DOI: https://doi.org/10.36347/sjmcr.2026.v14i01.004

Pages: 15-18

Remimazolam is an ultra–short-acting benzodiazepine increasingly used for anesthetic induction because of its rapid onset and favorable hemodynamic profile. Although generally considered safe, reports of severe hypersensitivity reactions, including anaphylaxis, remain rare, and the underlying mechanisms are not fully elucidated. We describe a case of a 68-year-old man (ASA physical status III) scheduled for therapeutic laryngomicroscopic laser surgery who developed life-threatening anaphylaxis immediately after remimazolam induction. Within minutes of intravenous administration of 14 mg of remimazolam, the patient developed severe bronchospasm refractory to rocuronium, profound hypotension, and transient atrioventricular block, consistent with features of Kounis syndrome. Oxygen saturation and blood pressure became undetectable, indicating acute respiratory and circulatory collapse. Prompt administration of intravenous epinephrine (0.1 mg bolus followed by continuous infusion) resulted in rapid hemodynamic recovery. The patient had undergone uneventful general anesthesia with propofol and other agents 10 months earlier, strongly implicating remimazolam as the causative agent. Arterial blood gas analysis revealed no significant abnormalities after stabilization. Surgery was completed successfully, and the patient recovered without postoperative complications. Further allergy evaluation was recommended, but the patient declined additional diagnostic workup. This case highlights that remimazolam can trigger severe perioperative anaphylaxis with multisystem involvement, including rare cardiac manifestations suggestive of Kounis syndrome. Prior tolerance to other anesthetic agents does not preclude hypersensitivity reactions to remimazolam. Early recognition, differentiation from other intraoperative complications, and prompt administration of epinephrine are critical for successful management. As the clinical use of remimazolam expands, increased awareness and systemati