Carbidopa has 20 known drug interactions based on U.S. FDA drug labeling data. Of these, 3 are contraindicated combinations that should be avoided entirely. 2 are classified as major interactions requiring close medical supervision. Notable interactions include combinations with Monoamine Oxidase Inhibitors (Type A Or B), Rasagiline, Selegiline. Patients taking Carbidopa should inform their healthcare provider of all current medications — including over-the-counter drugs and supplements — to avoid potentially harmful combinations. Data sourced from OpenFDA and the NIH National Library of Medicine.
- Total
- 20
- Contraindicated
- 3
- Major
- 2
- Moderate
- 13
- Minor
- 2
Contraindicated (3)
- Carbidopa + Monoamine Oxidase Inhibitors (Type A Or B)— Contraindicated with carbidopa; see CONTRAINDICATIONS section.
- Carbidopa + Rasagiline— Concomitant therapy may be associated with severe orthostatic hypotension not attributable to carbidopa-levodopa alone.
- Carbidopa + Selegiline— Concomitant therapy may be associated with severe orthostatic hypotension not attributable to carbidopa-levodopa alone.
Major (2)
- Carbidopa + Carbidopa, Levodopa And Entacapone— May result in increased heart rates, possibly arrhythmias, and excessive changes in blood pressure. Metabolized by COMT.
- Carbidopa + Metoprolol Tartrate— Antihypertensive effect may be potentiated by metoprolol, increasing risk of hypotension.
Moderate (13)
- Carbidopa + Butyrophenones— Dopamine D2 receptor antagonists may reduce the therapeutic effects of levodopa; patients should be carefully observed f…
- Carbidopa + Diethylpropion Hydrochloride— Diethylpropion may interfere with antihypertensive effects; pressor effects may be additive.
- Carbidopa + Fluorodopa F18— AADC inhibitor that may increase Fluorodopa F18 bioavailability to the brain by inhibiting peripheral decarboxylase acti…
- Carbidopa + Iron Salts— Should be co-administered with caution; iron salts can form chelates with levodopa and carbidopa, reducing bioavailabili…
- Carbidopa + Isoniazid— May reduce the therapeutic effects of levodopa; patients should be carefully observed for loss of therapeutic response.
- Carbidopa + Levodopa— Carbidopa may potentiate the dopaminergic side effects of levodopa and may cause or exacerbate preexisting dyskinesia.
- Carbidopa + Metoclopramide— May adversely affect disease control through dopamine receptor antagonistic properties despite potentially increasing le…
- Carbidopa + Metoprolol— Antihypertensive effect of alpha-adrenergic agent may be potentiated by metoprolol.
- Carbidopa + Papaverine— Beneficial effects of levodopa in Parkinson's disease reported to be reversed; patients should be carefully observed for…
- Carbidopa + Phenothiazines— Dopamine D2 receptor antagonists may reduce the therapeutic effects of levodopa; patients should be carefully observed f…
- Carbidopa + Phenytoin— Beneficial effects of levodopa in Parkinson's disease reported to be reversed; patients should be carefully observed for…
- Carbidopa + Pyridoxine Hydrochloride— Pyridoxine may be used concurrently with carbidopa-levodopa preparations, as carbidopa prevents pyridoxine from antagoni…
- Carbidopa + Risperidone— Dopamine D2 receptor antagonists may reduce the therapeutic effects of levodopa; patients should be carefully observed f…
Minor (2)
- Carbidopa + Ropinirole— Coadministration with L-dopa and ropinirole had no effect on steady-state pharmacokinetics of ropinirole.
- Carbidopa + Tolcapone— No effects on pharmacokinetics of carbidopa observed despite tolcapone's potential to influence COMT substrate metabolis…