RESUMO
BACKGROUND: Cefdinir is an extended-spectrum, third-generation, oral cephalosporin widely used in pediatric population to treat common bacterial infections, including otitis media and streptococcal pharyngitis. It is considered a safe and well-tolerated alternative to penicillin and macrolides. CASE REPORT: This report describes a case series of 3 infants presenting to the emergency department for evaluation of "bloody diarrhea." The parents noticed red stools when their children were started on oral cefdinir when they were previously receiving iron-containing preparations. Reddish-colored heme-negative stools observed in all cases were due to the interaction of the drug with supplemental iron or iron-containing formula feeds. This adverse effect was reversible on discontinuation of cefdinir. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Red stools due to cefdinir is an underreported benign adverse drug reaction with fewer than 10 cases described in the literature. Thorough history taking with an appropriate focus on diet and drug history are essential to avoid parental anxiety, unnecessary patient workup, and economic burden to the caregivers in these cases. Awareness of this unusual adverse effect among emergency physicians could prevent further inconvenience for already overburdened health systems.