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cephalosporin MOA | Bind covalently to active site of transpeptidase enzyme which catalyzes the cross-linking reaction of peptidoglycan polymers in bacterial cell wall synthesis. Bacteria is lysed by osmotic pressure. |
cephalosporins are | penicillinase resistant |
cephalosporins Work | only in actively growing cells. |
cephalosporins are drugs of 1st choice in | Klebsiella infxns |
Cephalosporins are used in | UTI, Klebsiella infxns, Staph infxns(in patients allergic to penicillins..caution due to cross allerginicity), Gram neg sepsis(+gentamicin or tobramycin) |
Drug of 1st choice in H. influenzae inf is | Ceftriaxone |
Cephalosporins MOA | Bactericidal, they inhibit cell wall synthesis. |
Cephalosporins have higher beta-lactimase resistance due to | different side chain than beta lactam ring. |
Cephalosporin Distribution | Good in soft tissue and relatively good in bone. |
Cephalosporin toxicity | GI disturbances after oral administration, Reversible renal impairment requiring dose reduction. Hypersensitivity reactions. |
Cephalosporin metabolism and excretion | Mainly excreted via kidney, w/tubular secretion mechanism like penicillin, cefoperazone(3rg Gen) excreted mainly in bile, cephapirin(1st Gen) and cefotaxime(2nd Gen) biotransformed to less active metabolites. |
Cephalosporin progression from 1st to 3r Gen | broadening in activity against gram-negative bacteria and anaerobes, Decreased activity against gram positive bacteria, increased resistance to inactivation by B-lactamase enzymes |
Cephalosporin chemistry | very similar to penicillin G, Structurally and pharmacalogically similar to penicillins, 10-15% cross sensitivity w/ penicillin so be careful with pts allergic to penicillin |
Gen 1 Cephalosporins | Cephalexin(1), Cephradine, Cephapirin, Cefazolin, Cefadroxil |
Gen 2 Cephalosporins | Cefaclor(1), Cefuroxime Axetil, Cefprozil, Cefoxitin Na, Cefonicid Na, Cefotaxime Na, Cefotetan Disodium |
Gen 3 Cephalosporins | Ceftriaxone Na(1), Ceftazidime, Ceftizoxime, Cefoperazone Na, Cefepime |
Gen 1 Cephalosporins to know | Cephalexin (PO and acid stable), Cefazolin (IM) |
Gen 2 Cephalosporins to know | Cefaclor(PO), Cefotaxime Na(IM) |
Gen 3 Cephalosporins to know | Ceftriaxone Na (H. Influnzae, IM) Ceftazidime (gram neg. sepsis, IM) |
Carbapanems | Imipenem/Cilistatin, Meropenem |
Carbapanems MOA | Bind to penicillin binding protein-2 (PBP-2) + transpeptidase: remarkable degree of penicillinase resistant(by b-lactimase enzymes) |
Carbapanems spectrum | BROADEST of any B lactam (even 3rd gen Cephalosporins): Gram neg and pos (including Pseudomonas), anaerobes (incl. bacteroides |
Carbapanems used in | Mixed infections (abdominal and pelvic wounds...GSW) |
Carbapanems administered | IM |
Carbapanems side effects | NV, C. diff diarrhea, cross allergenicity w/penicillin, phlelbitis GI problems(pseudomembranous colitis) |
Carbapanems Pharmacokinetics | Parenteral use, good tissue distribution except CSF, Excreted in urine, Degradeted by dehydropeptidase in renal tubule. Administered together w/ cilastatin, an inhibitor of dehydropeptidase-1, increases its urinary concentration. |
Cephalosporin resistance development | In US 2% of S. aureus (clinically isolated) are resistant, Definate cross resistance exhibied by staph which are resistant to methicillin-type antibiotics. |
Cephalosporin Drug interactions | probenecid increases blood levels of cephalosporins, esp those excreted primarily by tubular secretions. |