To evaluate the drug constitution of dantrolene by comparing reconstitution with diluent at ambient and warmed temperatures, so as to determine whether differences in reconstitution time might provide clinical or therapeutic advantages.

Randomized study.

University-affiliated medical center.

We reconstituted 10 vials of dantrolene, 5 with room-temperature diluent (sterile water) and 5 with diluent warmed to approximately 41°C. Injection of diluent (10 seconds) was followed by 5 seconds of observation and recurring 15-second cycles (10 seconds of moderate manual agitation followed by 5 seconds of observation) until full reconstitution. In a second series of reconstitutions, warmed diluent injection was immediately followed by predetermined lengths of moderate manual agitation, and reconstitution status was noted at the end of each trial. Time to full reconstitution was based on a series of predetermined objective criteria. In experiment 1, with ambient-temperature diluent (22.0°C -23.1°C), reconstitution occurred in 90 to 130 seconds; whereas warmed diluent (40.7°C-41.3°C) reconstitution occurred in less than 30 seconds (P < 0.004). In experiment 2, with warmed diluent (40.9°C), full reconstitution occurred after 10 seconds of injection and 18 seconds of moderate manual agitation.

The use of prewarmed diluent to 41°C significantly reduces dantrolene reconstitution time. Further studies should evaluate the efficacy of dantrolene reconstituted with warmed diluent.