Extracerebral decarboxylase inhibitor

Extracerebral decarboxylase inhibitor is an inhibitory enzyme. It is used to inhibit the decarboxylation of L-DOPA to Dopamine outside the brain, i.e. in the blood. This is primarily co-administered with L-DOPA to combat Parkinsons Disease. Administration can prevent common side-effects, such as nausea and vomiting, as a result of interaction with D2 receptors in the vomiting center (or cheomoreceptor trigger zone) located outside the blood–brain barrier.

Examples of extracerebral decarboxylase inhibitors include Carbidopa and Benserazide.