Amantadine Intoxication Reversed by Physostigmine

To the Editor: Amantadine hydrochloride, a unique compound with a half-life of 24 hours,¹ has antiviral A₂ activity² and is useful in idiopathic Parkinsonism³ and neuroleptic-induced extrapyramidal symptoms (EPS).⁴ A review of its mechanism of action in movement disorders suggests that amantadine may increase available dopamine by increasing synthesis, augmenting release and inhibiting cellular reuptake.⁵ Intoxication with amantadine, either by overdose or by impaired renal function, produces a delirium that has no specific antidote.³⁶⁷ In a 67-year-old man with hypertension and episodes of atrial fibrillation, but normal renal function, delusions of grandeur, hyper-activity and mild dementia, EPS developed when he. No extract is available for articles shorter than 400 words.