Safinamide has both dopaminergic properties (highly selective and reversible inhibition of monoamine oxidase-B) and non-dopaminergic properties (selective sodium channel blockade and calcium channel modulation, with consequent inhibition of excessive glutamate release). It is added to the use of L-dopa or dopamine agonists. For more information go to Xadago : http://www.ema.europa.eu/ema/index.jsp?curl=pages/medicines/human/medicines/002396/h uman_med_001847.jsp&mid=WC0b01ac058001d124
The use of L-dopa is limited by wearing off and dyskinesias. The objective of this study was to investigate the efficacy and safety of safinamide in L-dopa treated patients who had motor fluctuations. If no tolerability issues arose by day 14, the starting dose, 50 mg, was increased to 100 mg. When taking safinamide, the mean change in daily on time without dyskinesia 2.80 hours. However, this was not much different from the effect that a placebo had. The most frequently reported adverse event was dyskinesia (14%], and as a severe event (2%). These results are consistent with previous studies in which the increase in "on" time beyond that of a placebo was only 40 minutes for 50mg safinamide, and 50 minutes for 100mg safinamide.
Reference : JAMA Neurology  74 (2) : 216-224 (A.H.Schapira, S.H.Fox, R.A.Hauser, J.Jankovic, W.H.Jost, C.Kenney, J.Kulisevsky, R.Pahwa, W.Poewe, R.Anand)
Complete abstract : http://www.ncbi.nlm.nih.gov/pubmed/27942720