Delirium with manic and psychotic features associated with amantadine.

While clinicians are familiar with psychosis as a complication in the long-term treatment with amantadine, rapid psychiatric complications are of much less concern. In the case presented, severe decompensation in mental status occurred within 48 h of initiation of standard doses of amantadine hydrochloride. Clinicians should be alert not only for delayed complications but also for early-onset mental decompensation in elderly patients with influenza A treated with amantadine.