Detailed Drug Information:

DRUG CLASS AND MECHANISM: Ampicillin is one of the most widelyprescribed antibiotics. It is considered a penicillin and is a closerelative of another penicillin, amoxicillin. Unlike penicillin, ampicillinand amoxicillin can penetrate and prevent the growth of certain types ofbacteria, called gram-negative bacteria. Ampicillin is used mainly totreat infections of the middle ear, sinuses, bladder, kidney, anduncomplicated gonorrhea. It also is used intravenously to treat meningitisand other serious infections. Ampicillin was approved by the FDA in 1963.

PREPARATIONS: Tablets: 250mg; 500mg. Oral suspension: 100 mg/mL;125 mg/5mL; 250 mg/5mL.

STORAGE: Tablets should be kept between 15°C (59°F) and 30°C (86°F). The solution should be kept refrigerated, andcan be used for up to 14 days after it is reconstituted by the pharmacist.It must be shaken before each use and should be kept well sealed.

PRESCRIBED FOR: Oral ampicillin (or amoxicillin) is effectiveagainst susceptible bacteria causing infections of the middle ear,sinuses, bladder, and kidney. Only mild to moderate infections are treatedwith oral ampicillin. Bacteria against which ampicillin often is effectiveinclude: enterococci, Listeria monocytogenes, Neisseria gonorrhoeae,Neisseria meningitidis, some Hemophilus influenzae, Gardnerella vaginalis,Bordetella pertussis, and some E. coli, Proteus mirabilis, Salmonella, andShigella. Susceptibilities of bacteria to antibiotics vary from locationto location. Thus, some doctors may use ampicillin or amoxicillin firstfor some infections, whereas other doctors may use more "broad-spectrum"antibiotics.

DOSING: Food in the stomach reduces how much and how quicklyampicillin is absorbed. Administration should be either 1 hour prior to or2 hours following a meal for maximal absorption. However, for persons whoexperience nausea or stomach distress after taking ampicillin, it may betaken with meals. Ampicillin most often is given four times a day for 7 to14 days. When used to treat gonorrhea, it is given as a single large dose(for example, seven 500mg capsules) with probenecid. The probenecid slowsdown the elimination of the ampicillin so that the ampicillin remains inthe body longer.

DRUG INTERACTIONS: Probenecid (Benemid), causes an increase inthe amount of ampicillin in the body. This interaction may be used toadvantage. (See Dosing.) Use of ampicillin with allopurinol can increase the incidence of drug-related skin rash. Very high doses of ampicillin (atleast 1 gram or 1000 mg) can decrease the effect of atenolol (Tenormin) bydecreasing its concentration in the blood. Similarly, ampicillin, even innormal doses, can decrease the effectiveness of birth control pills bydecreasing the blood concentrations of the estrogens in the birth controlpills.

PREGNANCY: Ampicillin is considered safe during pregnancy.

NURSING MOTHERS: Ampicillin is excreted in breast milk. No sideeffects have been reported in nursing infants whose mothers have takenampicillin. Concern for side effects such as allergic reactions, ofcourse, exist. Thus, physicians weigh the potential risk of allergy versusthe benefits.

SIDE EFFECTS: Allergic reactions are relatively common sideeffects during therapy with any of the penicillins. These reactions canrange from rashes to anaphylaxis, a severe condition in which there may beshock and even death. Rashes occur more frequently with ampicillin thanwith the other penicillins. The incidence of rash with ampicillin seems tobe higher in patients with viral illnesses, such as mononucleosis.Patients with a history of allergic reaction to any other penicillinshould not receive ampicillin. Persons who are allergic to thecephalosporin class of antibiotics which is more distantly related to thepenicillins (e.g., Ceclor, Keflex, Cefzil) may or may not be allergic topenicillins.

Nausea, vomiting, loss of appetite, diarrhea, and abdominal pain arecommonly reported gastrointestinal side effects during ampicillin therapy,but are rarely severe. Diarrhea appears to occur more frequently withampicillin than with the other penicillins.