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 misuse are among the few viable antibiotics. Antibiotics have no effect on viral infections such as the common cold. They are also ineffective against sore throats, which are usually viral and self-resolving. Most cases of bronchitis (90–95%) are viral as well, passing after a few weeks—the use of antibiotics against bronchitis is superfluous and can put the patient at risk of suffering adverse reactions. Official guidelines by the American Heart Association for dental antibiotic prophylaxis call for the administration of antibiotics to prevent infective endocarditis. Though the current (2007) guidelines dictate more restricted antibiotic use, many dentists and dental patients follow