Annals of Long Term Care

The majority of long-term care residents take a variety of medications on a daily basis. Nursing home residents, for example, take an average of nearly 8 regularly scheduled medications—and more than 60% take more than 9. Not surprisingly, the risk of medication-related adverse patient events is relatively high in long-term care facilities.

Because these events can cause significant morbidity among older adults, preventing and addressing them should be a top priority for long-term care. Delivering the Henderson State-of-the Art Lecture during the American Geriatrics Society’s 2007 annual scientific meeting in May, Joseph T. Hanlon, PharmD, one of the nation’s leading experts on interventions to improve drug therapy for older patients, noted that a multifaceted approach is central to reducing the incidence of adverse drug events among the elderly. Additional research, and fundamental changes in health policy, health systems, and health professional education, are essential to this effort, Dr. Hanlon noted. So, of course, is awareness of the problem and how to address it among healthcare providers, who should familiarize themselves with the different types of adverse medication events.

There are three basic types of these events, noted Dr. Hanlon, professor of Pharmacy and Geriatric Medicine at the University of Pittsburgh, and a research health scientist at the Center for Health Equity Research and Promotion with the VA Pittsburgh Healthcare System and GRECC. The three types are: adverse drug reactions, adverse drug withdrawal events, and therapeutic failure.

Adverse drug reactions are the most common. The World Health Organization (WHO) has defined adverse drug reaction as “an appreciably harmful or unpleasant reaction resulting from an intervention related to the use of a medicinal product which predicts hazard from future administration and warrants prevention or specific treatment or alternation of the dosage regimen or withdrawal of the product.” How does one identify the cause of such a reaction? While there are a dozen algorithms designed to determine how likely it is that a particular drug is the culprit, “Naranjo’s Adverse Drug Reaction Causality Algorithm” is a particularly useful one, Dr. Hanlon noted. Even so, determining causality can still be quite difficult, especially with older patients with multiple comorbidities. “There’s almost always another possible cause” with these patients,” he explained during the lecture, “so you’re almost always dealing with possibility and probability rather than definitive findings of causality.”

Studies of long-term care facility residents and home health patients have found that hospitalizations and transitions increase risks of adverse drug reactions significantly. And additional research suggests that comorbidities, polypharmacy, and the use of certain drugs, such as warfarin, are consistent risk factors for adverse drug reactions, Dr. Hanlon added. It’s prudent, then, to keep a particularly close eye on residents during and after transitions, and on residents who have multiple chronic conditions, or who take multiple medications or anticoagulants.

Therapeutic failure, the second most common but least studied type of medication-related adverse patient event, is defined as “failure to accomplish the goals of treatment resulting from inadequate or inappropriate drug therapy and not related to the natural progression of disease.” Therapeutic failure can result when a dose of a necessary drug is omitted, too low a dose is prescribed, a drug-drug interaction effectively reduces the dose of a medication, or a sub-therapeutic dose is taken for any of a variety of reasons, including patient nonadherence. In a recent study of 106 hospitalized, frail, elderly patients using a new instrument called the “Therapeutic Failure Questionnaire,” nonadherence was the leading reason for therapeutic failure, Dr. Hanlon reported.