Impact of Ambient Temperature on 5 Emergency Drugs Aboard an Emergency Medical Car Over a 1-Year Period

Study objective: Drugs in emergency medical service (EMS) cars are often exposed to temperature variations that could affect the stability of these drugs. We aimed to study the influence of real-life temperature exposure on the stability of 5 drugs onboard an EMS vehicle.

Methods: Concentrations of active principles of 5 emergency drugs (amiodarone, rocuronium, fentanyl, succinylcholine, and epinephrine) aboard an EMS vehicle were analyzed every 3 months up to 1 year. The samples were compared to the same drugs stored for 1 year either at room temperature or in a refrigerator in the pharmacy. Succinylcholine was additionally analyzed once a week for 4 weeks after being taken out of the refrigerator. The dosage of the active principle was measured using high-pressure liquid chromatography coupled with ultraviolet detection.

Results: After the 12-month period, all drugs from the EMS car, except succinylcholine, presented concentrations still above 90% of the concentrations measured at the start of the project. Concentrations ranged from 96.3% to 103%. For succinylcholine at 12 months, the remaining concentration was 89%. Temperatures in the EMS car ranged from 13.9 °C to 33.9 °C (median, 22.8 °C [interquartile range, 20.5 °C to 25.8 °C]).

Conclusion: In real-life conditions, amiodarone, rocuronium, fentanyl, succinylcholine, and epinephrine onboard an EMS vehicle did not suffer pharmacologically relevant degradation from temperature variations. All concentrations measured remained in the specification intervals given by the manufacturers.