What is the first line drug for PD & what is it?
Why is Carbidopa combined w/ this drug?
Levodopa: precursor of dopamine NT.
Carbidopa, a decarboxylate inhibitor (converter), is added to Levodopa so that it does not convert Levodopa to dopamine before entering the BBB.
The two must cross the BBB. Then, Levodopa is decarboxylated into dopamine by carbomide and dopamine can act on the CNS.
Carbidopa also prevents the peripheral metabolism of levodopa, therefore, less levodopa is needed and SFX are diminished.