Tranylcypromine Contraindicated
- Metoclopramide + Tolcapone Major
- Apomorphine + Tolcapone Moderate
- Asenapine + Tolcapone Moderate
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 Tolcapone?
MediHelp rates the interaction as moderate. Levodopa and Tolcapone 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. Tolcapone blocks peripheral breakdown of levodopa, raising levodopa exposure and prolonging its effect. This improves motor fluctuations but increases dopaminergic adverse effects such as dyskinesia, nausea, hallucinations and orthostatic hypotension.
How serious is the interaction between Levodopa and Tolcapone?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Lower the levodopa dose when starting tolcapone, often by about 30% or more in patients with dyskinesia. Monitor for dyskinesia and hallucinations.
What other medicines interact with Tolcapone?
MediHelp also lists interactions of Tolcapone with, for example, Isocarboxazid, Phenelzine, Tranylcypromine. The full list is on the Tolcapone page.
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