Inappropriate Dosing in Elderly Emergency Department Patients

The Beer’s Criteria list identifies elderly patients’ most problematic medications.

Adverse drug reactions are the primary drivers for inclusion on the list. Examples include respiratory depression, falls, delirium, gastrointestinal (GI) bleeding, and acute kidney injury. Opioids and sedative hypnotics, including the benzodiazepines, may cause the first 3 effects and non-steroidal anti-inflammatory drugs (NSAIDs) may cause the latter 2. These reactions are possible in patients of all ages but more likely as they get older. Providers seeking to most appropriately use the listed medications should administer at the lowest dose for the shortest time possible to minimize their adverse effects.

A team of researchers from Washington State assessed the causes of age-inappropriate dosing of 3 high-risk classes in elderly emergency department (ED) patients in a new study published in the December 2017 issue of Drug, Healthcare and Patient Safety.¹

The researchers accessed medication administration records at 2 EDs to assess supertherapeutic doses of NSAIDs, opioids, and benzodiazepines. They stratified patients by magnitude of overdose, age, gender, and location.

Prescribers gave total 2.5, 1.2 “high” (1.5 to 3 times starting dose) and 0.5 “very high” (greater than 3 times starting dose) doses from the 3 classes per patient visit on average. Prescribers most frequently prescribed opioids (80% of total doses) with a much slimmer incidence of NSAID and benzodiazepine prescribing (15% and 5% respectively). The abundance of opioids is sensible; painful conditions (eg, broken bones) are leading reasons for ED visits. Women are more likely to receive benzodiazepines in the outpatient setting but less likely in this study. One explanation suggested by the study authors is that the study men were receiving benzodiazepines for alcohol withdrawal at much greater rates than women. Fentanyl, hydromorphone, and midazolam were the most commonly repeated medications in the medication administration record.

Increased age decreased the rate of supertherapeutic dosing. Patients 65 to 69 years old and older than 85 were over- and underrepresented among receivers of medications in these 3 classes. This trend reflects awareness of heightened dose sensitivity as patients grow older. Past and continuing initiatives appear to have decreased the use of these medications in the certain risk categories (older than 85 and/or a female elder). However, even 65- to 69-year-olds are particularly sensitive to supertherapeutic dosing and the associated adverse effects (eg, falls, respiratory depression, GI bleeding, and acute kidney injury).

The study authors were unable to determine whether patients had extensive tolerance to opioids and benzodiazepines. This is a critical limitation, because an “appropriate” dose is dependent on the extent of tolerance. For example, a patient with chronic cancer pain may present with an acute episode of breakthrough pain and receive a seemingly “very high” dose.

ED providers often prescribe high-risk medications at supertherapeutic doses to older patients. Indeed, these medications are inherent to the treatment of common reasons for an ED visit, but dose sensitivity increases with advanced age. The addition of a pharmacist into the ED or the incorporation of high-priority ED medicine verification may avoid the administration of inappropriately high doses. Future prescriber education, such as pharmacist-led in-services, should focus on the importance of dose moderation in younger elderly patients.

Reference

1. Kim M, Mitchell SH, Gatewood M, et al. Older adults and high-risk medication administration in the emergency department. Drug Healthc Patient Saf. 2017;9:105-112.