Physiologic changes in old age: relation to altered drug disposition.
Current knowledge of the effects of aging on drug disposition is reviewed. Although definitive studies are not always available, based on present evidence it appears that: 1) drug absorption is not impaired in the elderly; 2) drug distribution in the elderly may be altered by significant changes in the lipid/lean body mass ratio; 3) Phase I (non-synthetic) biotransformation reactions of the liver appear to be much more profoundly affected by aging than are Phase II (synthetic) reactions; 4) age-related effects of biotransformation can be different even for compounds that are very similar and undergo the same types of reactions. Important parameters of drug metabolism are also discussed, such as the need to use total clearance, rather than half-life, in assessing pharmacokinetics.
D000368:Aged; D000375:Aging; D006801:Humans; D007408:Intestinal Absorption; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008657:Metabolic Clearance Rate; D004364:Pharmaceutical Preparations / Q000378:metabolism*; D011485:Protein Binding; D014018:Tissue Distribution
D004364:Pharmaceutical Preparations