Pharmacological Aspects of Drug Dependence

Abstract

Publisher Summary Drug dependence in man does not develop to many of the classes of drugs that induce tolerance, and tolerance does not develop to some of the drugs to which man may become dependent. Both tolerance and dependence develop to two major classes of central nervous system depressants, narcotic analgesics and the sedative hypnotics. The clinical techniques for evaluating a drug's capacity to induce physical dependence have been discussed in this chapter. The factors that influence the development of physical dependence and the postulates concerning the mechanism underlying its development have also been reviewed. The factors that favor the optimal development of physical dependence to the narcotic analgesics are related to the nature of the particular drug, to the manner of its administration, and to the species. Although, the clinical literature dealing with psychogenic or psychic dependence is enormous, only recent laboratory studies have initiated to determine whether this phenomenon could be demonstrated in animals. The search for an analgesic drug devoid of morphine's undesirable properties continues unabated. A morphine derivative has been found in which the analgesic property has been dissociated from the most undesirable property of all-that of producing physical dependence. A variety of other drugs have been produced that resemble morphine, or more frequently codeine, in their over-all spectra of pharmacological actions. A variety of antagonists have been developed in the morphinan and benzomorphan series. Many of these have been assayed as analgesics in man. It is recently found that some of the narcotic analgesics produce analgesia but do not produce physical dependence. Moreover substances that are effective antitussives and that completely lack the capacity to induce physical dependence have also been discovered in recent years.