2.2.7. Amantadine
Although Amantadine has been available for nearly four decades (it was originally marked as an antiviral agent), little is known about its mechanism of action. It has been thought that Amantadine has both anticholinergic and anti-glutamatergic properties and for this reason is the only antiparkinsonian drug that could improve the characteristic l-dopa induced dyskinesias often present in the latter stage of PD [97]. However, Amantadine can be useful in the first stages of PD even though its effects are more appreciable in the first months of treatment. Moreover, Amantadine use could be associated with several side effects such as visual hallucinations, ankle edema, and livedo reticularis, which can influence therapeutic compliance. The usual dose is 100 mg two times per day but dose adjustment up to 200 mg two times per day might be allowed.