Abstract
Ondansetron, a drug predominantly employed in most general anesthesia cases, is critical for mitigating postoperative nausea and vomiting prompted by anesthetics. Although infrequent side effects such as serotonin syndrome are recognized, the drug is generally acknowledged for its safety. Nonetheless, some reports showed cases of anaphylactic shock associated with ondansetron. In this context, we have meticulously analyzed an anaphylactic case triggered by ondansetron that we encountered. Our deep-dive investigation suggests that the reaction might not be a traditional type I allergic reaction, typically associated with the drug. Instead, we present the possibility that the response could be mediated through Mas-related G protein-coupled receptor X2 (MRGPRX2), a divergent pathway leading to comparatively milder symptoms of anaphylaxis. In addition to the crucial role of adrenaline in unstable hemodynamics, our case highlights the effective use of antihistamines in rapidly managing such reactions. This finding suggests a need to further examine the safety profiles of common drugs like ondansetron and the potential involvement of MRGPRX2 in drug-induced hypersensitivity reactions.