DRUG-THERAPY

Drug therapy for individuals of any age is difficult but prescribing f or older patients offers special challenges. Older people take about t hree times as many prescription medications as younger individuals do, mainly because of their increased prevalence of chronic medical condi tions.(1) However, taking several drugs together substantially increas es the risk of drug interactions, unwanted effects, and adverse reacti ons. Many medications need to be used with special caution because of age-related changes in pharmacokinetics and pharmacodynamics.(2) For s ome drugs, an increase in the volume of distribution (eg, diazepam) or a reduction in drug clearance (eg, digoxin) may lead to higher plasma concentrations in older than in younger patients.(2) Pharmacodynamic changes with ageing may result in an increased sensitivity to the effe cts of certain drugs (eg, opioids) for any given plasma concentration. (3) While a physician can usually do little to alter the characteristi cs of individual older patients to affect the kinetics or dynamics of drugs, the decision whether to prescribe anything at all, the choice o f drug, and the manner in which it is to be used (eg, dose and duratio n of therapy) are all factors that are under control of the prescriber . Patient adherence to the regimen prescribed is important, and there should be a partnership between physician and patient in therapeutic d ecision making. We will discuss here mays of improving prescribing for older patients. Specifically, we will examine the scarcity of informa tion to guide prescribing decisions, the general principles of prudent prescribing, and the opportunities to clarify and expand knowledge ab out drug therapy in the elderly.