Mydriatic Response to Topical Naloxone in Opiate Abusers

Abstract

Naloxone hydrochloride eyedrops 1 mg/ml dilated the pupils of 36 out of 47 opiate addicts on methadone maintenance treatment, without precipitation of acute withdrawal effects, but not those of healthy unmedicated subjects. The response in addicts was attenuated by certain ancillary treatments and by withdrawal of methadone treatment. The size of the response suggests some potential clinical use for topical naloxone as a diagnostic test of current opioid influence and possibility of physical dependence. The local mydriatic response, which was restricted to the treated eye, indicates that the effect of opiates on the pupil in man is determined, at least in part, by a peripheral action.

The opiate addiction test: a clinical evaluation of a quick test for physical dependence on opiate drugs.

“…Using the measurement conditions and methods described in this study, the number of false negative results has been reduced from the 25% reported in previous studies carried out in this department [1,2] to 20%, indicating the necessity of precision pupillometry and critical timing of the pupillometric measurements in determining opiate dependent individuals from a random population of subjects. The Opiate Addiction Test is currently being used in our Drug Dependency Unit to validate these findings, and to attempt to increase the sensitivity of the test still further.…”

“…The mydriasis following the instillation of naloxone eyedrops in opiate dependent individuals has been previously demonstrated [1,2]. Naloxone does not produce mydriasis in subjects who have not received an opiate [1] or in subjects who have received an opiate but who are not physically dependent [2]. In the previous reported studies approximately 25% false negative responses (known opiate dependent subjects who showed no naloxone induced mydriasis) were noticed.…”

“…All opiates induce pupillary constriction whether the individual is physically dependent on them or not. The mydriasis following the instillation of naloxone eyedrops in opiate dependent individuals has been previously demonstrated [1,2]. Naloxone does not produce mydriasis in subjects who have not received an opiate [1] or in subjects who have received an opiate but who are not physically dependent [2].…”

“…Significant mydriasis in response to topically applied naloxone solution has been demonstrated in previous studies carried out in this department [1,2]. In these studies pupil sizes were measured with a polaroid camera system before eyedrop instillation, and at 30 min and 45 min after eyedrop instillation (also at 60 min in [1]).…”

“…In these studies pupil sizes were measured with a polaroid camera system before eyedrop instillation, and at 30 min and 45 min after eyedrop instillation (also at 60 min in [1]). …”