The lesser of two adverse reactions.

BACKGROUND

Fundamental to complex systems are interconnected processes involved in providing high-quality patient care. A case study and a root cause analysis (RCA) illustrate a patient safety effort with unintended consequences.

CASE REPORT: A 38-year-old woman presented to the hospital for odynophagia and vomiting. The patient developed Mobitz type 2, second-degree heart block temporally associated with the administration of intravenous ondansetron. RESPONSE TO THE EVENT: An Ishikawa, or fishbone, diagram conducted to enumerate potential contributing factors indicated that a key factor appeared to be an institutional restriction against using intravenous (i.v.) promethazine, which resulted in ondansetron being the only readily available i.v. anti-emetic on formulary. The anesthesia department requested that i.v. promethazine be removed from all operating and recovery room automated medication dispensing machines. The pharmacy department, given the realization that individual departments were taking independent action regarding promethazine, discussed the matter with the medical director, who issued a memo banning the use of i.v. promethazine. An institutional ban on i.v. anti-emetics such as promethazine may have resulted in an increase in the use of ondansetron and contributed to this adverse reaction. The reason to restrict promethazine is not well reported in the literature. In limiting the use of promethazine for patient safety concerns, the inadvertent increase in adverse reactions of the alternative medication, ondansetron, may have been overlooked. The resultant RCA underscores the need for careful cataloguing of adverse medication effects.

DISCUSSION: Stakeholders should anticipate as many "downstream effects" of quality and patient safety improvements as possible. Comprehensive reporting of adverse medication effects will augment the emerging science of patient safety.