Cognitive and Other Adverse Effects of Diphenhydramine Use in Hospitalized Older Patients

Abstract

ADVERSE DRUG reactions are a common iatrogenic complication in older hospitalized patients.¹ Polypharmacy exacerbates the problem,² as do inappropriate prescribing patterns,³ enhanced sensitivity to adverse effects due to age-related changes in pharmacodynamics and pharmacokinetics,^4,5 and interactions among multiple, often new, medications. An important drug-related iatrogenic outcome in the elderly is cognitive impairment.^6,7 Drug-related cognitive impairment and delirium are particularly important in the inpatient setting, which represents an already vulnerable time because of the superimposition of acute illness and multiple drug use onto existent cognitive and medical comorbidities. In fact, the addition of a multiple-medication regimen during a hospital stay is an independent risk factor for delirium in older hospitalized patients.⁸