Safe Prescribing: Interdisciplinary Solutions
by Mark Monane, M.D., and Lisa A. Cataldi, M.P.H.

Despite the widespread use of prescription drugs by the aged population, prescribing for the elderly may be less than optimal. Factors such as patient age, multiple diseases and disease severity, use of multiple medications, and physicians' lack of training in geriatrics contribute to placing elderly individuals at increased risk of developing adverse drug events (ADEs).
ADEs are defined as noxious and unintended patient events: symptoms, signs or laboratory abnormalities caused by a drug (Naranjo et al., 1992). They may result in significant morbidity, mortality and cost (Bates et al., 1997). Better understanding of the challenges associated with prescribing for the elderly will allow clinicians to develop and implement strategies for optimal prescribing.

Age-Related Changes
The incidence of ADEs in the community-dwelling elderly varies widely from 5% to as much as 35% (Hanlon et al., 1997), with differences attributed to various methods used to ascertain these events (Hanlon et al., 1994).
Interestingly, as a result of underreporting and mistakenly attributing symptoms to medical conditions or the aging process overall, the prevalence of ADEs in the elderly may be underestimated (Chrischilles et al., 1992).
Common physiologic changes that accompany the aging process often alter the pharmacokinetic and pharmacodynamic properties of many drugs (Golden et al., 1999; Lindley et al., 1992). As a result, the processes of drug absorption, distribution, metabolism and excretion may sometimes be disrupted (Committee on Pharmacokinetics and Drug Interaction in the Elderly, 1997), resulting in a complication.

Multiple Diseases
Multiple disorders and severity of each disease also may contribute to the increased likelihood for ADEs in the elderly. For example, the concordance of osteoarthritis and congestive heart failure-two common disorders in the ambulatory elderly population-can lead to the prescription of both a nonsteroidal anti-inflammatory class of pain medications and a diuretic for fluid-overload management. The combination of these two necessary medications is a precursor for an ADE-especially when two treating physicians independently prescribe for the same patient.
In addition, the numerous other medications needed to treat these conditions are associated with a higher incidence of ADEs in the elderly (Grymonpre et al., 1988; Hallas et al., 1990; Hutchinson et al., 1986).
ADE risk increases with each additional medication prescribed (Hanlon et al., 1997). The paradox, however, is that the multiple use of medications, or polypharmacy, for disease management in a given elderly patient can be a desirable situation.
Yet, polypharmacy with duplicative or interacting medications should be avoided. In fact, elderly people living in the community take an average of 4.5 medications per day (Schwartz, 1997), and institutionalized elders average eight prescriptions each day (Ferrini and Ferrini, 1993).

Lack of Geriatric Expertise
Compounding these challenges is a general lack of geriatric training in both medical and pharmacy education (General Accounting Office, 1995). Sixty-eight percent of visits by elderly people to office-based physicians are associated with initiation or continuation of a prescribed medication (Woodwell, 1999). Many of these physicians may not have received geriatric training, thereby increasing the risk of suboptimal prescribing for their elderly patients. Without appropriate training in geriatric pharmacology, physicians may be unaware that some medications are particularly prone to ADEs (Monane et al., 1998a).

Below-Optimal Prescribing
In a 1991 study, investigators from the department of medicine at the University of California, Los Angeles used a Delphi survey method to develop 30 criteria sets to identify potentially inappropriate medications in elderly nursing home patients (Beers et al., 1991). Their recommendation focused on drugs that should be avoided, excessive dosing and excessive duration of treatment in 15 common medical conditions.
In 1997, Beers published an updated recommendation that identifies 28 criteria for suboptimal prescribing in elderly outpatients. Wilcox et al. (1994) applied these criteria to 6,171 non-institutionalized elderly from the 1987 National Medical Expenditure Survey. The researchers concluded that nearly one-fourth of all elderly people living in the community were prescribed an inappropriate medication.
More recently, Golden et al. (1999) found that nearly 40% of 2,193 homebound elderly individuals were prescribed an inappropriate drug according to the Beers criteria.

Finding the Solution
Clearly, there is opportunity to improve prescribing to this population. Yet, given the pervasiveness of suboptimal prescribing across the United States and the likelihood of this problem expanding as the population continues to age, finding a far-reaching solution seems quite challenging.
In 1995, Merck-Medco Managed Care, L.L.C., a large pharmacy benefit manager with 10 million elderly members, launched Partners for Healthy Aging to reduce potentially unsafe or ineffective prescriptions for the elderly. This unique program includes an educational approach combined with online computerized drug utilization review (DUR) to provide patient-specific messages to pharmacists and physicians prior to dispensing prescription medications. The initiative represents a significant step toward improving pharmacotherapy among the community-based elderly population.