Off-label and unlicensed medication use and associated adverse drug events in a pediatric emergency department

The study objectives were to (1) determine the types and frequency of off-label (OL) or unlicensed (UL) medications used in a pediatric emergency department (PED) and before admission, (2) describe OL/UL-associated adverse drug events (ADEs) resulting in admission to the PED and those occurring during patient care in PED, and (3) determine the outcomes of these ADEs.

Medical records of patients 18 years or younger admitted to the PED over a 5-month period were reviewed. Off-label/UL use of medications was determined based on Food and Drug Administration-approved labeling. The Adverse Drug Reaction Probability Scale was used to determine ADE causality. Data were analyzed using descriptive statistics.

A total of 2191 patients with 6675 medication orders were evaluated. About 26.2% (n = 1712) of medication orders were considered as OL/ UL use; 70.5% (n = 1208) of these medications were ordered as part of treatment in the PED, and the remaining 29.5% (n = 504) were home medications before their PED evaluation. Inhaled bronchodilators (30.4%), antimicrobials (14.8%), and antihistamines/antiemetics (9.1%) were the most common OL/UL medication classes. The frequency of ADEs among licensed medication use was greater compared with OL/UL use by 2-fold. Reported overall rate of ADEs was 0.6% (n = 40). Of these 40 ADEs, 5 resulted from the use of an OL/UL medication, 3 from home medication use, and 2 from PED-prescribed medications.

The frequency of reported ADEs associated with OL/UL medications was less than the frequency of ADEs from licensed medication use, with overall ADE frequency of less than 1%.