Institute study: Visine as a date-rape drug

Study identifies overdose level for Visine as a date-rape drug

Mary Carr, MDTetrahydrozoline eye drops, sold under the brand name Visine&ref;, have been implicated as a "date-rape drug." However, up until Mary Carr’s internal-grant funded study, "Tetrahydrozoline (Visine) Concentrations in Serum and Urine During Therapeutic Ocular Dosing: A Necessary First Step in Determining an Overdose," no studies had been done to establish concentrations of the drug when used according to manufacturer recommendations.

To establish parameters that could be used in court in Visine-associated rape cases, Carr, an emergency medicine physician at Regions Hospital, and colleagues placed two drops of Visine’s original formula into the eyes of 10 healthy volunteers and repeated the dosing at 4, 8 and 12 hours. Blood and urine samples were collected 2, 5, 9, 13 and 24 hours after application and analyzed for concentrations of tetrahydrozoline.

The drug was detectable in both serum and urine after administration. Absorption varied among subjects. At 24 hours, all patients still had detectable urine levels of tetrahydrozoline.

The results established that, when used as intended on the label, tetrahydrozoline was detectable in both serum and urine up to 12 hours after the last dose. A level greatly exceeding that amount would suggest intentional use as a date-rape drug or accidental ingestion.

When used as a date rape drug, tetrahydrozoline is often surreptitiously placed in a victim’s drink. It takes just one small bottle to sedate an adult, rendering them less able to resist assault. Visine is an over- the-counter medication that many people carry in their pocket, so it is rarely viewed as a potential weapon.

Thanks to this study, it’s possible to determine whether the concentration of tetrahydrozoline in a victim’s serum and urine is consistent with routine use of the medication or whether an intentional or unintentional overdose occurred. The study was published in the November 2011 issue of the Journal of Clinical Toxicology. Carr’s co-investigators were Kristin Engebretsen, PharmD; Benjamin Ho, MD; and Chris Anderson, MPH.