In a recent issue of this journal F arbod et al. analyzed the A merican H eart A ssociation’s (AHA) guidelines for the prevention of infective endocarditis (IE) through antibiotic prophylaxis. After reviewing this document as well as others dealing with methods of preventing IE they concluded that adverse events stemming from antibiotic use exceeded the benefits of antibiotic prophylaxis. Unfortunately they bolstered their argument by raising the old and very incorrect canard that “prophylaxis with amoxicillin in a large unselected population, carries a risk of death from anaphylaxis that is five times greater than the risk of developing IE.”
In fact the AHA report specifically and unequivocally states that it is unaware of any reports of fatal anaphylaxis resulting from the administration of amoxicillin in accordance with its guidelines. Furthermore, the National Institute for Health and Clinical Excellence (NICE) clinical guidelines report (“Prophylaxis against infective endocarditis”) prepared for the National Health Service in England and Wales specifically states that the studies that they reviewed did not identify any episodes of anaphylaxis . Lastly, L ee & S hanson in their analysis of the British Commission on Human Medicines and Healthcare Products report state that between 1972 and early 2007 there were a total of eight fatal cases of anaphylaxis associated with amoxicillin, but that five resulted from intravenous administration, and in two cases the route was unknown. They further go on to note that in the only documented case of anaphylaxis associated with oral administration, the dosage differed markedly from suggested prophylaxis regimens in that the patient was taking 250 mg of amoxicillin orally four times per day.
Farbod et al. are entitled to espouse their opinions relative to the appropriateness or lack thereof of administering antibiotic prophylactically to prevent endocarditis but they should not rise the specter of anaphylaxis in defense of their position.