Carbidopa Pharmacology

Carbidopa inhibits aromatic-L-amino-acid decarboxylase (DOPA decarboxylase or DDC), an agitator important in the biosynthesis of L-tryptophan to serotonin and in the biosynthesis of L-DOPA to dopamine (DA). DDC exists both alfresco of (body periphery) and aural the borders of the blood–brain barrier.

Carbidopa is used in the analysis of, a part of added diseases, Parkinson's ache (PD), a action characterized by afterlife of dopaminergic neurons in the substantia nigra. Increased dopamine accessible may access the capability of the actual neurons and allay affection for a time. The pharmacologic cold is to get an exogenous dopamine-precursor known as levodopa/L-DOPA into the dopamine-deficient accuracy of PD patients. Levodopa/L-DOPA can cantankerous the blood–brain barrier, but dopamine cannot. The use of carbidopa seems counter-intuitive in Parkinson's ache (PD) in that it prevents DDC about-face of levodopa/L-DOPA to dopamine. However, exogenously provided, levadopa/L-DOPA gets metabolized peripherally to its active metabolite dopamine afore extensive the blood–brain barrier. Therefore, the PD brain, which is amiss in dopamine, will not accept as abundant of its prodrug forerunner levodopa/L-DOPA due to borderline DDC breakdown. However, carbidopa can abatement borderline DDC about-face of levodopa/L-DOPA afore it crosses the blood–brain barrier. Carbidopa acts as a borderline DDC inhibitor, as carbidopa, itself, cannot cantankerous the blood–brain barrier. In added words, carbidopa has no aftereffect on academician DDC about-face of levodopa/L-DOPA to dopamine. Ultimately, a greater admeasurement of the exogenously provided levodopa/L-DOPA alcove the brain. Commercially, carbidopa/levodopa combinations are accessible in the analysis of axial dopamine deficiencies.