antibiotics (Subject) / Cephalosporins (Lesson)

This lesson was created by eysnirmgard.

Learn lesson

back  |  next 1 / 1

• Mechanism and Mode of action PBP-enzyme-inhibition bactericidal time-dependent
• Resistance ab ovo: acid fast (Mycoplasma, Mycobacterium, Rickettsia, Chlamydia) beta-lactamases:    - 1. gen.: resistant against lactamases of Gr+ Cocci, NOT against Gr- bacteria    - 2. gen.: not very resistant against Gr- bacteria    - 3. & 4. gen.: Gr+ and Gr- PBP-mutation: MRSA, MRSP
• microbial spectrum 1. gen.: Gr+ cocci (Strep., Staph., Clostr., Bacillus, Corynebacterium) -> mastitis, metritis, dermatitis, wound infections, otitis, UTI (caused by Gr+), respiratory infection 2. gen.: less in Gr+, more in Gr- (and anaerobs (E. coli, Salmonella, Klebsiella)) -> dermatitis, UTI, otitis 3. gen.: weak in Gr+, very good in Gr- (and anaerobes) -> bacteraemia, septicaemia, pneumonia -> cefoperazone: Pseudomonas -> ceftazidime: Pseudomonas 4. gen.: Gr+ and Gr- (not pseudomonas) -> mastitis, UTI, respiratory tract infections, GIT infections -> mainly in large animals
• Application 1.: PO: cefalexin, cefadroxil parenteral: cefalexin, cefapirin, cefazolin 2.: cefuroxime PO + parenteral 3. & 4.: parenteral
• Cefalexin dose dog + cat: PO, SC, IM 15-25 mg/kg BID
• Ceftiofur dose cattle: SC, IM 6.6 mg/kg (CCFA) swine: SC, IM 5 mg/kg (CCFA) horse: - SC, IM 6.6 mg/kg (CCFA) - SC, IM 2.2 - 4.4 mg/kg (HCl)
• Ceftriaxone dose dog, cat: IV, IM 25-50 mg/kg SID, BID horse: IV 25 mg/kg BID (not authorized)
• Distribution in general, not very good exception: cefotaxime, ceftriaxone -> penetrate special barriers -> used in osteomyelitis, meningitis
• metabolism hyrophilic -> liver-metabolism unsignificant -> can be used in liver-failure patients
• excretion via urine exception: cefoperazone, ceftriaxone -> via bile -> can be used in kidney-failure patients
• Advertisement
• Half-life can be altered by adding substances: - ceftiofur-sodium: very fast action -> doa: 1 day - ceftiofur-HCl: very fast -> doa: 1 day - ceftiofur-CCFA (ceftiofur crystalline free acid): slow -> doa: 1,5 weeks -> metabolized to the antibiotically active substance desfuroyl ceftiofur
• side effects irritation at sight of injection when given IM, SC (cefovecin doesn't irritate) allergy - 5% cross allergy (patients with penicillin-allergy are 5% likely to be allergic to cephalosporins) dysbacteriosis (especially in herbivore-rodents and horses) haematological alterations: anaemia, thrombocytpenia, neutropenia mild nephrotoxicity: enhanced when combined with aminoglycosides
• Indications mastitis, metritis dermatitis otitis UTI respiratory infections Pseudomonas infections meningitis, encephalitis, osteomyelitis pre-operative prophylaxis

back  |  next 1 / 1