Mechanism of action
In Parkinson’s disease there is depletion of dopamine in dopaminergic neurons in striatum. Levodopa is decarboxylated to dopamine by dopa decarboxylase in brain. In hypokinesia, rigidity are controlled earlier and tremors later on. Carbidopa : Acts by inhibiting peripheral dopa decarboxylase enzyme, therefore conversion of levodopa to dopamine is inhibited. Hence low dose of levodopa is required.