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The term sedative-hypnotic refers to any drug designed to produce sedation and sleepiness. These drugs can be divided into the benzodiazepines (see Chapter 177, Benzodiazepines) and nonbenzodiazepines (Table 178-1).

Table 178-1 Nonbenzodiazepine Sedatives

Sedatives were some of the first class of agents to be used in modern medicine. Chloral hydrate, one of the oldest sedative-hypnotic agents, was originally synthesized in 1832. The first death attributed to this agent was reported in 1890.1 In the beginning of the 20th century, the barbiturates barbital and phenobarbital were introduced. As the toxicity of the barbiturate was recognized, the search for newer, safer drugs began.

The emergency physician is likely to encounter these nonbenzodiazepine sedative drugs as part of accidental or nonaccidental overdose, as well as in patients presenting after an assault or trauma. In 2008, the American Association of Poison Control Centers received reports of 27,705 exposures to nonbenzodiazepine sedatives; 13,054 were single drug exposures, and two deaths were reported.2

Three agents commonly used in the past have been removed from the legal U.S. and Canadian markets: ethchlorvynol, glutethimide, and methaqualone. In 1984, methaqualone was upgraded to a Schedule I drug by the U.S. Food and Drug Administration and the remaining U.S. manufacturer stopped production. In 1999, the U.S. manufacturers stopped production and sale of ethchlorvynol and glutethimide. However, unverified comments on the Internet suggest these drugs might be available to North American customers from locations in Eastern Europe, Africa, and Asia.

Many of these nonbenzodiazepines were developed and are marketed for the treatment of insomnia. The sedative effect of other agents, including antihistamines (e.g., diphenhydramine, doxylamine), antidepressants (e.g., amitriptyline, trazodone, and mirtazapine), and antipsychotics (e.g., quetiapine) are also used to promote sleep.

Buspirone was originally approved by the U.S. Food and Drug Administration for treatment of generalized anxiety in 1986.3 Other off-label uses include treatment of depression and nicotine dependence. Buspirone is a partial agonist at the serotonin-1A receptor and an antagonist of the dopamine-D2 receptor.4 The resultant effect on serotonin and dopamine neurotransmitter levels is complex, depending on the concentration of the drug and specific brain location. The reported noradrenergic effects are likely an indirect effect of the serotoninergic effect of buspirone.

Buspirone has a complex mechanism of action, but its primary effects are presumably due to suppression ...

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