Ampicillin is a penicillinæantibioticæthat fights bacteria.
Ampicillin is used to treat or prevent many different types of infections such as bladder infections,æpneumonia,ægonorrhea,æmeningitis, or infections of the stomach or intestines.
The eruption that is sometimes observed in ampicillin-treated patients with undiagnosedæinfectious mononucleosisæis characterized by a delayed pruritic maculopapular erythematous rash that generally occurs 5 to 10 days after ampicillin therapy is initiated. It is often more severe and extensive and longer in duration than the typical spontaneous eruption of infectiousæmononucleosis, but does not necessarily indicate a lifelong allergy to ampicillin or other penicillin derivatives. Although this type of reaction has been described with penicillin and alsoætetracycline, ampicillin has been implicated most frequently. Therefore, ampicillin may not be suitable in patients suspected of having infectious mononucleosis.
Hypersensitivity reactions have included urticarial rash,æerythemaæmultiforme, exfoliative dermatitis, serum sickness-like reactions,æedema,æhypotension, fever,æeosinophilia,ædyspnea, interstitial nephritis, Henoch-Schonlein purpura, focalæglomerulonephritis,æStevens-Johnson syndrome,æbullous pemphigoid, hypersensitivity myocarditis,ætoxic epidermal necrolysis, and fixed drug eruptions.æAnaphylaxisæis rare (up to 0.2%), but is more common in patients receiving parenteral ampicillin therapy. Erythematous eruptions have been reported in patients with infectious mononucleosis who were given ampicillin.