Evaluation of the opioid addiction test in an out-patient drug dependency unit

Background The opioid addiction test is based on the measurement of pupil d ilatation in opioid-dependent people in response to conjunctivally applied naloxone hydrochloride. A positive response (pupil dilatation) indicates th at the subject is dependent on opioids. Aims To evaluate the test in an out-patient setting and to identify factors affecting its outcome. Method Pupil size was measured using binocular pupillometry in 100 new pati ents attending an out-patient clinic for assessment and treatment of opioid use. Measurement was repeated 40 minutes after the unilateral instillation of naloxone drops into the conjunctival sac. Results We performed 127 tests, of which 103 (81.1%) were positive. Males. and those not on methadone at the time of the test, were more likely to hav e a negative test result. Conclusions The opioid addiction test proved to be a very useful tool for t he rapid diagnosis of opioid dependence in the out-patient clinic. Speciali st pupillometric equipment increases the number of patients correctly ident ified as opioid-dependent on the first visit. but is not essential. Declaration of interest The study was funded by the Medical Research Counci l. Eye drops were prepared by Penn Pharmaceuticals and the pharmacy of St G eorge's Healthcare NHS Trust.