Respiratory infections, including bronchitis, pharyngitis
Sinusitis
Sepsis
Whooping cough, to prevent and treat secondary infectionsAmpicillin used to also be used to treat gonorrhea, but there are now too many strains resistant to penicillins. Bacteria
Ampicillin is used to treat infections by many gram-positive and gram-negative bacteria. It was the first "broad spectrum" penicillin with activity against gram-positive bacteria, including Streptococcus pneumoniae, Streptococcus pyogenes, some isolates of Staphylococcus aureus (but not penicillin-resistant or methicillin-resistant strains), Trueperella, and some Enterococcus. It is one of the few antibiotics that works against multidrug resistant Enterococcus faecalis and E. faecium. Activity against gram-negative bacteria includes Neisseria meningitidis, some Haemophilus influenzae, and some of the Enterobacteriaceae (though most Enterobacteriaceae and Pseudomonas are resistant). Its spectrum of activity is enhanced by co-administration of sulbactam, a drug that inhibits beta lactamase, an enzyme produced by bacteria to inactivate ampicillin and related antibiotics. It is sometimes used in combination with other antibiotics that have different mechanisms of action, like vancomycin, linezolid, daptomycin, and tigecycline. Available forms
Ampicillin can be administered by mouth, an intramuscular injection (shot) or by intravenous infusion. The oral form, available as capsules or oral suspensions, is not given as an initial treatment for severe infections, but rather as a follow-up to an IM or IV injection. For IV and IM injections, ampicillin is kept as a powder that must be reconstituted.IV injections must be given slowly, as rapid IV injections can lead to convulsive seizures.
In the kidneys, it is filtered out mostly by tubular secretion; some also undergoes glomerular filtration, and the rest is excreted in the feces and bile. Hetacillin and pivampicillin are ampicillin esters that have been developed to increase bioavailability. History
Ampicillin has been used extensively to treat bacterial infections since 1961. Until the introduction of ampicillin by the British company Beecham, penicillin therapies had only been effective against gram-positive organisms such as staphylococci and streptococci. Ampicillin (originally branded as "Penbritin") also demonstrated activity against gram-negative organisms such as H. influenzae, coliforms, and Proteus spp. Cost
Ampicillin is relatively inexpensive. In the United States, it is available as a generic medication. Veterinary use
In veterinary medicine, ampicillin is used in cats, dogs, and farm animals to treat:
Anal gland infections
Cutaneous infections, such as abscesses, cellulitis, and pustular dermatitis
E. coli and Salmonella infections in cattle, sheep, and goats (oral form). Ampicillin use for this purpose had declined as bacterial resistance has increased. Mastitis in sows
Mixed aerobic–anaerobic infections, such as from cat bites
Multidrug-resistant Enterococcus faecalis and E. faecium
Prophylactic use in poultry against Salmonella and sepsis from E. coli or Staphylococcus aureus
Respiratory tract infections, including tonsilitis, bovine respiratory disease, shipping fever, bronchopneumonia, and calf and bovine pneumonia
Urinary tract infections in dogsHorses are generally not treated with ampicillin, as they have low bioavailability of beta-lactams.The half-life in animals is around that same of that in humans (just over an hour). Oral absorption is less than 50% in cats and dogs, and less than 4% in horses.