Module232025

07/05/2025

The elderly – AD & E changes

Absorption, distribution and excretion change as we age – all can affect pharmacokinetics and impact dosing recommendations slowed gastric emptying  delayed Cmax, increased absorption reduced gastric acidity  changed absorption decreased plasma proteins, increased fat percentage, decreased lean tissue mass  increased [C] plasma for hydrophilic drugs reduced elimination of lipophilic drugs

reduced cardiac output  decreased rate of distribution reduced GFR and renal secretion  decreased clearance

For a more detailed review, see Ref #4

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The elderly - hepatic metabolic changes

• With aging, the liver’s capacity for metabolism through the CYP450 enzyme system is reduced by ≥30% because hepatic volume and blood flow are decreased higher levels and prolonged half-lives • Aging does not affect glucuronidation. • First-pass metabolism (metabolism that occurs before a drug reaches systemic circulation) decreases by about 1%/year after age 40. Greater systemic exposure

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