Benzodiazepines (part 1) – Overview

Dr. Joseph E. Graas, Scientific Director
Dr. Edward Moore, Medical Director

The Benzodiazepines are a class of drugs with sedative, depressant, anticonvulsant, and muscle relaxant properties.  The “mood altering” effect of the Benzodiazepines was discovered by Leo Sternbach in 1955.  Hoffman LaRoche, in a concerted research effort to discover drugs that could be formulated and used for their beneficial psychoactive properties, released Librium in 1960 after FDA clearance.  Three years later Valium was released and for nearly two decades was the most prescribed medication in the United States.  There are currently some 36 biologically active drugs in the Benzodiazepine family.

The main use of the Benzodiazepines is in the treatment of anxiety (short-term or disabling), insomnia and some stress-related ailments.  The long-term use of these medications produces tolerance and dependency, and in some cases, addiction.

Benzodiazepines are a safer group of compounds when compared to the class of Barbiturates  (Amobarbital, Phenobarbital,  Secobarbital, etc.)  and  the tricyclic antidepressants  (Amitryptline, Desimipramine, Imipramine, etc.), and they have all but replaced these other medications.

The below table lists general information on the most common Benzodiazepines.  Benzodiazepines are typically classified as belonging to one of three categories: short, intermediate or long-acting.  The short-acting Benzodiazepines have half-lives of less than 6 hours; the intermediate have half-lives of 6 to 10 hours; and the long-acting have half-lives greater than 10 hours.  This is in terms of the residual sedative the patient feels after the time period.

In the table, the most frequently prescribed Benzodiazepines to an outpatient population are shown in capital letters.  At SDRL, these Benzodiazepines are the ones analyzed for when a GC/MS confirmation is requested.

The April issue of Toxicology Times will focus on  interpreting Benzodiazepine laboratory drug-testing results.