Medication-related errors jeopardize patient safety and commonly result in otherwise unnecessary hospitalizations. Approximately 7% of hospital admissions result from drug-related errors, of which 59% are considered preventable.1 It is estimated that adverse drug events affect 2% to 5% of hospitalized patients.2,3 These errors result in increased hospital costs of $4,700 per admission, or about $2 billion annually for U.S. hospitals.2 Calculations indicate that in the nursing home, for each dollar spent on a medication, there is another $1.33 spent on healthcare resources for the treatment of a drug-related morbidity or mortality.
Unfortunately, older folks are particularly susceptible to medication-related problems. Age-associated changes in body composition and physiology, multiple comorbidities, and—last but not least—polypharmacy, are contributing factors. In the United States, patients older than 65 fill an average of 12 prescriptions per year, compared with five fills for patients between ages 25 and 40. In addition, the use of nonprescription medications is more common in the elderly. This opens up the possibility of increased drug-drug or drug-herbal interactions.
Depending on the healthcare setting, as well as the criteria that define inappropriate medication use, studies alert us that between 7% and 21% of ambulatory older folks receive at least one potentially inappropriate medication.4,5 About 60% of nursing home residents, and a staggering 92% of frail elderly hospitalized veterans, receive at least one potentially inappropriate medication.6,7 The consequences of inappropriate drug use in the elderly can be significant. Weakness, resulting in loss of independence and falls that end in bone fractures, is only one possible negative consequence. Between 10% and 20% of the elderly are hospitalized as a result of receiving these inappropriate medications.8,9
Screening Inappropriate Medication
So, what are inappropriate medications for the elderly? Overly simplified, they include any medication that has a greater potential for doing more harm than good. In 1991, Beers and colleagues published criteria for screening inappropriate medication use in elderly patients.10 The authors reviewed the literature and identified 14 nationally recognized authorities in the fields of geriatric pharmacology, epidemiology, geriatrics, and long-term care. Among these experts, consensus was reached on a list of inappropriate medications for elderly nursing home residents. The list was intended to identify medications that should be avoided except under unusual circumstances. The experts also developed criteria for optimal doses, frequencies, and duration of use for these medications.
Since 1991, the criteria have been updated twice (in 1997 and 2002) to include ambulatory elderly. The 2002 Beers list included 48 inappropriate drugs or medication classes, regardless of diagnosis or conditions.11 Because drug-disease interactions in the elderly are increasingly recognized, the 2003 Beers list also included inappropriate medications or medication classes for 20 medical conditions. The consensus panel of experts identified 66 inappropriate drugs with adverse outcomes of potentially high severity. The authors stated specifically that the criteria were not meant to regulate practice to the point at which they would supersede the clinical judgment and assessment of the medical practitioner.
Based on Beers’ criteria for inappropriate prescribing, a literature review of studies conducted between 1992 and 1999 found that between 14% and 23% of the elderly filled a prescription for one or more drugs on the Beers list.12 Long-acting benzodiazepines, dipyridamole, propoxyphene, and amitriptyline were among the most frequently prescribed inappropriate medications.
Cardiovascular and psychotropic drugs are most commonly involved in drug-drug interactions. The most common adverse effects are acute renal failure, hypotension, and neuropsychological presentations such as delirium. Risk factors predisposing to adverse reactions are using multiple medications, receiving care from several prescribing clinicians, and filling prescriptions at more than one pharmacy. Physicians should also be vigilant for drug-herbal interactions.