抗生素精品课件内酰胺类抗生素_1.ppt

β-Lactam antibiotics Prophylaxis and treatment Ask allergic history carefully Must make skin test, the injection of these drugs is made up before it is injected. As a number of these drugs are replaced, the skin test must be done again. β-Lactam antibiotics After every injection, all of patients must be observed for half an hour, and the drugs for an emergency treatment are prepared at any time. Adrenaline (epinephrine) is the first drug for the treatment of anaphylactic shock. β-Lactam antibiotics Semisynthesis penicillins Orally penicillins Penicillins resistant to β-lactamase Extended-spectrum penicillins Antipseudomonal penicillins Penicillins effect on Gˉ bacteria β-Lactam antibiotics Cephalosporins The nucleus of the cephalosporins, 7-aminocephalosporanic acid, bears a close resemblance to 6-aminopenicillanic acid. β-Lactam antibiotics The intrinsic antimicrobial activity of natural cephalosporins is low, but the attachment of various R1 and R2 groups has yielded drugs of good therapeutic activity and low toxicity. 7-aminocephalosporanic acid nucleus (7-ACA) β-Lactam antibiotics Classification the first generation agents the second generations agents the third generation agents the fourth generation agents the first generation agents Characters : have powerful antimicrobial effects on G+ and staphylococcal that can produce β-lactamase, less effects on Gˉ, renal function decrease Agents : cefalotin, cefazolin, cefradine, cefadroxil, the second generations agents Characters : have more powerful against Gˉ, less effect on G+, a part of them are effective against anaerobe, have nephrotoxicity, Agents : cefuroxime, loracarbef, the third generation agents Characters : have less activity against G+, much more activity against Gˉ, higher stability for beta-lactamase, extended spectrum, high permeability, widely distribution, almost no nephrotoxicity, Agents : ceftazidime, ceferiaxone, the fourth generation agents Characters :