Pharmacologic Basis for Developing Rational Drug Regimens for Elderly Patients

Abstract

Changes in responsiveness with age have been observed for autonomic drugs (agonists as well as antagonists, analgesics, anticonvulsants, bronchodilators, hypoglycemics, corticosteroids, and virtually every other group of drugs). As indicated earlier, however, this review is not meant to present an exhaustive treatment of the area, but rather to focus attention on the factors that contribute to alterations in sensitivity. As a secondary aim, the review serves to focus attention on the problem of adverse drug reactions, particularly those related to the practice of polypharmacy, which compounds the problem through drug interactions. As indicated in the introduction, adverse drug reactions (undesired or unwanted effects of drugs) occur more frequently in the older patient than in the young one. In the elderly, this relates to increased use of drugs, polypharmacy, diminution in the function of organs which play a role in drug distribution and elimination, and poor patient compliance. Drugs which most often result in adverse reactions in the elderly have been listed by Lamy (Table 1). It is of significance that this list includes many drugs that are obtainable over the counter without prescription, such as aspirin and antacids. Because of the widespread practice of polypharmacy in the elderly, there is an increased potential for drug interactions. Examples of drugs and the mechanisms whereby interactions occur, which are of particular significance in geriatric therapeutics, are provided in Table 3. Since monographs summarizing drug interactions have been available for a number of years, it is somewhat surprising that the magnitude of the problem is still so great. It appears clear that the more we understand about the basic changes that occur in the physiology, biochemistry, and structure of an organism as it ages, and the more we learn about basic pharmacologic principles, the better we can combine the knowledge toward the development of rational therapeutic drug regimens for the geriatric patient. For more detailed discussion, the reader is referred to Caird et al., Kayne, Vestal, Lamy, and Poe and Holloway. A summary of the major principles in prescribing drugs for the elderly, quoted from Riley, is provided in Table 2.