As with other penicillins, it may be expected that untoward reactions will be essentially limited to sensitivity phenomena. They are more likely to occur in individuals who have previously demonstrated hypersensitivity to penicillin and in those with a history of allergy, asthma, hay fever, or urticaria.
The following adverse reactions have been reported as associated with the use of ampicillin:
Gastrointestinal: glositis, stamatitis, nausea, vomiting, enterocolitis, pseudomembranous colitis, and diarrhea. These reactions are usually associated with oral dosage forms of the drugs.
Hypersensitivity Reactions: An erythematous, mildly pruritic, maculopapular skin rash has been reported fairly frequently. The rash, which usually does not develop within the first week of therapy, may cover the entire body including the soles, palms, and oral mucosa. The eruption usually disappears in three to seven days.
Other hypersensitivity reactions that have been reported are: skin rash, pruritus, urticaria, erythema multiforme, and an occasional case of exfoliative dermatitis. Anaphylaxis is the most serious reaction experienced and has usually been associated with the parenteral dosage form of the drug
Note: Urticaria, other skin rashes, and serum sickness-like reactions may be controlled by antihistamines, and if necessary, systemic corticosteroids. Whenever such reactions occur, ampicillin should be discontinued unless, in the opinion of the physician, the condition being treated is life-threatening, and amenable only to ampicillin therapy. Serious anaphylactoid reactions require emergency measures (see WARNINGS).
Liver: Moderate elevation in serum glutamic oxalaacetic transaminase (SGOT) has been noted, but the significance of this finding is unknown.
Hemic and Lymphatic Systems: Anemia, thrombocytopenia, thrombocytopenic purpura, eosinophilia, leukapenia, and agranulacytosis have been reported during therapy with penicillins. These reactions are usually reversible on discontinuation of therapy and are believed to be hypersensitivity phenomena.
Other: Other adverse reactions that have been reported with the use at ampicillin are laryngeal stride and high fever. An occasional patient may complain of sore mouth or tongue as with any oral penicillin preparation.