Prophylactic antibiotics and neuromuscular blocking agents (NMBA) are two of the major causative agents of anaphylaxis after induction of anesthesia. One female and one male patients (aged 29 and 69 years, respectively) had Ring and Messmer scale grade III anaphylaxis after administration of prophylactic antibiotics following induction of anesthesia. They showed typical hemodynamic and respiratory features of life-threatening anaphylaxis. Postoperative skin tests in these two patients were

more »

... ive for antibiotics and concurrently positive for rocuronium. Our present report suggests the possibility that both prophylactic antibiotics and NMBA concurrently and synergistically enhance anaphylactic reaction and the necessity to differentiate an immune mechanism from non-immune mechanisms when anesthesiologists encounter concurrent positive skin tests for both antibiotics and NMBA.