Phenytoin toxicity from smoking crack cocaine adulterated with phenytoin.

Drugs of abuse often are adulterated with agents designed to lower cost or alter the intoxication. Recently, we began to hear of the intentional addition of phenytoin to crack cocaine. We report the cases of five patients with measurable phenytoin levels attributable to smoking crack cocaine adulterated with phenytoin. Three of these patients presented with signs, symptoms, and phenytoin levels consistent with phenytoin toxicity. Clinicians should be aware of this practice when faced with cocaine users with altered mental status, ataxia, or nystagmus.