Drug interactions
Carbidopa-entacapone-levodopa + Methyldopa
Severity: Moderate
Carbidopa-entacapone-levodopa and Methyldopa: 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
Levodopa and methyldopa can both lower blood pressure, and the combination may cause additive hypotension. Methyldopa has also been reported to alter the response to levodopa, with possible worsening of parkinsonism or CNS effects such as confusion. Entacapone may modestly raise methyldopa exposure because both involve COMT-related handling.
What this interaction means in plain words
Carbidopa-entacapone-levodopa and Methyldopa 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.
Carbidopa-entacapone-levodopa belongs to Central Nervous System; Methyldopa belongs to Cardiovascular.
Why it happens
Additive hypotensive effects, with methyldopa acting as a central dopamine-synthesis inhibitor that interferes with levodopa, and COMT inhibition by entacapone possibly reducing methyldopa metabolism.
What to do
Monitor blood pressure, including orthostatic readings, and watch for changes in parkinsonian control or mental status. Reduce the antihypertensive dose if symptomatic hypotension occurs, or choose a different antihypertensive.
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 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 Methyldopa
- Methyldopa + Tranylcypromine Contraindicated
- Iobenguane i + Methyldopa Major
- Lofexidine + Methyldopa Major
- Methyldopa + Pexidartinib Major
- Methyldopa + Pretomanid Major
- Methyldopa + Thioridazine Major
Frequently asked questions
Can I take Carbidopa-entacapone-levodopa with Methyldopa?
MediHelp rates the interaction as moderate. Carbidopa-entacapone-levodopa and Methyldopa 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 and methyldopa can both lower blood pressure, and the combination may cause additive hypotension. Methyldopa has also been reported to alter the response to levodopa, with possible worsening of parkinsonism or CNS effects such as confusion. Entacapone may modestly raise methyldopa exposure because both involve COMT-related handling.
How serious is the interaction between Carbidopa-entacapone-levodopa and Methyldopa?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor blood pressure, including orthostatic readings, and watch for changes in parkinsonian control or mental status. Reduce the antihypertensive dose if symptomatic hypotension occurs, or choose a different antihypertensive.
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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