Β-lactam antibiotic reactions to any β-lactam antibiotic may occur in up to 10% of patients receiving that agent (a small fraction of which are truly IgE-mediated allergic reactions, see amoxicillin rash). Anaphylaxis will occur in approximately 0.01% of patients. There is perhaps a 5%-10% cross-sensitivity between penicillin-derivatives, cephalosporins, and carbapenems; but this figure has been challenged by various investigators. Nevertheless, the risk of cross-reactivity is sufficient to warrant the contraindication of all β-lactam antibiotics in patients with a history of severe allergic reactions (urticaria, anaphylaxis, interstitial nephritis) to any β-lactam antibiotic. A Jarisch–Herxheimer reaction may occur after initial treatment of a spirochetal
Antibiotic prophylaxis to the serious problem of superbugs (which are bred in antibiotic-rich environments) the Food and Drug Administration issued a guidance document in December 2013. The chief public health officer of Canada said four months later that "antibiotics should only be used in animals to treat infection rather than guard against disease or promote growth." The Canadian guidance document calls for "the prudent use of antibiotics in animal agriculture and a gradual phasing out of growth promoting drugs in feed and water over the three years" ending in 2017. Producers will no longer be allowed to continuously feed animals doses of