Sedatives and Hypnotics

Sedatives and hypnotics depress or inhibit brain activity and produce drowsiness, sedation, or sleep; relieve anxiety; and lower inhibition. Although the depressant compounds do not share a common neural mechanism of action, most of them either decrease the metabolic activity in the brain or increase the transmission of the principal inhibitory neurotransmitter of the brain, gamma-aminobutyric acid (GABA).

All sedatives have the potential for addiction and dependency. Common depressants include barbiturates, such as Seconal; benzodiazepines, such as Xanax and Valium (commonly called minor tranquilizers); nonbarbiturate sedatives, such as methaqualone; newer nonbenzodiazepines, such as buspirone, antihistamines, and anesthetics; and alcohol. In low doses, alcohol can act as a stimulant; however, with increased dosage alcohol's main effect is depressive.

Excerpt from Psychoactive Drugs

Sedative-Hypnotic Drug, chemical substance used to reduce tension and anxiety and induce calm (sedative effect) or to induce sleep (hypnotic effect). Most such drugs exert a quieting or calming effect at low doses and a sleep-inducing effect in larger doses. Sedative-hypnotic drugs tend to depress the central nervous system. Since these actions can be obtained with other drugs, such as opiates, the distinctive characteristic of sedative-hypnotics is their selective ability to achieve their effects without affecting mood or reducing sensitivity to pain.

Definition retrieved May 23, 2012 from Encyclopaedia Britannica, Sedative-Hypnotic