You are here
Home > Medical Calculator > Pharmacokinetic changes that occur with aging

Pharmacokinetic changes that occur with aging

Select an option below:

 

Geriatrics: Overview

There are many age-related changes that can have a significant effect on drug therapy. It is important to be aware of the complexities involved in treating this patient population in order to reduce the likelihood of an adverse event.

-Clinical Concerns-

Multiple diseases: The elderly in general have an increased incidence of chronic disease. 80% of the elderly have at least one chronic disease, and many of them have multiple diseases. This is particularly evident after age 75. The most common diseases include: arthritis, hypertension, hearing impairment, heart disease, vision impairment, orthopedic disabilities and diabetes mellitus.

Multiple medications: The elderly make up approximately 13% of the U.S. population, however, as a group they use approximately one-third of all prescriptions written each year and 40% of all over-the-counter medications used annually. On average, the elderly take approximately three times as many medications as younger patients. Thus, the elderly have ample potential for drug-related adverse events based on the number of medications alone. This is intensified by the age-related changes discussed above. It is important to use the lowest possible dose without sacrificing efficacy. Dosage reductions in many cases may help eliminate or reduce the risk of an adverse event.

Adverse drug reaction rate: The elderly experience an ADR rate that is conservatively reported to be 2-3 times that of younger adults. Most of the higher rate can be explained by changes in renal and hepatic function, and body composition associated with aging. Another important factor is the number of medications the elderly consume.

Clinically significant changes in metabolism, distribution and excretion occur in the elderly. It is vitally important to make appropriate changes in drug therapy to account for these age related changes.


References

  1. Campion EW,deLabry LO, Glynn RJ. The effect of age on serum albumin in healthy males: Report from the Normative Aging Study. J Gerontol. 1988;43:M18-M20.
  2. Feely J, Coakley D. Altered pharmacodynamics in the elderly. Clin Geriatric Med. 1990; 6:269-283.
  3. Greenblatt DJ, Sellers EM, Koch-Weser J. Importance of protein binding for the interpretation of serum or plama drug concentrations. J Clin Pharmacol. 1982;22:259-263.
  4. Hammarlund ER, Ostrom JR, Kethley AJ. The effects of drug counseling and other educational strategies on drug utilization in the elderly. Med Care. 1985;23:165-170.
  5. Frontera WR, Hughes VA, Lutz KJ, Evans WJ. A cross-sectional study of muscle strength and mass in 45- to 78-year-old men and women. J Appl Physiol. 1991;71:644-650.
  6. Hanlon JT, Schmader KE, Koronkowski Mj, et al. Adverse drug events in high risk older patients. J Am Geriatr Soc. 1997; 45(8):945-8.
  7. Lamy PP. Physiological changes due to age: pharmacodynamic changes of drug action and implications of therapy. Drugs Aging. 1991;1:385-404.
  8. Levy RA. Therapeutic inequivalence of pharmaceutical alternates. Amer Pharm. 1985; April: 28-39.
  9. MacLennan WJ, Martin P, Mason BJ. Protein intake and serum albumin levels in the elderly. Gerontology. 1977;23:360-367.
  10. Schmucker DL. Aging and drug disposition: An update. Pharmacol Rev. 1985;37:133-148.
  11. Thoreson J. Drug Metabolism and Drug/Drug Interactions from a Geriatrics Perspective. Clin Ger. 1997; 5: 57-74.
  12. Tregaskis BF, Stevenson IH. Pharmacokinetics in old age. Br Med Bulletin. 1990; 46: 9-21.
  13. Wilcox SM, Himmelstein, Inappropriate drug prescribing for the community-dwelling elderly. JAMA. 1994; 272:292-296




Pharmacokinetic changes that occur with aging

thpxl