More than meets the eye: a scoping review on the non-medical uses of THZ eye drops

Abstract

AbstractTetrahydrozoline is an alpha agonist imidazole derivative found in over-the-counter decongestive eye and nasal drops. The drug was patented in 1954 and was available for medical use in 1959. This drug recently gained the attention of law enforcement as it has been utilized in criminal activity such as homicide and drug-facilitated sexual assault. The aim of this scoping review is to scope the literature for all mentions of tetrahydrozoline eye/nasal drops use in a non-medical context to delineate areas of future research and development. We used Google Scholar and PUBMED/Medline databases to search for non-medicinal and criminal uses of THZ. The search word used was “tetrahydrozoline.” A total of 15 articles matched our criteria. Among the case reports, two (11.1%) cases reported on drug-facilitated sexual assault, and two (11.1%) cases used THZ eyedrops to attempt suicide. Incidental ingestion of THZ eyedrops was reported in eight (44.4%) cases, three (16.7%) cases of attempted murder were reported, two (11.1%) cases of intentional ingestion were reported, and one (5.5%) case was a combination of drug-facilitated sexual assault and attempted murder. The most common clinical presentation was unexplained and resistant bradycardia and hypotension. THZ eye drops can be used to produce false negative results on drug tests. This study recognizes that THZ can be used in non-medicinal and criminal uses. There is room for future research and development. More studies should be conducted to better understand the mechanism of action, therapeutic window, and toxicity levels among various age groups at different methods of intake and to find an effective treatment in case of overdose. Eyedrop and nasal decongestant bottles should be designed with child proofing to prevent incidental ingestion and should contain warning labels. A fast and alternative test to GC/MS can be developed to ease the diagnosis of THZ toxicity. Purchases of this medication may need to be monitored.