Cefaclor is an orally administered second-generation cephalosporin. They are very effective against H.influenzae . It is relatively ineffective against Pseudomonas aeruginosa. Ceftriaxone has activity similar to that of cefotaxime. Its longer half-life allows once or twice daily dosing.
Ceftazidime is highly effective against many strains of Pseudomonas aeruginosa.
It is also active against Klebsiella, Serratia, Proteus, E.coli, Enterobacter species and Neisseria. Cefixime and cefpodoxime are new third- generation cephalosporins that can be administered orally. It is rapidly hydrolysed in the intestinal mucosa and blood to release cefuroxime. Relative - history of penicillin allergy. A disulfiram-like reaction may occur.