Side Effects of Principen (ampicillin)

Principen (ampicillin) is a penicillin antibiotic used to treat infections of the

• middle ear,
• sinuses,
• stomach and intestines,
• bladder, and
• kidney caused by susceptible bacteria.

It also is used for treating

• uncomplicated gonorrhea,
• meningitis,
• endocarditis and
• other serious infections. 

Because of the increased use of antibiotics, many bacterial strains have become resistant to penicillins; bacteria causing serious infections should be tested for resistance against penicillins and other antibiotics.

Common side effects of Principen include:

• nausea,
• vomiting,
• loss of appetite,
• diarrhea,
• abdominal pain,
• rash,
• itching,
• headache,
• confusion and
• dizziness.

Serious side effects of Principen include:

• rare allergic reactions [seizures, severe allergic reactions (anaphylaxis)],
• low platelet or red blood cell count, and
• pseudomembranous colitis (symptoms include diarrhea, fever, abdominal pain, and possibly shock).

Drug interactions of Principen include probenecid, which causes an increase in the amount of ampicillin in the body. 

Use of Principen with allopurinol can increase the incidence of drug-related skin rash. Principen may reduce the effect of BCG live vaccine and Typhoid live vaccine. 

Principen is considered safe during pregnancy. If Principen is used during pregnancy, the potential benefit of ampicillin for the mother should be weighed against the potential risk of side effects in the infant.  

Principen is excreted in breast milk and may cause diarrhea or allergic responses in nursing infants. Consult your doctor before breastfeeding. 

Common side effects of ampicillin include:

• nausea,
• vomiting,
• loss of appetite,
• diarrhea,
• abdominal pain,
• rash,
• itching,
• headache,
• confusion and
• dizziness.

Patients with a history of allergic reactions to other penicillins should not receive ampicillin.

Persons who are allergic to the cephalosporin class of antibiotics, which are related to the penicillins may or may not be allergic to penicillins [for example, cefaclor (Ceclor), cephalexin (Keflex), and cefprozil (Cefzil)].

Serious but rare reactions include seizures, severe allergic reactions (anaphylaxis), and low platelet or red blood cell count.

Ampicillin can alter the normal bacteria in the colon and encourage overgrowth of some bacteria such as Clostridium difficile which causes inflammation of the colon (pseudomembranous colitis).

Patients who develop signs of pseudomembranous colitis after starting ampicillin (diarrhea, fever, abdominal pain, and possibly shock) should contact their physician immediately.

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.

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.

When administered concurrently, the following drugs may interact with ampicillin.

Allopurinol: Increased possibility of skin rash, particularly in hyperuricemic patients may occur.

Bacteriostatic Antibiotics: Chloramphenicol, erythromycins, sulfonamides, or tetracyclines may interfere with the bactericidal effect of penicillins. This has been demonstrated in view, however, the clinical significance of this interaction is not well documented.

Oral Contraceptives: May be less effective and increased breakthrough bleeding may occur.

Probenecid: May decrease renal tubular secretion of ampicillin resulting in increased blood levels and/or ampicillin toxicity.

Drug/Laboratory Test Interaction

After treatment with ampicillin, a false-positive reaction for glucose in the urine may occur with copper sulfate tests (Benedict's solution, Fehling's solution, or Clinitest tablets) but not with enzyme based tests such as Clinistix and Glucose Enzymatic Test Strip USP.