Methylphenidate abuse in Texas, 1998-2004.

Methylphenidate is a stimulant used in the treatment of attention deficit hyperactivity disorder in children and is subject to abuse. This study describes the patterns of methylphenidate abuse and drug identification (ID) calls received by several poison control centers in Texas. Cases were calls involving methylphenidate received by Texas poison control centers during 1998-2004. Drug ID and drug abuse calls were assessed by call year and geographic location. Drug abuse calls were then compared to all other human exposure (nonabuse) calls with respect to various factors. Of 6798 calls received involving methylphenidate, 35% were drug IDs and 56% human exposures. Of the human exposures, 9% involved abuse. The number of drug ID calls and drug abuse calls received per year both declined during the first part of 7-yr period but then increased. Male patients accounted for approximately 60% of both drug abuse and nonabuse calls. Adolescent patients comprised 55% of drug abuse calls and children less than 13 yr old comprised 62% of nonabuse calls. Although the majority of both types of human exposures occurred at the patient's own residence, drug abuse calls were more likely than non-abuse calls to involve exposures at school (15% vs. 6%) and public areas (3% vs. 0.4%). While drug abuse calls were less likely than nonabuse calls to present with no clinical effects (29% vs. 52%), they were more likely to show more serious medical outcomes. Methylphenidate abusers are more likely to be adolescents. Methylphenidate abuse as compared to other exposures is more likely to occur outside of the person's home and to involve more serious medical outcomes.