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.