Safinamide, sold under the brand name Xadago, is a medication used as treatment for Parkinson's disease with "off" episodes; it has multiple modes of action, including the inhibition of monoamine oxidase B.

[4] Common adverse events in clinical trials (in more than 1% of people) included nausea, dizziness, tiredness, sleeplessness, orthostatic hypotension (low blood pressure), and headache.

[8][9] Expected overdose effects are hypertension (high blood pressure), orthostatic hypotension, hallucinations, psychomotor agitation, nausea, vomiting, and dyskinesia.

In studies, a single person was suspected to have overdosed for a month; symptoms were confusion, drowsiness and mydriasis (dilation of the pupils) and subsided completely after the drug was discontinued.

[8] Another theoretical interaction is with drugs with affinity to the transporter protein ABCG2 (also known as BCRP), such as pitavastatin, pravastatin, ciprofloxacin, methotrexate, and diclofenac; a study with the latter has shown no clinical relevance.

[1] There are no relevant interactions related to cytochrome P450 (CYP) liver enzymes, although one inactivation pathway of safinamide seems to be mediated by CYP3A4.

[8] Like the older antiparkinson drugs selegiline and rasagiline, safinamide is a selective monoamine oxidase B inhibitor, reducing degradation of dopamine; in contrast to the other two, its action is reversible.

[17] In the course of a major restructuring in the same year, all rights for safinamide were transferred to the newly formed company Newron Pharmaceuticals, which developed the drug until it was sold to Merck KGaA in 2006.

[19] In October 2011 Merck, now Merck-Serono, announced that they would give all rights to develop the compound back to Newron because they wanted to prioritise other projects and had corrected their estimates for safinamide's market potential downwards.

[22] In spring 2015, following a commercial agreement between Newron and the Italian pharmaceutical company Zambon, the European Medicines Agency (EMA) approved the drug.