Depressants: Sedative-Hypnotic-Tranquilizing Drugs—From Errant Yeast to Halcion and Its Relatives

The agents we will consider in this chapter are a disparate bunch, but they are united in that most can induce a mild state of intoxication that many of us find to be pleasant; social drinkers of ethyl alcohol are familiar with the phenomenon. The darker side of these drugs is that all can induce physical dependence with a characteristic and sometimes life-threatening withdrawal syndrome. In addition, they are often agents of addiction; alcoholism is a prime example. Further uniting these drugs is the relatively recent recognition of a common mechanism of action. Their current primary medical uses are in anesthesiology, as anticonvulsants, and in the treatment of anxiety and sleep disorders. For many years, drugs of this class were referred to as sedative- hypnotics. Sedation implies the induction of a state of calmness, while hypnosis refers to sleep. However, with the discovery of meprobamate (Miltown), and the benzodiazepines, for example, Valium, which we will consider later, a third term was introduced. These drugs were to be called tranquilizers to distin­guish them from earlier sedative-hypnotics. But whatever the drugs are called, the fact is that for most there is a dose-related continuum of action beginning with a state of calmness (call it tranquility, if you wish) to sleep, and, finally, for some, coma and death. An illustration of the long- recognized connectedness of sedation, hypnosis, and anxiety was provided us by Henry Behrend. He describes his patient as . . . . . . a gentleman, forty years of age. . . . He was of a most excitable and nervous temperament, and was engaged in mercantile transactions of great magnitude, the extent of which seemed quite to overwhelm him. . . . He had lost his natural sleep, was harassed and fatigued during the day, and sought my opinion as to whether he ought not at once to withdraw from business, although the sacrifice entailed thereby would be very great, and he was most anxious to avoid it. . . .