Brimonidine tartrate poisoning in children: frequency, trends, and use of naloxone as an antidote.

Background: Brimonidine tartrate, a centrally acting selective alpha-2 adrenergic agonist with a toxicity that is often compared with that of clonidine, is used as eye drops to lower intraocular pressure in glaucoma. We investigated characteristics of childhood exposures to brimonidine-containing products.

Methods: All brimonidine exposures in children 0 to 5 years of age between 1997 and 2005 were retrieved from the American Association of Poison Control Centers' Toxic Exposure Surveillance System database and the US Food and Drug Administration's Medwatch Adverse Events Reporting System. The design of the study was retrospective, and the main outcome measures were frequency of exposures over time, reason, symptoms/signs of toxicity, dose, management site, treatment, and outcome.

Results: There were 413 brimonidine reports in the Toxic Exposure Surveillance System and 340 in the Adverse Events Reporting System during the 9 years under study, of which 185 Toxic Exposure Surveillance System reports involved children < or =5 years of age versus 15 cases in the Adverse Events Reporting System. There were no deaths. The peak age of poisoning in the Toxic Exposure Surveillance System pediatric cases was 2 years of age, and circumstances were unintentional poisoning in 176 cases, usually by ingestion (84.3%). Common symptoms in 176 children included drowsiness (40.9%), ataxia (4.5%), pallor (4.5%), irritability (4.0%), hypotension (4.0%), bradycardia (4.0%), miosis (3.4%), and respiratory depression (3.4%). Of the 176 unintentional pediatric poisonings, 73 children were observed at home and 103 were seen at a health care facility; 28 were hospitalized and 11 received naloxone. Of the 15 pediatric cases in the Adverse Events Reporting System data set, all were hospitalized, and 13 had ocular exposures only.

Conclusions: All children < or =5 years of age with confirmed brimonidine ingestions should be medically evaluated and monitored for an extended period. Indications for the use of naloxone in brimonidine poisoning remain uncertain.