Adverse drug reactions in elders: looking for flubs in all the wrong places

A great deal of energy – and money – has been spent on preventing adverse drug reactions in elders. Many of these efforts have had limited success. Taking the next step to limit the harmful impacts of adverse drug reactions (ADRs) requires a fresh approach, and should focus on monitoring adverse effects of drugs after they are prescribed rather than preventing problem drugs from being prescribed in the first place.

At first blush, this approach seems counter-intuitive – isn’t it better to prevent a problem rather than trying to catch it once it has already happened? Of course, the answer is yes, but primary prevention of ADRs is often difficult if not impossible. In large part, this is because most ADRs are not due to “bad” drugs, but are unfortunate complications of drugs that have a legitimate place in the therapeutic armamentarium. This was demonstrated in an important national studythat evaluated causes of adverse drug reactions in elders that led to emergency room visits. Less than 4% of these ADRs were attributable to drugs from the Beers criteria, a consensus list of drugs to avoid prescribing to elders. In contrast, almost one-third of all adverse events were due to warfarin and insulin, which each have clear appropriate uses in elders. In another landmark study, Gurwitz and colleaguesfound that more than half of preventable ADRs in community-dwelling elders were due to failures to appropriately monitor drugs, rather than errors at the time the drug was initially prescribed. For example, 36% of ADRs were caused by a clinician not obtaining follow-up lab tests or inquiring about drug-related side effects. Another 37% of ADRs were caused by a clinician obtaining this information but failing to make an appropriate intervention (e.g., the treating physician did not stop or lower the dose of a drug after receiving lab test results that showed drug toxicity).

A focus on monitoring isn’t perfect, since some elders are going to experience serious adverse events that cannot be reasonably anticipated or prevented. Nonetheless, there is still a lot that we can do to help older patients. Many potential ADRs can be identified before they cause clinical harm to a patient. For example, close home monitoring of blood glucose can identify patients at risk of hypoglycemic episodes before such an episode happens. Other ADRs can be identified and mitigated before they cause substantial harm (a process termed “amelioration” in the ADR literature). For example, early detection of muscle aches and elevated creatinine kinase levels in a patient taking a statin can allow a clinician to stop the drug before the symptoms progress to full-blown rhabdomyolysis.

These monitoring interventions are hardly rocket science, and often are done in clinical practice. However, the lack of systems to support monitoring programs such as these often lead to patients falling through the cracks. The energy and resources of patient safety and ADR prevention programs can be mobilized to help develop these systems. If we are really committed to reducing ADRs and promoting patient safety, targeted interventions to improve monitoring of high-risk medications and conditions are likely to yield greater benefits than the current emphasis on encouraging doctors to avoid prescribing drugs on “drugs-to-avoid” lists.