Lecture 12 - pharmacy

Question 1

Percentage of C diff in healthy adults and why doesnt cause infection in these people?

Answer 1

3% and inhibited by normal gut flora

Question 2

describe the C diff cycle

Answer 2

bacteria swallowed - stomach kills bacteria. spored travel to intestine and germinate. if gut flora is altered (Abx) then colonisation , toxin production and disease can occur - causes diarrhoea (type 6 &7) further spread in environment

Question 3

Name two factors that pre dispose C diff infections

Answer 3

elderly and recent Abx use

Question 4

Symptoms of c diff infection

Answer 4

diarrhoea often with mucus and distinctive smell

also possitive raised WCC, pyrexia, toxic confusional state in the elderly

Question 5

What can sever c diff cause? Clinical signs of this disease? How is it diagnosed?

Answer 5

1) pseudomembranous colitis
2) abdo distension, high WCC, diarrhoea
3) flexi-sigmoidoscopy

Question 6

How is C diff managed?

Answer 6

stool sample is sent for toxins
patient is put in isolation (enteric precautions and hand hygiene)
stool chard and daily monitoring of stools
stop offending antibiotics and stop drugs that may cause diarrhoea

Question 7

When would you consider using PO fidaxomycin to treat c diff?

Answer 7

• severe disease in patients with concurrent abx and other co-morbidities
• or recurrence within 30 days

Question 8

One positive and one negative to using PO finaxomycin to treat c diff

Answer 8

really expensive but has a lower relapse rate than other treatments

Question 9

What is used to treat life threatening cases of C diff and non surgical candidates

Answer 9

IV immunoglobulins - prevent relapse

Question 10

What is a faecal microbiota transplant? when would you use it?

Answer 10

highly effective treatment of CDI. 90% resolution.

use if have chronic relapsing CDI or refractory or acute severe

Question 11

Which antibiotics can cause antibiotic associated diarrhoea|? Which are high risk?

Answer 11

1) most/ all of them

2) clindamycin, cephalosporins, broad spec penicillins, quinolones , erythromycin (stimulates motility)

Question 12

How do broad spec antibiotics cause superinfections? example of brad spec?

Answer 12

kill most of the normal human flora - causing overgrowth of resistant bacteria e.g. meropenem

Question 13

What is MRSA colonisation associated with?

Answer 13

quinolones, increasing age and increased length of stay

Question 14

How does quinolones increase MRSA susceptibility?

Answer 14

increase bacterial surface fibronectin therefor improves MRSA adhesion

Question 15

Name other risk factors for C Diff (aside from age and Abx)

Answer 15

NG tubes - bypass stomach which usually kills microbes with acid
PPIs - raises stomach PH therefore aim to reduce dose/stop

Question 16

How is c diff prevented?

Answer 16

• only using Abx when definite infection
• using narrow spec agents when possible
• using shortest Abx duration possible
• stating duration on drug chart
• reviewing patient transfer and stopping Abx when necessary
• hand hygine

Question 17

What is therapeutic drug monitoring? Example of a drug?

Answer 17

when a drug has a narrow therapeutic window then needs to be monitored to prevent toxicity / check efficacy
gentamycin and vancomycin

Question 18

Describe the two types of dosing available for gentamycin

Answer 18

multiple daily - dosing 3-5mg/kg in divided doses - used in pregnancy
once daily - 4-7mg/kg/day

Question 19

How is gentamicin dosage monitored?

Answer 19

multiple daily - is monitored at peak and trough around 3rd or 4th dose
once daily - only troughs are monitered

Question 20

Target range for gentamycin dosage?

Answer 20

once daily - trough must be below 1mg/L
multiple daily - trough must be below 2mg/L (trough not as low) peak usually 5-10 mg/L (pseudo 7-10, synergy for streptococcal or enterococcal lower 3-5)

Question 21

What must be monitored with gentamicin use?

Answer 21

renal function - creatinine clearence and urine output

TWICE weekly

Question 22

Toxicity associated with gentamycin?

Answer 22

nephrotoxicity and ototoxicity (risk increased by other nephrotoxic drugs)

Question 23

If renal function has declined when a patient is on gentamycin - what should you do?

Answer 23

measure trough levels !!
once a day = await result before re-dosing
multiple doses a day = can re-dose