BACKGROUND AND OBJECTIVE: Systemic reactions during anesthesia are commonly attributed to muscle relaxants, hypnotics, macromolecular solutions, latex, or parenteral antibiotics. After exclusion of these different components as causes, we were interested in the potential implication of rifamycin in the systemic reaction, which occurred during anesthesia, and in the immunologic mechanism by which it can trigger this reaction. METHODS: We report four cases of systemic reactions occurring after local administration of rifamycin. Three patients needed orthopedic surgery, and the fourth needed a urethrotomy. Severe systemic reactions occurred in all four patients when the surgeon washed the incision area with a rifamycin solution. All patients correctly responded to appropriate treatment and recovered. Skin tests were performed 2 months after the incident with the drugs used during anesthesia, latex, and rifamycin. To assess the relationship with a possible IgE-mediated mechanism, two in vitro tests were concomitantly performed to evaluate the cell reactivity to rifamycin: (1) determination of histamine release from peripheral basophils and (2) platelet cytotoxicity test, which explored the presence on platelets of specific IgE antibodies bound to the low-affinity receptor for IgE. RESULTS: Skin tests were performed with different drugs used during surgery, and results were only positive for rifamycin in the four cases, accompanied in two cases by a systemic reaction. Histamine release from basophils was positive in three of four patients. The platelet cytotoxicity test results were positive in all four cases. CONCLUSION: It appears that rifamycin, used locally during surgery, is apt to trigger severe systemic anaphylactic reactions, which are linked to an IgE-related process. This situation is worth pointing out, especially in patients who undergo repeated orthopedic operations during which, at least in Europe, rifamycin is commonly used for the prevention of local sepsis.
BACKGROUND AND OBJECTIVE: Systemic reactions during anesthesia are commonly attributed to muscle relaxants, hypnotics, macromolecular solutions, latex, or parenteral antibiotics. After exclusion of these different components as causes, we were interested in the potential implication of rifamycin in the systemic reaction, which occurred during anesthesia, and in the immunologic mechanism by which it can trigger this reaction. METHODS: We report four cases of systemic reactions occurring after local administration of rifamycin. Three patients needed orthopedic surgery, and the fourth needed a urethrotomy. Severe systemic reactions occurred in all four patients when the surgeon washed the incision area with a rifamycin solution. All patients correctly responded to appropriate treatment and recovered. Skin tests were performed 2 months after the incident with the drugs used during anesthesia, latex, and rifamycin. To assess the relationship with a possible IgE-mediated mechanism, two in vitro tests were concomitantly performed to evaluate the cell reactivity to rifamycin: (1) determination of histamine release from peripheral basophils and (2) platelet cytotoxicity test, which explored the presence on platelets of specific IgE antibodies bound to the low-affinity receptor for IgE. RESULTS: Skin tests were performed with different drugs used during surgery, and results were only positive for rifamycin in the four cases, accompanied in two cases by a systemic reaction. Histamine release from basophils was positive in three of four patients. The platelet cytotoxicity test results were positive in all four cases. CONCLUSION: It appears that rifamycin, used locally during surgery, is apt to trigger severe systemic anaphylactic reactions, which are linked to an IgE-related process. This situation is worth pointing out, especially in patients who undergo repeated orthopedic operations during which, at least in Europe, rifamycin is commonly used for the prevention of local sepsis.