Abstract
The elderly population is increasing in Japan both in absolute numbers and as a faction of the whole population. The use of medications also increases significantly with age. However the physiological characteristics of elderly patients contribute to an increased risk of adverse reactions of various drugs. These are paticularly likely to occnr with drugs that act on the central nervous system, such as neuroleptics, antidepressant agents and anxiolytic sedative-tranquilizer. A higher incidence of adverse reactions in the elderly may be the result of exessive blood or end organ level of drug due to the alteration of pharmacokinetic profile in the aged patients. In various physical factors in the aged, a chronological aging was considered to be important to alter the pharmacokinetic profile. On the other hand, it has bacome apparent that nonspecific morbid conditions such as acute infection and malnutrition are also an important factor in decreasing the hepatic metabolism of drug. From these view points, this paper intends to discuss the effect of age on the pharmacokinetics of various psychotropic drugs including neuroleptics, antidepressant and benzodiazepine drugs. In addition, the author suggests that multimorbidity frequently accompanied with aging process may suppress the hepatic drug metabolism in the elderly patients with psychiatric disorders.
