Lecture 12 - pharmacy Flashcards
Percentage of C diff in healthy adults and why doesnt cause infection in these people?
3% and inhibited by normal gut flora
describe the C diff cycle
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
Name two factors that pre dispose C diff infections
elderly and recent Abx use
Symptoms of c diff infection
diarrhoea often with mucus and distinctive smell
also possitive raised WCC, pyrexia, toxic confusional state in the elderly
What can sever c diff cause? Clinical signs of this disease? How is it diagnosed?
1) pseudomembranous colitis
2) abdo distension, high WCC, diarrhoea
3) flexi-sigmoidoscopy
How is C diff managed?
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
When would you consider using PO fidaxomycin to treat c diff?
- severe disease in patients with concurrent abx and other co-morbidities
- or recurrence within 30 days
One positive and one negative to using PO finaxomycin to treat c diff
really expensive but has a lower relapse rate than other treatments
What is used to treat life threatening cases of C diff and non surgical candidates
IV immunoglobulins - prevent relapse
What is a faecal microbiota transplant? when would you use it?
highly effective treatment of CDI. 90% resolution.
use if have chronic relapsing CDI or refractory or acute severe
Which antibiotics can cause antibiotic associated diarrhoea|? Which are high risk?
1) most/ all of them
2) clindamycin, cephalosporins, broad spec penicillins, quinolones , erythromycin (stimulates motility)
How do broad spec antibiotics cause superinfections? example of brad spec?
kill most of the normal human flora - causing overgrowth of resistant bacteria e.g. meropenem
What is MRSA colonisation associated with?
quinolones, increasing age and increased length of stay
How does quinolones increase MRSA susceptibility?
increase bacterial surface fibronectin therefor improves MRSA adhesion
Name other risk factors for C Diff (aside from age and Abx)
NG tubes - bypass stomach which usually kills microbes with acid
PPIs - raises stomach PH therefore aim to reduce dose/stop
How is c diff prevented?
- 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
What is therapeutic drug monitoring? Example of a drug?
when a drug has a narrow therapeutic window then needs to be monitored to prevent toxicity / check efficacy
gentamycin and vancomycin
Describe the two types of dosing available for gentamycin
multiple daily - dosing 3-5mg/kg in divided doses - used in pregnancy
once daily - 4-7mg/kg/day
How is gentamicin dosage monitored?
multiple daily - is monitored at peak and trough around 3rd or 4th dose
once daily - only troughs are monitered
Target range for gentamycin dosage?
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)
What must be monitored with gentamicin use?
renal function - creatinine clearence and urine output
TWICE weekly
Toxicity associated with gentamycin?
nephrotoxicity and ototoxicity (risk increased by other nephrotoxic drugs)
If renal function has declined when a patient is on gentamycin - what should you do?
measure trough levels !!
once a day = await result before re-dosing
multiple doses a day = can re-dose
