Omnipen
Omnipen (generic name: Ampicillin) is one of the most widely prescribed antibiotics. It is considered a penicillin and is a close relative of another penicillin, amoxicillin. Unlike penicillin, ampicillin and amoxicillin can penetrate and prevent the growth of certain types of bacteria, called gram-negative bacteria. Ampicillin is used mainly to treat infections of the middle ear, sinuses, bladder, kidney, and uncomplicated gonorrhea. It also is used intravenously to treat meningitis and other serious infections. Ampicillin was approved by the FDA in 1963.
Oral ampicillin (or amoxicillin) is effective against susceptible bacteria causing infections of the middle ear, sinuses, bladder, and kidney. Only mild to moderate infections are treated with oral ampicillin. Bacteria against which ampicillin often is effective include: enterococci, Listeria monocytogenes, Neisseria gonorrhoeae, Neisseria meningitidis, some Hemophilus influenzae, Gardnerella vaginalis, Bordetella pertussis, and some E. coli, Proteus mirabilis, Salmonella, and Shigella. Susceptibilities of bacteria to antibiotics vary from location to location. Thus, some doctors may use ampicillin or amoxicillin first for some infections, whereas other doctors may use more “broad-spectrum” antibiotics.
Omnipen side effects
Allergic reactions are relatively common side effects during therapy with any of the penicillins. These reactions can range from rashes to anaphylaxis, a severe condition in which there may be shock and even death. Rashes occur more frequently with ampicillin than with the other penicillins. The incidence of rash with ampicillin seems to be higher in patients with viral illnesses, such as mononucleosis. Patients with a history of allergic reaction to any other penicillin should not receive ampicillin. Persons who are allergic to the cephalosporin class of antibiotics which is more distantly related to the penicillins (e.g., Ceclor, Keflex, Cefzil) may or may not be allergic to penicillins.
Nausea, vomiting, loss of appetite, diarrhea, and abdominal pain are commonly reported gastrointestinal side effects during ampicillin therapy, but are rarely severe. Diarrhea appears to occur more frequently with ampicillin than with the other penicillins.