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It is well known that the potential for drug-drug interactions always is a possible consequence of drug therapy. Moreover, as the geriatric population in the United States continues to rise, so does the incidence of polypharmacy. Individuals 65 years and older make up > 13% of the population, but they consume ~30% of all prescription medications. Older individuals account for > $3 billion in annual prescription drug sales. Also, 61% of this specific patient population is taking ?? 1 prescription drugs, and most take an average of 3 to 5 medications.1 Nearly 46% of all elderly individuals admitted to hospitals in the United States may be taking ?? 7 medications.2
Whereas appropriate drug therapy often is necessary in the maintenance and prevention of disease states, excessive use of medications can result in adverse reactions. Use of multiple medications is particularly prevalent among the elderly population, leading to complex drug regimens and the risk of further complications.
Polypharmacy typically is defined as the concurrent use of ?? 5 drugs by the same patient. Polypharmacy, however, is more complex than just the number of drugs that a patient takes. Clinically, the criteria utilized for identifying polypharmacy involve the following:
The problems that may be associated with polypharmacy can be so extensive that it was designated as the principal medication safety issue in the Department of Health and Human Services report Healthy People 2000.3-5
Polypharmacy increases the possibility of drug-drug and drug-disease interactions. The elderly population is at greater risk because of normal physiologic changes that occur with the aging process. These physiologic changes, particularly decreased renal and hepatic function, in turn may contribute to changes in pharmacodynamics and in the pharmacokinetics process.
Types of Polypharmacy
Polypharmacy more commonly has a negative connotation, but sometimes it is necessary and can be beneficial in treating certain medical conditions. Polypharmacy can be categorized into 2 major classes.4
This type occurs when multiple drug regimens are carefully monitored by clinicians and are necessary for the treatment of conditions and for achieving a therapeutic goal. An example of therapeutic polypharmacy is the combination therapy of isoniazid, rifampin, ethambutol, pyrazinamide, and pyridoxine in the initial treatment of tuberculosis.4 Another example of therapeutic polypharmacy is the multiple agents used in the management of congestive heart failure, such as digoxin, angiotensin-converting enzyme inhibitors, and a diuretic.
This type of polypharmacy occurs when an individual experiences unanticipated or unintentional adverse effects while he or she is on a drug regimen and is not monitored.4 Polypharmacy is particularly detrimental when an individual takes multiple pharmacologic agents for an extended period of time, particularly at high doses, without being monitored.
Various criteria markers are available for health care professionals to assess which pharmacologic agents may be considered inappropriate for utilization among the elderly population. The criteria are based on the possible risk and benefits of certain pharmacologic agents. The most commonly known criteria are the Beers Criteria. This list was developed by Mark H. Beers, MD, in 1991 and was revised in 1997 to include medications that should be avoided (disease-independent or because of a patient's preexisting medical condition).6
Polypharmacy and Adverse Drug Reactions
The major concern for all cases of polypharmacy is the prospect of adverse drug reactions and serious drug-drug interactions. In some instances, it is therapeutically necessary to use multiple agents to treat certain conditions. It is the responsibility of pharmacists to assess patients with multiple medication regimens and to make recommendations when necessary.
Researchers have shown that more than 75% of adverse drug reactions that result in hospitalization are related to known pharmacologic agents and are partly due to inadequate monitoring, inappropriate prescribing, and lack of patient education and compliance.7 Research also suggests that the potential for an adverse drug reaction to occur is 6% when an individual takes 2 medications. It increases to 50% when 5 medications are taken concomitantly, and it rises to 100% when ?? 8 medications are prescribed.3
Screening in cases of polypharmacy, particularly in the elderly patient population, is crucial because adverse drug events can often imitate other geriatric syndromes or precipitate confusion, falls, incontinence, urinary retention, and malaise. These side effects in turn may cause a physician to prescribe another agent to treat them.1
The Role of the Pharmacist in Polypharmacy Management
Jay L. Schwab, RPh, BCNSP, a clinical pharmacist practicing in Louisiana and specializing in adult medicine, surgery, nutrition, and critical care, has stated that pharmacists can aid in the reduction or avoidance of polypharmacy in the following ways:
Some of the most common pharmacologic agents that are associated with adverse effects are nonsteroidal anti-inflammatory drugs, psychotropics, antihypertensives, and antibiotics. One important step is to review and assess the specific indications for certain medications.
As stated above, it is very common, particularly in the elderly, to see medications prescribed to treat side effects of other medications. Pharmacists can make recommendations to discontinue those medications and prescribe alternative therapeutic choices. As clinicians, pharmacists can play a fundamental role in identifying those agents that may not be necessary in a patient's drug regimen. They also may be able to suggest nonpharmacologic therapies to meet a patient's particular needs.
Although the solution may not be a simple one, in most cases polypharmacy can be managed through a multidisciplinary approach. The objectives of appropriate pharmacologic therapy are to treat or manage disease states, to prevent complications associated with comorbidities, and to ease or eradicate pain. The achievement of these goals can be obtained through precise and routine drug monitoring. Therefore, the ultimate challenge for all health care professionals is to ascertain the most suitable drug therapy for each patient that will enhance that patient's quality of life without compromising the patient's ability to function and put him or her at risk for adverse reactions.
Whereas some degree of adverse effects may be unavoidable, their severity or incidence can be significantly reduced through pharmacist intervention and through educating patients. The elderly population can obtain the benefits of pharmacologic therapy even when a drug regimen is a complex one, if drug regimens are tailored to meet the specific needs of each individual patient. It is important to note that Healthy People 2010, a national initiative to improve the health of all Americans, is planning to ensure regular review of medications used by the elderly population.6
Ms. Terrie is a clinical pharmacy writer based in Slidell, La.
For a list of references, send a stamped, self-addressed envelope to: References Department, Attn. A. Stahl, Pharmacy Times, 241 Forsgate Drive, Jamesburg, NJ 08831; or send an e-mail request to: firstname.lastname@example.org.
For more information on Healthy People 2010, visit the National Institutes of Health Web site: www.nih.gov. More information on the Beers Criteria can be found at the American Society of Consultant Pharmacists Web site: www.ascp.com.