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.