Diphenhydramine overdose: a review of prevalence, presenting symptoms, and the pressing need to develop and implement a prompt toxicology screen
Abstract
Diphenhydramine (DPH) is a popular antihistamine found in many over-the-counter allergy, sleep, nausea, and cough remedies. Naturally, such a wide range of OTC medications containing DPH––which are often coingested––make unintentional DPH overdoses an inevitability. In 2016 and 2017, DPH was also recognized as one of the drugs most widely implicated in suicide attempts within the US. Recent viral social media trends further promote treacherous misuse of DPH to achieve hallucinogenic effects. Despite such prevalence of acute diphenhydramine poisoning (DPHP), most emergency departments and hospitals do not include DPH in routine diagnostic toxicology screens and lack standardized symptomatology listing DPHP as a differential diagnosis. In this literature review, clinical case studies and epidemiologic studies involving emergency or inpatient treatments of DPHP without coingestion were analyzed for presenting symptoms and subsequent medical decision making. Findings most commonly equated DPHP to anticholinergic poisoning symptoms––emphasizing the prevalence of confusion, agitation, sedation, altered mental status, and coma in DPHP. Such symptoms render patients unable to self-report DPH intake and further highlight the urgent need for routine DPH toxicology screens. Besides anticholinergic poisoning, DPHP was also described as occasionally “mimicking” serotonin syndrome (SS). Other notable findings were, in order of frequency, secondary status epilepticus, CNS depression, wide-complex tachycardia, and QT interval prolongation. Because presenting symptomatology can range so widely, this review's findings support the development and incorporation of routine and rapid diagnostic toxicology screenings for DPH. Such screenings will streamline medical decision making for patients experiencing the aforementioned symptoms.
About the Presenter
Anastasiya Kozlovska
Anastasiya Kozlovska is a fourth-year neuroscience undergraduate. As a pre-medical student, she believes that effective healthcare is the product of several finely intertwined strings working together. These strings can simultaneously impact individual health outcomes and an entire community’s healthcare system. Some strings that she explores are public health and health psychology––and, of course, the neuroscience underlying both. For over two years, she collaborated on research projects that integrate these elements to promote evidence-based practice and advocate informed healthcare policies.