ATC Vet Code: QJ01CA01
Pharmacotherapeutic group
Antibacterials for systemic use, β-lactam antibacterials, enicillins, penicillins with extended spectrum.
Pharmacodynamic properties
Ampicillin is a beta-lactam antibiotic which has bactericidal activity against mainly Gram-positive bacteria and some Gram-negative aerobes. It is sensitive to beta-lactamase (penicillinase) inactivation. It is widely distributed in the extracellular fluids after absorption, and eliminated almost entirely by the kidneys.
Bioavailability studies indicate that a minimum duration of activity of 48 hours can be expected following a single injection.
Pharmacokinetic properties
Amfipen LA, containing ampicillin anhydrate in a long acting base, has been especially developed to overcome the disadvantage of frequent administrations required for short-acting ampicillin formulations. Blood level studies clearly show that the injection interval can be extended to at least 48 hours instead of the usual 12-24 hours.
After an initial peak at one hour after injection, the ampicillin concentrations decline slowly and gradually over the 48 hour period and 34 to 50 % of the ampicillin becomes available on the second day after injection.
Animal studies have demonstrated that ampicillin is evenly distributed throughout the body tissues and is concentrated in the liver and the kidneys. It is excreted unchanged in the urine. Investigations have shown that ampicillin is excreted in high concentration in the bile.