Antibiotics in Pharyngitis and Rheumatic Fever Treatment

Penicillin V

• Administered orally, achieving lower levels than parenteral benzylpenicillin
• Used primarily against Streptococcus pyogenes in the treatment of pharyngitis and the prevention of rheumatic fever
• Often replaced by amoxycillin, which has more reliable oral absorption and is less dependent on an empty stomach

Antistaphylococcal Penicillins

• Isoxazolyl penicillins:
  • Cloxacillin, Dicloxacillin, Flucloxacillin, and Oxacillin
  • Used for infections caused by beta-lactamase-producing staphylococci, streptococci, and pneumococci
• Others:
  • Methicillin and Nafcillin
• Isoxazolyl penicillins are suitable for mild to moderate localized staphylococcal infections
• Flucloxacillin is equivalent to cloxacillin but has better oral absorption

Antipseudomonal Penicillins

• Carboxypenicillins:
  • Carbenicillin and Ticarcillin
• Ureidopenicillins:
  • Azlocillin, Mezlocillin, and Piperacillin
• Piperacillin is effective against Pseudomonas and most Enterobacteriaceae
• Carboxypenicillins and ureidopenicillins possess additional effects against Gram-negative organisms

Cephalosporins

• B-Lactam antibiotics similar to penicillins
• Broad-spectrum antibiotics acting by inhibition of cell wall synthesis
• Bactericidal, but inactive against enterococci, MRSA, Legionella, Mycoplasma, and Chlamydia spp.
• Widely used in surgical procedures to reduce the risk of post-operative infections

Classifications of Cephalosporins

• First Generation:
  • Cephalexin, Cefazolin, Cephalothin, and Cephradine
  • Active against Gram-positive cocci, but not enterococci and MRSA
  • Indicated for streptococcal pharyngitis and used as prophylaxis in surgical procedures
• Second Generation:
  • Cefoxitin, Cefuroxime, Cefaclor, and Cefprozil
  • Mainly effective against Gram-negative bacteria
  • Cefoxitin active against bowel anaerobes, Cefuroxime active against H. influenzae, M. catarrhalis, and S. pneumoniae
• Third Generation:
  • Ceftriaxone, Cefotaxime, Ceftazidime, and Cefoperazone
  • Enhanced Gram-negative activity, effective against H. influenzae, N. meningitidis, N. gonorrhoeae, and P. aeruginosae
  • Ceftriaxone has a long half-life and is not advised in neonates
• Fourth Generation:
  • Cefipime
  • Active against Gram-positive bacteria, with enhanced activity against Pseudomonas

Adverse Effects of Cephalosporins

• Hypersensitivity reactions (anaphylaxis, bronchospasm, urticaria)
• Nephrotoxicity (especially with Cephradine)
• Thrombophlebitis (with i.v. administration)
• Superinfections
• Diarrhea (with oral cephalosporins, Cefoperazone, and Ceftriaxone)
• Cefamandole, Moxalactam, and Cefoperazone may cause bleeding disorders and interactions with alcohol intake