Drug reference

Carbidopa

Dopamine Agonist · Antiparkinsonian

Dopamine AgonistAntiparkinsonian

CDSCO approvedSchedule H

EXCRETION

—

not curated

INTERACTIONS

—

none in our sources

PREGNANCY

—

not curated

Mechanism

Carbidopa acts as a peripheral competitive inhibitor of the enzyme dopa decarboxylase. By preventing the extracerebral metabolism of exogenous levodopa into dopamine, it significantly increases the amount of levodopa available to cross the blood-brain barrier. This enhanced central delivery of levodopa allows for greater dopamine synthesis within the brain, thereby improving motor symptoms in Parkinson's disease and reducing peripheral dopaminergic adverse effects.

Indications

Parkinson's disease (in combination with levodopa for motor symptoms affecting quality of life in early stages)Advanced levodopa-responsive Parkinson's disease with severe motor fluctuations and hyperkinesia or dyskinesia (in levodopa-carbidopa intestinal gel)Administered in combination with levodopa to treat PDReduces formation of DA in the periphery, preventing nausea and orthostatic hypotensionUsed as an adjuvant to levodopa in Parkinson's disease

Dosing

Adult: Adult: Initially 150 mg daily in divided doses, then. increased in steps of 50 mg every 2–3 days, adjusted. according to response; usual dose 150–300 mg daily in. divided doses; maximum 400 mg per day. Orphenadrine hydrochloride 10 mg per 1 ml Orphenadrine