Amantadine effectiveness in multiple system atrophy and progressive supranuclear palsy.

Progressive Supranuclear palsy (PSP) and multiple system atrophy (MSA) each respond poorly to most anti-parkinsonian drugs. We assessed PSP and MSA cases seen between 1970 and 1996 for response to amantadine (Amd) 100 mg twice daily. Of 13 MSA cases (six females, seven males), eight (61.5%) improved, four (30.8%) did not benefit and one had insufficient documentation. Adverse effects were observed in three (23.1%) cases. Of 14 PSP (three females, 11 males), six (42.9%) had some improvement, five (35.7%) had no benefit, and three (21.4%) had inadequate documentation. Adverse effects were noted in three (28.6%) cases. Improvement is likely related to NMDA antagonist properties of Amd. We recommend consideration of Amd in the management of both PSP and MSA.