Allergic Reaction to Ketamine as Monotherapy for Procedural Sedation

Ketamine is a cyclohexamine derivative that acts as a noncompetitive N-methyl D-aspartate receptor antagonist. Its use for procedural sedation is recommended by national clinical policy. However, its immunogenic potential is not well documented.

We report a case of allergic reaction associated with the administration of intravenous ketamine for procedural sedation in a 16-year-old male. Minutes after administration, the patient developed a morbilliform, erythematous rash that extended to the upper and lower torso and resolved with intravenous diphenhydramine. It is most likely that this allergic reaction was caused by a ketamine-induced histamine release that has been described in vitro. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: This is the first case report in which ketamine was used as monotherapy in the emergency department for the facilitation of procedural sedation that resulted in an allergic reaction. Supportive measures, including advanced airway procedures and hemodynamic support, may be necessary in more severe anaphylactic cases. Providers should be aware of this potential adverse effect when using ketamine for procedural sedation.