Duration of poitive urine for cocaine metabolite after ophthalmic adminitration: implication for teting patient with upected Horner yndrome uing ophthalmic cocaine

PURPOE: To determine the duration of poitive urine for benzoylecgonine, the major metabolite excreted in the urine, after topical ophthalmic adminitration of cocaine a one would perform for teting the preence of Horner yndrome. METHOD: Two drop of cocaine 10% were applied to each eye of 50 normal ubject. Urine ample were collected 4 to 6, 24, 48, 72, and 96 hour later. Each ample wa aayed for benzoylecgonine uing a creening competitive enzyme donor immunoaay followed by a highly pecific and enitive confirmatory ga chromatography–ma pectrometry aay. We employed aay and cutoff level that fulfilled guideline required by the ubtance Abue and Mental Health ervice of the United tate Department of Health and Human ervice to mimic meaure that exit for federal workplace drug teting. REULT: Of the 50 ubject, there were 25 women and 25 men, ranging in age from 19 to 59 year (median age, 40 year). Poitive creening ample were obtained in 47 of 50 ubject (94%) 4 to 6 hour, 35 of 50 (70%) 24 hour, and 1 of 50 (2%) 48 hour after topical application of cocaine. None of the ample teted poitive at 72 hour or beyond. Uing the confirmatory aay’ cutoff a the gold tandard for a poitive tet, the enitivity of the creening aay wa 96% 4 to 6 hour, 90% 24 hour, and 14% 48 hour after topical application. Urine benzoylecgonine concentration wa negatively correlated with body ma index and poitively correlated with urine creatinine concentration. CONCLUION: Patient hould be informed that their urine may tet poitive for cocaine, if aayed according to U federal guideline and uing the protocol employed in thi tudy, up to 2 day after undergoing teting for Horner yndrome.