The elderly—a challenge for appropriate drug treatment

Abstract

The current rise in life expectancy in the industrial world has made aging a “hot” topic in life sciences and public health. Major contributing factors to this success are improved hygiene practices, a sharp fall in infant mortality and the development of beneficial drugs [1]. In general, there is an increase in drug consumption with age because elderly subjects often suffer from multiple (chronic) disease states and organ dysfunctions [2]. In addition, in keeping with the above statement of J. Swift, there is presently considerable “hype” on antiaging medicine. However, as pointed out by an expert panel there is no evidence that there is any remedy which can slow aging or increase longevity in humans [3]. Thus, there is no need to discuss anti-aging compounds which only will help the distributors but not the consumers. In contrast, we have to remember that many effective drugs have contributed to our extended life expectancy by curing diseases, improving pathophysiological conditions and increasing the quality of life. When talking about such positive drug actions one should also consider that the elderly patients, as defined by the WHO as those with an age above 65 years, might differ in their drug response when compared to younger subjects [4]. When considering drug consumption in 70-year-old Scandinavian populations between 1971 and 2000 there was a 12–19% increase in the proportion of subjects using drugs during that period. At 79–80 years, the mean number of drugs was 3.3 in men and 4.0 in women in 1980 and 4.0 in men and 4.7 in women in 1995 [5]. Thus, problems associated with polypharmacy have apparently been increasing in recent years. They primarily consist of adverse drug reactions (ADR), which are more often observed in the elderly [6], and drug interactions which occur frequently in this population. [7]. As most of these drug-related problems are dose-dependent, pharmacological knowledge and skills are needed to find the right dosage for elderly patients. The prescribing physician should be aware that age-related changes in pharmacokinetics (PK) and pharmacodynamics (PD) will occur with several drugs and these often need to be considered for an adjusted dosing regimen. There might be age-related up or down regulations of targets (receptors), transmitters or signalling pathways which can modify the action of drugs. Body composition changes with advancing age (relative lipid content increases; total body water and lean body mass decreases) which can affect drug distribution and often will result in drug retention and prolonged t1/2. Kidney function will decline in old age, but in the absence of diseases, it does not decrease as greatly as previously accepted. Likewise, hepatic function seems to be quite well preserved in the fit elderly [4, 7, 8]. Consequently, drug elimination in the elderly is only slightly reduced if at all. When considering the impact of old age on the action of drugs one has to differentiate the group of fit elderly from that of frail elderly which represent a subgroup of patients in whom it is not aging per se but multiple disease states that Eur J Clin Pharmacol (2008) 64:225–226 DOI 10.1007/s00228-007-0410-5