Mechanism of action of drugs

I.Cellwall synthesis Inhibitors

1.Beta lactams

  1. Penicillins and cephalosporins
  2. Inhibit cell wall cross linking.


II.Inhibitors of protein synthesis

Bind to 50 S subunit

  1. Macrolides-Erythromycin
  2. Lincosamides-Clindamycin
  3. Chloramphenicol
  4. Quinupristin/Dalfopristin
  5. Linezolid

Bind to 30S subunit

  1. Tetracycline-Binds to 30 S subunit
  2. Aminoglycosides-Gentamycin-Bind to 30 S subunit

Mupirocin-Inhibits Isoleucine tRNA synthetase

III.Inhibitors of Cell metabolism

  1. Sulfonamides and trimethoprim-Competitively inhibit enzymes involved in folic acid synthesis

IV.Drugs inhibiting nucleic acid synthesis

  1. Rifampin-Inhibit DNA dependant RNA polymerases
  2. Metronidazole-Intracellularly generates reactive intermediates that damage DNA by electron transfer system.

V.Inhibitors of DNA synthesis

  1. Quinolones-Ciprofloxacin-Inhibit DNA gyrase(A subunt) and topoisomerase V
  2. Novobiocin-Inhibits DNA gyrase(B subunit)

VI.Drugs acting on cell membranes

  1. Polymixins-Polymixin B-Disrupts membrane permeability by charge alteration
  2. Gramicidin-Forms pores in cell membrane
  3. Daptomycin-Forms channels that disrupt membrane potential

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