C / 11 - chloramphenicol, polymixins, antifolate drugs

Question 1

Chloramphenicol
MOA
Spectrum (6)
ROA
Pharmacodynamics
Toxicity
Contraindications

Answer 1

• Protein synthesis inhibitor : binds to the 50s subunit -> bacteriostatic
• Gram (+), Gram (-), anaerobes, Rickettsiae, chlamydia, sprichetes
• Oral, parenteral
• Crosses placenta, BBB, hepatic metabolism
• Grey baby syndrome, aplastic anemia
• Contraindicated in pregnancy and newborns

Question 2

Colicistin / polymyxin E
MOA
Spectrum
Indications
Toxicity

Answer 2

• Polymyxin (cell wall synthesis inhibitor) : damages the cell membrane - bactericidal
• Gram (-) bacteria : pseudomonas
• Limited to topical treatment of superficial skin infections due to severe side effects
• Neurotoxicity, nephrotoxicity

Question 3

What do anti folate drugs do?

Answer 3

They inhibit nucleic acid synthesis by inhibiting the folic acid synthesis pathway (required for na synthesis)

Question 4

2 examples of anti-folate drugs?

Answer 4

• Sulfamethoxazole + trimethoprim
• Proguanil

Question 5

Sulfamethoxazole + trimethoprim
MOA
Spectrum
Indications
Toxicity

Answer 5

• MOA
  x Bactericidal when used together
  x Sulfamethoxazole : weak acid with intermediate action (10-12h) / trimethorprim : weak base with good penetration
• Gram (+) and (-) bacteria, nocardia, h. influenzae, toxoplasma gondii
• Urinary and respiratory tract infections, ear infections
• Hypersensitivity, GI symptoms, BM suppression

Question 6

Proguanil
Indication
ROA

Answer 6

• Malaria prophylaxis
• Oral