Mechanism of action The amino group (highlighted in magenta) is present on<unk>  but not penicillin G.<unk>  is in the penicillin group of beta-lactam antibiotics and is part of the aminopenicillin family. It is roughly equivalent to amoxicillin in terms of activity.<unk>  is able to penetrate Gram-positive and some Gram-negative bacteria. It differs from penicillin G, or benzylpenicillin, only by the presence of an amino group. This amino group, present on both<unk>  and amoxicillin, helps these antibiotics pass through the pores of the outer membrane of Gram-negative bacteria, such as E. coli, Proteus mirabilis, Salmonella enterica, and Shigella.<unk>  acts as an irreversible inhibitor of the enzyme transpeptidase, which is needed by bacteria to make the cell wall. It inhibits the third and final stage of bacterial cell wall synthesis in binary fission, which ultimately leads to cell lysis; therefore,<unk>  is usually bacteriolytic. Pharmacokinetics<unk>  is well-absorbed from the GI tract (though food reduces its absorption), and reaches peak concentrations in one to two hours. The bioavailability is around 62% for parenteral routes. Unlike other penicillins, which usually bind 60–90% to plasma proteins,<unk>  binds to only 15–20%.<unk>  is distributed through most tissues, though it is concentrated in the liver and kidneys. It can also be found in the cerebrospinal fluid when the meninges become inflamed (such as, for example, meningitis). Some<unk>  is metabolized by hydrolyzing the beta-lactam ring to penicilloic acid, though most of it is excreted unchanged. 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<unk>  esters that have been developed to increase bioavailability.
Ampicillin
Meropenem
Methicillin
Resistin
Cefotaxime
Vancomycin
Erythromycin
Natamycin