MOA: Same as Penicillin, So it have more effect on Gram +ve - Cidal
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For convenience, they have been grouped into “generations” that largely correlate with their spectrum of activity, with some exceptions.
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cephalosporins have some cross-allergenicity with penicillins However, using any cephalosporin in a patient with a penicillin allergy is a matter of balancing risks and benefits.
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The cephalosporins are generally more resistant to beta-lactamases than penicillins are.
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Beta-lactamases that are active against penicillins but inactive against cephalosporins are called penicillinases. Beta-lactamases that inactivate cephalosporins (cephalosporinases)
Pharmacokinetics
Absorption: Oral better be separated from food BBB: Only new drugs (3rd and more) Excretion: Mainly (1st/2nd) Renal and Biliary (3rd/4th
Antibacterial spectrum: They are divided into 1st (same as penicillin) , 2nd, 3rd (reverse of first + psuodomonas), and 4th (Anaerobic) generations. In general, the activity against gram-positive bacteria decreases from first to third generation while activity against gram-negative organisms increases.
Generations Cephalosporins
Therapeutic Uses (Most Urgent)
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M: Bacterial Meningitis: (3rd Generation) Cefotaxime and Ceftriaxone
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O: Osteomylitis
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S: Skin Infections
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T: Typhoid (Biliary Infection) (3rd Generation) Cefoprazone or Ceftriaxone
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U: UTI (E.Coli) (3rd/4th)
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R: RTI •
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G: Gonorrhea (Penicillin Resistant) IM Ceftriaxone
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E: ENT Infections
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N: Intestinal Infections
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T: Topical • + Pseudomanl Infections.
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Severe undiagnosed sepsis especially in immunosuppressed patient. 3rd 4th gen
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Treatment of infection of respiratory tract, urinary tract, skin, soft tissue, bones and joints due to susceptible organisms.
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Gram-negative bacterial meningitis may be treated by cefotaxime (third generation) and Ceftriaxone that reach the C.N.S.
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Biliary infection: 3rd generation (cefoperazone or ceftriaxone).
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Gonorrhoea due to penicillin-resistant Gonococci. It is treated by single IM injection of ceftriaxone.
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Pseudomonal infection .
Adverse effects – penicillin like adverse effects
(All Nephrotoxins Dislike Prothrombin)
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ALL: 1st and 2nd do not use after failed or allergic penicillin treatment
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Nephrotoxins: Nephrotoxic 1st & 2nd. Increased w/ diuretics or w/ nephrotoxic agents (Aminoglycosides).
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Dislike: Disulfram like action •
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Prothrombin: Some of the new drugs causes prothrombin/Platelet dysfunction (3rd) •
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Superinfection (Most antibiotic causing polyps) • Treated with Metronidazole or Vancomycin
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1-Allergic reactions, such as rash, urticaria, fever, serum sickness, hemolytic anemia, and eosinophilia. Because of the similarities in structure between the cephalosporins and penicillins, it is not surprising that patients, who are hypersensitive to penicillin occasionally exhibit similar sensitivity when treated with a cephalosporin (cross resistance). Therefore, it is important to inquire about both penicillin and cephalosporin hypersensitivity, especially the immediate variety, before administering any of these agents.
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2-Nephrotoxicity is potentiated by the simultaneous use of diuretics (e.g. thiazide) or nephrotoxic agents such as aminoglycosides. It is less with oral preparations.
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3-Superinfections with Pseudomonas, Klebsiella, Enterobacter, E. coli, Proteus, Serratia and Candida have been reported leading to diarrhea.
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4-Hypoprothrombinemea, thrombocytopenia and/or platelet dysfunction*** are new adverse effects of selected extended-spectrum cephalosporins .
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5- A disulfiram like reaction: has also been noted with some of these agents, such as cefoperazone if it is given with alcohol because they block the second step in alcohol oxidation which results in the accumulation of acetaldehyde.
CEPHALOSPORIN / BETA-LACTAMASE INHIBITOR COMBINATIONS
ceftazidime/avibactam, ceftolozane/tazobactam