Benzodiazepines in Miami-Dade County, Florida driving under the influence (DUI) cases (1995-1998) with emphasis on Rohypnol: GC-MS confirmation, patterns of use, psychomotor impairment, and results of Florida legislation.

Benzodiazepines are central nervous system depressant drugs often detected in biological samples from driving under the influence (DUI) offenders. They are associated with marked psychomotor impairment and represent up to 20% of all Miami-Dade County, Florida DUI urine samples analyzed in our laboratory annually. Flunitrazepam emerged in the mid-1990s as an illegal drug in the U.S. that was predominantly abused recreationally and associated with sexual assaults. Immunoassays for benzodiazepines do not discriminate between different benzodiazepines, and certain metabolites, such as 7-aminoflunitrazepam, react poorly with immunoassay reagents. A simple and sensitive method for the detection and quantitation of major benzodiazepines and metabolites by gas chromatography with mass selective detection is presented. This method was used to confirm benzodiazepines in general and flunitrazepam in particular. Data collected over a three-and-a-half-year period are summarized. Whereas flunitrazepam was present in up to 10% of DUI cases in 1995 and 1996 and had fast become the most frequently encountered benzodiazepine in Miami-Dade County DUI-related urine samples, a dramatic drop in case numbers followed the legal reclassification of the drug as a Schedule I substance in Florida in February 1997. Flunitrazepam was often used alone or in combination with cannabis and cocaine. A recent rise in clonazepam cases coincides with the decrease in flunitrazepam confirmation and may indicate a new trend in the abuse of benzodiazepines in South Florida.