Carbidopa and levodopa and Selegiline interaction
Carbidopa and levodopa and Selegiline: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Carbidopa and levodopa (Duopa) label · effective 2026-03-19
DUOPA is contraindicated in patients who are currently taking a nonselective monoamine oxidase (MAO) inhibitor (e.g., phenelzine and tranylcypromine) or have recently (within 2 weeks) taken a nonselective MAO inhibitor.
DUOPA is contraindicated in patients taking nonselective monoamine oxidase (MAO) inhibitors ( 4 )
Monoamine Oxidase (MAO) Inhibitors The use of nonselective MAO inhibitors with DUOPA is contraindicated [see Contraindications ( 4 ) ] .
The use of selective MAO-B inhibitors (e.g., rasagiline and selegiline) with DUOPA may be associated with orthostatic hypotension.
Discontinue use of any nonselective MAO inhibitors at least two weeks prior to initiating DUOPA.
From the Selegiline (ZELAPAR) label · effective 2021-06-01
Decreasing the dose of levodopa may lessen dyskinesia.
Dyskinesia ZELAPAR may potentiate dopaminergic side effects of levodopa and may cause dyskinesia or exacerbate preexisting dyskinesia.
…patients can experience intense urges to gamble, increased sexual urges, intense urges to spend money, binge eating, and/or other intense urges, and the inability to control these urges while taking one or more of the medications, including ZELAPAR, that increase central dopaminergic tone and that are generally used for the treatment of Parkinson’s disease.
Falling Asleep During Activities of Daily Living and Somnolence Patients with Parkinson’s disease treated with ZELAPAR or other drugs increasing dopaminergic tone have reported falling asleep while engaged in activities of daily living, including the operation of motor vehicles, which sometimes resulted in accidents.
Dopaminergic Antagonists It is possible that dopamine antagonists, such as antipsychotics or metoclopramide, could diminish the effectiveness of ZELAPAR.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.