THE NALOXONE CONJUNCTIVAL TEST - AN UNDERUSED TOOL - A REVIEW OF THE AVAILABLE DATA

There is currently no simple and morbidity-free procedure available to determine opiate dependence in patients. There is preliminary evidenc e, however, that the naloxone conjunctival rest may be useful in this regard. This test consists of instilling a drop of saline solution of naloxone hydrochloride (an opiate-receptor antagonist) into the subjec t's eye. This causes significant homolateral mydriasis (anisocoria) in the eye of a chronic opioid-dependent subject and not in that of a no n-dependent subject. We reviewed the international literature on the n aloxone conjunctival test using the Medline database and a manual sear ch of major scientific journals specialized in the field of substance abuse. Up to March 1995, we identified six articles dealing specifical ly with the use of opiate antagonist ophthalmic solutions in populatio ns of chronic opioid addicts. Four of the articles reported the occurr ence of mydriasis when a solution of naloxone is used in opioid addict s. Two of the articles reported that there was no differential change in pupil size when the naloxone solution is used; however, one study u sed a much weaker and the other a much stronger solution of naloxone t han reported in the other studies. From our review of the literature, it appears that the naloxone conjunctival test holds great promise as a simple and morbidity-free method of resting for chronic opioid addic tion and, therefore, it should be studied further and its usage eventu ally developed.