Paper II
2016 October (Supplementary) (2010 Scheme) · 40 marks · 120 min

Question

A 50 years old lady complains of pain in the throat and has been diagnosed to have streptococcal tonsillitis. Answer the following:

  • (a) Name two appropriate drugs for it. 1 mark(s)
  • (b) Name two bactericidal and two bacteriostatic drugs 1 mark(s)
  • (c) Explain briefly the mechanism of action of penicillins 2 mark(s)
  • (d) What are the adverse effects of amino glycosides. 2 mark(s)
Q16 marksEssays

Answer

(a) Two appropriate drugs for streptococcal tonsillitis

  • Penicillin V (or Amoxicillin)
  • Erythromycin (alternative in penicillin allergy)

(b) Bactericidal and bacteriostatic drugs

  • Bactericidal: Penicillin, Aminoglycosides (e.g., Gentamicin)
  • Bacteriostatic: Erythromycin, Tetracycline

(c) Mechanism of action of penicillins

  • Bind irreversibly to penicillin-binding proteins (transpeptidases), inhibiting the cross-linking (transpeptidation) of peptidoglycan chains in the bacterial cell wall
  • This weakens the cell wall, and combined with activation of autolytic enzymes, leads to bacterial cell lysis and death (bactericidal), particularly in actively dividing organisms

(d) Adverse effects of aminoglycosides

  • Ototoxicity (vestibular and auditory, often irreversible)
  • Nephrotoxicity (reversible)
  • Neuromuscular blockade (can worsen myasthenia gravis)
  • Hypersensitivity reactions

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