A case series of hyperthermia crisis in cough mixture ingestion: Why early cooling save lives.

Objective: Hyperthermia (core body temperature >40°C) associated with cough mixture ingestion has been reported in case studies. However, clinical data and consensus on treatment remain limited. This study aimed to identify associated factors, characterize clinical manifestations, and evaluate management approaches for hyperthermia following cough mixture ingestion. Methods: A territory-wide retrospective case series was conducted using data from the Hong Kong Poison Information Centre (HKPIC) between 1 January 2013 and 31 December 2023. Patients aged > 18 years with cough mixture ingestion, hyperthermia (>40°C), and urine toxicology results were included. Cases with abusive stimulant co-ingestion were excluded. Results: Of 434 recorded cough mixture exposures, 156 had urine toxicology results. After exclusions, 9 patients were included (100 % male; median age 37.1 ± 9.0 years). Mortality was 33.3 % (3/9). All cases occurred in daytime with ambient temperatures > 36°C. Promethazine and ephedrine were detected in all patients. Cooling methods were used in 55.6 % (5/9). Conclusion: Promethazine/ ephedrine containing cough mixtures and high ambient temperatures may synergistically contribute to hyperthermia. Early recognition and aggressive cooling are critical to reduce mortality. Such cough mixtures should be restricted from being sold as over-the-counter medications.