Anaerobic Antimicrobials

Question 1

Give some examples

Answer 1

METRONIDAZOLE

Question 2

What are the indications for use

Answer 2

• Abx ass colitis (C diff/ gram +ve anaerobes)
• Oral infections/ aspiration pneumonia - gram-ve anaerobes
• Surgical/ gynae infections = gram -ve
• Protozoal infection - Giardiasis/ dysentry/ trichomonal

Question 3

What are the mechanisms of action

Answer 3

• Enters bacterial cells by passive diffusion
• Reduced by bacteria to generate a nitroso free radical that binds to DNA
• Reduces synthesis & causes widespread damage/ DNA degradation & cell death.

Question 4

What are the side effects

Answer 4

• GI upset
• Hypersensitivity
• Alcohol-flushing headache
• Disulfiram-like reaction
• Long-term peripheral + optic neuropathy
• seizures
• encephalopathy

Question 5

What are the contra-indications

Answer 5

• Severe liver disease

- Caution in alcoholics

Question 6

What are the interactions

Answer 6

• Inhibit cytochrome P450 enzymes
• increase plasma conc of drugs metabolised by enzyme (WARFARIN, PHENYTOIN)
• Can increase lithium toxicity

Question 7

What should you tell the patient

Answer 7

• Alcohol should not be drunk!!!