Penicillin drug reaction

A penicillin drug reaction is an adverse drug reaction associated with the use of penicillin.

Common adverse drug reactions (≥1% of patients) associated with use of the penicillins include diarrhea, hypersensitivity, nausea, rash, neurotoxicity, urticaria, and superinfection (including candidiasis). Infrequent adverse effects (0.1–1% of patients) include fever, vomiting, erythema, dermatitis, angioedema, seizures (especially in people with epilepsy), and pseudomembranous colitis.

Pain and inflammation at the injection site is also common for parenterally administered benzathine benzylpenicillin, benzylpenicillin, and, to a lesser extent, procaine benzylpenicillin.

Although penicillin is still the most commonly reported allergy, less than 20% of all patients that believe that they have a penicillin allergy are truly allergic to penicillin; nevertheless, penicillin is still the most common cause of severe allergic drug reactions.

Allergic reactions to any β-lactam antibiotic may occur in up to 1% of patients receiving that agent. The allergic reaction is a Type I hypersensitivity reaction. Anaphylaxis will occur in approximately 0.01% of patients. It has previously been accepted that there was up to a 10% cross-sensitivity between penicillin-derivatives, cephalosporins, and carbapenems, due to the sharing of the β-lactam ring. However recent assessments have shown no increased risk for cross-allergy for 2nd generation or later cephalosporins. Recent papers have shown that a major feature in determining immunological reactions is the similarity of the side chain of first generation cephalosporins to penicillins, rather than the β-lactam structure that they share.