(Broad Spectrum Aminobenzyl Penicillins)

 

• More lipid soluble than pen G so more active against Gram (-)
• Better oral absorption (more stable in acid)
• Just as susceptibile to penicillinase
• Hydrolyze in water.

 

The difference between ampicillin and amoxicillin is that amoxicillin is slightly more lipid soluble than ampicillin. It (may) kill bacteria a little quicker, slightly better more of it is absorbed (and more rapidly). Otherwise, it is essentially the same activity.

Activity Profile (aminopenicillins):

Good as for benzyl Penicillin but also Borrelio, Leptospira, Moraxella

Moderate as for benzyl penicillin and Campylobacter, R. equi, and enterococci

Resistant Constitutive: Bacteroides fragilis, B.

bronchiseptica, Citrobacter, Enterobacter, Klebsiella, other Proteus, P. aeruginosa, Serratia, Y. enterocolitica.Acquired: Actinobacillus, E. coli, P. mirabilis, and Salmonella, and widespread resistant

by Enterobacteriaceae (though they are considered part of the general spectrum).