Name: Ampicillin (Omnipen, Polycillin)
Class: Penicillin (Aminopenicillin)
Mech.: Binds to PBPs, blocks activity of transpeptidases in terminal stages of cell wall formation. Bactericidal.
Absorption: Acid stable. Good oral, but food interferes. IM, IV.
Distribution: Widely distributed, little CSF unless meninges inflamed.
Metab.:
Excretion, t½: Rapidly elim. by kidneys (probenecid blocks excretion), small amt. in bile.
Toxicity/S.E.s: diarrhea, non-allergy skin rash, hypersensitivity (1-10%), superinfection.
Utility: More effective against gram -s (esp. Proteus, H. influenzae, E. coli, P. mirabilis). Less active than Pen. G against gram+ cocci.
Special Features: Broad spectrum.