Definition

A hydrazine derivative of dopa. Carbidopa is a peripheral dopa decarboxylase inhibitor that is used as an adjunct to levodopa administration to prevent peripheral biosynthesis of levodopa to dopamine, thereby reducing peripheral side effects. Carbidopa does not penetrate the blood brain barrier so that levodopa, after it reaches the brain, can be metabolized to dopamine by dopa decarboxylase where it exerts its effect on dopamine receptors.