Prehospital stability of diazepam and lorazepam

Injectable benzodiazepines are commonly stocked on ambulances for use by pa ramedics, We evaluated the stability of lorazepam and diazepam as a functio n of storage temperature, Diazepam (5 mg/mL) and lorazepam (2 mg/mL) inject able solutions were stored for up to 210 days in clear glass syringes at th ree conditions: 4 degrees C to 10 degrees C (refrigerated); 15 degrees C to 30 degrees C (on ambulance ambient temperature); and 37 degrees C (oven-he ated), High performance liquid chromatography (HPLC) analyses of syringe co ntents were performed at 30-day intervals, After 210 days, the reduction in diazepam concentration was 7% refrigerated, 15% at ambient temperature, an d 25% at 37 degrees C, The reduction in lorazepam concentration was 0% refr igerated, 10% at ambient temperature, and 75% at 37 degrees C, Whereas diaz epam retained 90% of its original concentration for 30 days of on ambulance storage, lorazepam retained 90% of its original concentration for 150 days . The decrease in lorazepam concentration correlated with an increase in th e maximum ambient temperature in San Francisco. These results suggest that diazepam and lorazepam can be stored on ambulances, When ambient storage te mperatures are 30 degrees C or less, ambulances carrying lorazepam and diaz epam should be restocked every 30 to 60 days. When drug storage temperature s exceed 30 degrees C, more frequent stocking or refrigeration is required. Copyright (C) 1999 by W.B. Saunders Company.