Don?t take this drug again if you?ve ever had an allergic reaction to it. Taking it again could be fatal (cause death).If you have blurry vision or other confusion after taking amantadine, you should not drive or work in a situation in which you need to be alert or be able to move well. You should call your doctor if your Parkinson?s disease gets worse, if your movement disorder gets worse, or if your flu symptoms become more severe. If you?re taking amantadine for Parkinson?s disease, do not abruptly stop taking it. If you do, you may experience serious side effects, including agitation, hallucinations, slurred speech, and stupor depression. Dextroamphetamines, atomoxetine, methylphenidate, diphenhydramine, scopolamine, tolterodine, benztropine, triamterene-hydrochlorothiazide, quinine, quinidine.