What the FDA labels say about taking them together
Carbidopa and levodopa
Carbidopa's FDA label of July 2, 2020 names levodopa in its contraindications section; the levodopa label PlainMeds reads does not name carbidopa. The carbidopa label: “Nonselective monoamine oxidase (MAO) inhibitors are contraindicated for use with levodopa or carbidopa-levodopa combination products with or without carbidopa.”
Check it at the source: the carbidopa FDA label on DailyMed (effective July 2, 2020, Oceanside Pharmaceuticals); the levodopa FDA label on DailyMed (effective July 20, 2026, Merz Pharmaceuticals, LLC).
What does the carbidopa label say about levodopa?
Carbidopa label, contraindicationsNonselective monoamine oxidase (MAO) inhibitors are contraindicated for use with levodopa or carbidopa-levodopa combination products with or without carbidopa.
Carbidopa label, drug interactionsDrug Interactions Caution should be exercised when the following drugs are administered concomitantly with carbidopa given with levodopa or carbidopa-levodopa fixed dose combination products.
Carbidopa label, warningsIt is indicated for use with carbidopa-levodopa or levodopa. carbidopa does not decrease adverse reactions due to central effects of levodopa.
Source: FDA drug label (Carbidopa), NDA017830 (Aton), as published by Oceanside Pharmaceuticals, effective July 2, 2020 (SPL set d5204e5e-10ef-4758-8fc6-cb710048c687), via openFDA; the full label on DailyMed
What does the levodopa label say about carbidopa?
Levodopa's label (effective July 20, 2026) does not name carbidopa in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Inbrija), Merz Pharmaceuticals, LLC, effective July 20, 2026 (SPL set 077c0f39-a3a2-4b2b-a184-09131889dcfb), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Carbidopa | Levodopa | |
|---|---|---|
| Labeled for | Parkinson's disease | Parkinson's disease |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.536 per tablet 25 mg tablet | n/a |
| Shortage now | No current entry | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once