Benserazide

When levodopa is used by itself as a therapy for treating Parkinson's disease, its ubiquitous metabolism into dopamine is responsible for a resultant increase in the levels of circulating dopamine in the blood and to various extracerebral tissues. This can result in a number of side effects like nausea, vomiting, or even cardiac arrhythmias that may diminish patient adherence . A decarboxylase inhibitor like benserazide is consequently an effective compound to combine with levadopa as it is incapable of crossing the blood-brain barrier itself but acts to prevent the formation of dopamine from levadopa in extracerebral tissues - thereby acting to minimize the occurrence of extracerebral side effects . Levodopa/benserazide combination products are used commonly worldwide for the management of Parkinson's disease. In particular, although the specific levodopa/benserazide combination is formally approved for use in Canada and much of Europe, the FDA has approved another similar levodopa/dopa decarboxylase inhibitor combination in the form of levodopa and carbidopa. Moreover, the European Medcines Agency has conferred an orphan designation upon benseraside since 2015 for its potential to be used as a therapy for beta thalassaemia as well .

The primary therapeutic use for which benserazide is currently indicated for is as a combination therapy with levadopa for the treatment of Parkinson's disease in adults > 25 years of age, with the exception of drug-induced parkinsonism . At certain doses, the combination product of levodopa and benserazide may also be used to treat restless legs syndrome, which is sometimes associated with Parkinson's disease . There have also been some studies that have prompted the European Medicines Agency to confer orphan designation upon benserazide hydrochloride as a potential therapy for beta thalassaemia . Although studies are ongoing, no evidence has been formally elucidated as of yet .

• Parkinson's Disease (PD)