Patient Fall Risk Caused by Unintended Diphenhydramine Use

A 62-year-old patient living in a rural community was referred to participate in a pharmacist-led home visit program because of concerns with the patient's increasing falls and medication complexity. The patient reported experiencing an increasing number of falls over the past few months, resulting in a recent hospitalization and mild head trauma. The patient's past medical history included diabetes mellitus type 2, hypertension, hyperlipidemia, gastroesophageal reflux disease, paroxysmal atrial fibrillation, unspecified back pain, and benign prostatic hyperplasia. During the comprehensive medication review, pharmacists determined the patient had inadvertently purchased an acetaminophen/ diphenhydramine combination medication, rather than his usual acetaminophen. According to the 2019 Beers criteria, use of acetaminophen/diphenhydramine for back pain without insomnia is not the best option and may contribute to falls. With an estimated four to eight tablets per day, the patient was taking 200-400 mg of diphenhydramine daily. Pharmacist recommendations included contacting the prescribing physician to obtain a prescription for acetaminophen. By asking the local pharmacy to dispense acetaminophen as a prescription, the risk of the patient inadvertently purchasing an inappropriate product is reduced. After removing the diphenhydramine from the patient's regimen, the falls ceased. This case demonstrates the effects of inappropriate diphenhydramine use in an especially vulnerable population. It also highlights the critical role that rural community pharmacists can play in improving their patients' health care.