c diff colitis

Question 1

metronidazole indications

Answer 1

• c diff
• oral infections or aspiration pneumonia due to gram -ve in mouth
• surgical and gynaecological infections caused by gram -ve
• protozoal infections inc trich vag, giardiasis, amoebic dysentery

Question 2

Metronidazole spectrum of activity

Answer 2

• anaerobics and protozoa

Question 3

Metronidazole MOA

Answer 3

• enters cells by passive diffusion.
• in anaerobic bacteria, reduced metro = nitroso free radical - binds to DNA causing degredation and cell death. = bactericidal.

aerobic bacteria cannot reduce metro so it does not work

Question 4

metronidazole SE

Answer 4

• GI upset and hypersensitivity reactions

- high doses for long time = neuro issuesl peripheral and optic neuropathy, seizures and encephalopathy

Question 5

CI to metronidazole

Answer 5

its metabolised by cyp450, so reduce dose in severe liver disease.

Question 6

why should you not drink alcohol whilst on metronidazole

Answer 6

• it inhibits ALDH so acetylaldehyde builds in body - you will get disulfiram reaction

Question 7

interactions of metronidazole

Answer 7

• inhibits cyp450 enzymes so reduce metabolism of warfarin and phenytoin
• reverse interaction can occur with cyp450 inducers.
• increased lithium toxicity risk

Question 8

typical startign dose of metronidazole

Answer 8

400mg 8hrly PO

can be rectal, IV, gel too

Question 9

vancomycin indications

Answer 9

• treat gram +ve infection e.g. endocarditis where infection is severe and/or penicillins cannot be used due to resistance e.g. MRSA
• rx of abx associated colitis caused by clost difficile. 2nd line after metronidazole

Question 10

spectrum of activity of vancomycin

Answer 10

• narrow
  gram +Ve esp staph spp, strepp and c diff

vancomycin resistant enterococci are starting

Question 11

MOA vancomycin

Answer 11

• inhibits growth and cross linking of peptidoglycan chains, inhibting synthesis of cell wall of gram +ve. acquired resistance is beginning

Question 12

SE vancomycin

Answer 12

• thrombophlebitis at the infusion site
• if infused rapidly severe adverse reactions; red man syndrome. = erythema, associated with hypotension and bronchospasm
• allergy
• IV; nephrotoxic including renal failure, itnerstitial nephritis, ototoxicity with tinnitus and hearing loss, neutropenia and thrombocytopenia

Question 13

dose reduction of vancomycin is needed in which patients

Answer 13

• renal impairment

- elderly

Question 14

interactions of vancomycin

Answer 14

• increases risk of oto and nephrotoxicity if with aminoglycosides, loop diureics, ciclosporin

Question 15

what is therapeutic window of vancomycin

Answer 15

10-15mg/L

Question 16

what is fidoxamocin used for

Answer 16

3rd line in c diff