Intravenous Abuse of Tropicamide in Opioid Use Disorder: Presentation of 2 Cases.

BACKGROUND: Tropicamide is an antimuscarinic ophthalmic solution used to produce short-acting mydriasis and cycloplegia. Topical abuse of ophthalmic solutions has been reported, but intravenous (IV) abuse of tropicamide seems to be a new phenomenon. CASES: The authors present 2 patients with concomitant IV tropicamide abuse and opioid use disorder. Patients were hospitalized and started on buprenorphine/naloxone treatment for opioid withdrawal. Patients' reports about tropicamide effects are remarkable, as they claimed that tropicamide increased the efficacy of heroin while decreasing and delaying the withdrawal symptoms. DISCUSSION: Although anticholinergics have been known to be abused for their euphoric effects, these cases' motivation to use tropicamide seemed to extend beyond its euphoric effect and was also based on its interaction with heroin. It is feared that tropicamide abuse may become more frequent. Health professionals should be aware of this trend so that symptoms of misuse and intoxication can be recognized, and ophthalmologists should consider the abuse potential of anticholinergic eye drops when prescribing them.