Polypharmacy, defined as concurrent use of several drugs, is not uncommon in the elderly and increases their risk of adverse drug reactions and interactions. Besides adverse drug reactions and drug-drug interactions, other clinical sequelae of polypharmacy include nonadherence, increased risk of hospitalizations, and medication errors.
Although polypharmacy can be an issue in any age group, it can especially be a problem for the elderly, who consume more medications than any other patient group. It has been reported that the number of drugs prescribed for patients increases as they age. This is likely due to the increased number of chronic diseases prevalent in this population. It has been estimated that 78% of patients older than 65 years are on medications, and that 39% regularly take five or more drugs. Up to 90% of the patients in this age group are also reported to take over-the-counter drugs. As "baby boomers" age and as new medications become available to prevent and treat medical conditions such as cancer, polypharmacy and its risks will grow.
Cancer and Aging
The connection between aging and cancer is significant, with more than 60% of all cancers occurring among those over age 65. As the aging population increases and more people move into this high risk group—projected at 20% of our population (or 1 in 5 Americans) by the year 2030—there will be an increasing burden of cancer in the elderly and more demands will be placed on the medical and research establishment to respond to this burden. Older-aged Americans are an important target population for cancer research and cancer control.
The complexities of medical management in aging patients with cancer and comorbidities, availability of nonprescription medications, tendency to self-treat, and the prohibitive costs of some anticancer medications can all contribute to the increased potential for polypharmacy, and ultimately may affect treatment tolerance and outcomes. Despite concerns about polypharmacy, however, few data characterizing the extent of drug use in older patients with cancer exist.
Factors Contributing to Polypharmacy
Older patients with cancer are especially vulnerable to various factors that may contribute to polypharmacy in this population. Medical advances have greatly increased the number of medications available to treat a variety of conditions. As older patients are more likely to have several chronic conditions, this can lead to care by more than one health-care provider, each of whom may prescribe a different medication to treat the same symptom.
Data have shown that 31% of individuals aged 65 and older use more than one pharmacy to fill prescription medications. This creates a situation where each pharmacy checks for potential problems only on those medications that its pharmacist knows the patient is (or is supposed to be) taking.
1. Rollason V, Vogt N: Reduction of polypharmacy in the elderly: A systematic review of the role of the pharmacist. Drugs Aging 20:817-832, 2003.
2. Azad N, Tierney M, Victor G, et al: Adverse drug events in the elderly population admitted to a tertiary care hospital. J Healthc Manag 47:295-305, 2002.
3. Jorgensen T, Johansson S, Kennerfalk A, et al: Prescription drug use, diagnoses, and healthcare utilization among the elderly. Ann Pharmacother 35:1004-1009, 2001.
4. Hanlon JT, Fillenbaum GG, Ruby C, et al: Epidemiology of over-the-counter drug use in community dwelling elderly: United States perspective. Drugs Aging 18:123-131, 2001.
5. Yancik R, Ries LA: Aging and cancer in America: Demographic and epidemiologic perspectives. Hematol Oncol Clin North Am 14:17-24, 2000.
6. Sokol KC, Knudsen JF, Li MM: Polypharmacy in older oncology patients and the need for an interdisciplinary approach to side-effect management. J Clin Pharm Therap 32:169-175, 2007.
7. Hume AL: Safe and effective drug therapy in older adults. Med Health R I 88:15-17, 2005.
8. Stern M: Case studies in geriatric emergencies: Polypharmacy. Emerg Med 39:10, 2007.
9. Nahin RL, Fitzpatrick AL, Williamson JD, et al: Use of herbal medicine and other dietary supplements in community-dwelling older people: Baseline data from the Ginkgo Evaluation of Memory Study. J Am Geriatr Soc 54:1725-1735, 2006.
10. Patel KB, Klepser ME, Marangos MN, et al: Drug interactions in the elderly: The role of polypharmacy. Phila Coll Pharm Sci Apr:19S-26S, 1994.
11. Schainen JS, Burggraf V: Screening for polypharmacy in a nursing home care unit, in Burggraf V, Barry R (eds): Gerontological Nursing: Current Practice and Research, pp 189-193. Thorofare, NJ; Slack; 1996.
12. Corcoran ME: Polypharmacy in the older patient with cancer. Cancer Control 4:419-428, 1997.
13. Wallace K, Cantor A, Overcash J, et al: Influence of concomitant medications on toxicity from chemotherapy in elderly patients: Focus on cytochrome P-450 inhibition and protein binding effects (abstract 8025). J Clin Oncol 23(16S):735s, 2005.
14. Nies AS, Shand DG, Wilkinson GR: Altered hepatic blood flow and drug disposition. Clinical Pharmacokinetics 1:135-155, 1976.
15. Wood AJ, Feely J: Pharmacokinetic drug interactions with propranolol. Clinical Pharmacokinetics 8:253-262, 1983.
16. Mathijssen RHJ, Verweij J, de Bruijn P, et al: Effects of St. John's wort on irinotecan metabolism. JNCI Cancer Spectrum 94:1247-1249, 2002.
17. Mansky PJ, Straus SE: St John's wort: More implications for cancer patients. JNCI Cancer Spectrum 94:1187-1188, 2002.
18. Spina E, Scordo MG: Clinically significant drug interactions with antidepressants in the elderly. Drugs Aging 19:299-320, 2002.
19. Gebhardt MW, Governali JF, Hart EJ: Drug related behavior, knowledge and misconceptions among a selected group of senior citizens. J Drug Educ 8:85-92, 1978.
20. Zhan C, Arispe I, Kelley E, et al: Ambulatory care visits for treating adverse drug effects in the United States, 1995-2001. Joint Commission Journal on Quality of Patient Safety 31:372-378, 2005.
21. Perry DP: When medicine hurts instead of helps. Consultant Pharmacist 14:1326-1330, 1999.
22. Bootman JL, Harrison DL, Cox E: The health care cost of drug-related morbidity and mortality in nursing facilities. Arch Intern Med 157:2089-2096, 1997.
23. Scharlach AE, Mor-Barak ME, Katz A, et al: Genration: A corporate-sponsored retiree health care program. Gerontologist 32:265-269, 1992.
24. Colt HG, Shapiro AP: Drug induced illness as a cause for admission to a community hospital. J Am Geriatr Soc 37:323-326, 1989.
25. Beers MH: Explicit criteria for determining potentially inappropriate medications use by the elderly, an update. Arch Intern Med 157:1531-1536, 1997.