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Pharmacotherapy 2 Exam 3: TB and C. diff

Terms in this set (49)

how many TB cases were there in 2018?
9025
discuss TB trends in Alabama from 2017 to 2020
2017 = 120

2019 = 87

2020 = 75
in what populations is TB seen more commonly in?
HIV patients, transplant recipients, cancer patients

people living in crowded conditions

substance abusers

racial and ethnic minorities (29% in Hispanic, 28% in Asian, 25% in African Americans, 16% in White
true or false: if a patient's skin test is positive, they have active TB
false - if they do not have symptoms they may have latent TB
how is latent TB treated?
rifampin QD for 4 months
if there is high clinical suspicion of active TB, how is it treated?
two months of isoniazid 5 mg/kg, rifampin 10 mg/kg, ethambutol (Myambutol) 15-25 mg/kg, and pyrazinamide 15-30 mg/kg

- reevaluation & cultures obtained at 8 weeks

if the culture is negative and there is no change in symptoms d/c therapy

if the culture is negative and there is radiologic/symptom improvement diagnose as culture-negative TB and treat with isoniazid 5 mg/kg & rifampin 10 mg/kg for 7 months (9 months total)
which of the following initial TB medications can be d/c if susceptibility tests show no drug resistance to any of the four medications (usually takes a week or more to get results)?

isoniazide
rifampin
ethambutol
pyrazinamide
ethambutol
what drugs do we d/c during the continuation phase when treating TB?

isoniazide
rifampin
ethambutol
pyrazinamide
pyrazinamide & ethambutol

continue isonizide 5 mg/kg and rifampin 10 mg/kg QD for 7 months (total of 9 months therapy)
TB drugs are dosed based on?
ideal body weight


isoniazid: 5 mg/kg (300 mg max)

rifampin: 10 mg/kg (600 mg max)

pyrazinamide: 15-30 mg/kg (2 g max)

ethambutol: 15-25 mg/kg (1.6 g max)
true or false: c. difficile is a spore producing, gram negative, anaerobic bacteria that is the leading cause of hospital-associated GI illness
false - spore producing, gram positive, anaerobic bacteria
how is C. diff transmitted?
oral fecal route

(part of normal GI flora, but antibiotics change the normal flora resulting in proliferation or selection of toxin producers)
what is the primary pathogen responsible for antibiotic-associated colitis?
C. diff
what toxins does C. diff produce?
toxin A and toxin B

(responsible for intestinal mucosa inflammation, membrane leakage, and diarrhea)


(symptoms range from asymptomatic to mild diarrhea, to colitis, to pseudomembranous colitis)
what is the epidemic strain of C. diff that is highly resistant to fluoroquinolones?
BI/NAP1/027

(produces higher levels of toxin A, toxin B, and binary toxin)
how does the C. diff strain BI/NAP1/027 adhere to colonic cells better?
dysfunctional tcdC gene such that toxin production is not inhibited

(also has higher spore state under stress)

(higher relapse rates and greater mortality)
describe the patho of C. diff
release of toxin A and B causes inflammation and mucosal injury to the colon = colitis

the toxins attract WBCs to the area and may protect, but if not mild diarrhea occurs

the toxins can kill the lining of the intestines causing it to fall off and mix with the WBCs causing yellow patches (pseudomembranous colitis)
true or false: C diff is the most common nosocomial infection linked to health care usage in the US
true - 67% acquired in hospital setting
what are the risk factors associated with C. diff
recent antibiotics (3x higher 2 months after therapy)
• multiple antibiotics
• > 10 days of therapy

duration of hospitalization

65+ years old

chemotherapy

etc:
• manipulation of GI tract (tube feeding, surgery)

• PPI, H2 antagonist use
true or false: vancomycin is useful for treating C. diff because it cannot cause C. diff infections
false - it can cause it and treat it
restricting the use of which antibiotics may be useful in preventing C. diff infections?

amoxicillin
vancomycin
linezolid
cephalosporin
erythromycin
clindamycin
cephalosporin

clindamycin
true or false: probiotics are recommended for the prevention of C. diff
false
a patient presents to your pharmacy after a C. diff infection to pick up her omeprazole prescription. what should you do
dont give it to her - PPIs, Tums, and H2As can complicate C. diff
how is C. diff diagnosed?
3 or more unformed stools in 24 or fewer hours - confirmed by a stool test positive for C. difficile or colonoscopic findings demonstrating pseudomembranous colitis
true or false: repeat testing for C. diff is encouraged due to likelihood of false negatives.
false - repeat testing and testing for a cure is not recommended

(test can be positive up to 30 days after symptoms end)
define the CDI clinical definition and treatment:

initial episode, non-severe
WBC ≤ 15,000 and SCr. < 1.5 + diarrhea

treatment:
• vancomycin 125 mg QID for 10 days

alt:
• fidaxomicin 200 mg BID for 10 days
• metronidazole 500 mg TID PO for 10 days


(same as initial episode, severe)
define the CDI clinical definition and treatment:

initial episode, severe
albumin < 3 + WBC > 15,000 OR SCr > 1.5 (or abdominal tenderness)

treatment:
• vancomycin 125 mg QID PO for 10-14 days
a patient presents with CDI for the first time, hypotension with shock, ileus, and megacolon. how is their CDI defined and how should we treat them?
1st episode - fulminant

treatment: vancomycin 500 mg QID PO or NG tube + metronidazole 500 mg IV q8h

• if additional distension/ileus/toxic colitis is present add vancomycin per rectum 500 mg in 500 mL QID
how is first recurrence of CDI treated?
• if metronidazole was used 1st time: vancomycin 125 mg PO QID x 10 days or


• if vancomycin was used for initial episode: fidaxomicin 200 mg BID x 10 days
how is second and subsequent CDI infections treated?
• vancomycin 125 mg PO QID x 10 days + vancomycin pulsed regimen (125 mg QID for 10-14 days, BID x 7 days, QD x 7 days, then every 2-3 days for 2-8 weeks)
true or false: IV vancomycin can be used to treat CDI
false - noooooo IV stays systemic. have to use oral

(this will absolutely be on the exam)
true or false: vancomycin requires renal/hepatic dosage adjustments
false - none
AEs of vancomycin PO
abdominal pain

flatulence

vomiting and diarrhea


monitoring is not required
true or false: serum concentrations need to be monitored for vancomycin
false - they dont need to be monitored

(also no renal/hepatic adjustments)
true or false: Flagyl does not require renal adjustments, but may need to be decreased in severe hepatic impairment
true

(avoid EtOH 3 days after; CI in pregnancy/breastfeeding and patients with neurological disease)
AEs of Flagyl
HA

N/V/D (but less diarrhea than vancomycin)

dry mouth

metallic taste

dark urine
true or false: Flagyl can be used to treat CDI in pregnant patients
false - CI in pregnancy and breastfeeding and neurological diseases

(Flagyl = metronidazole)
true or false: Dificid is inferior to vancomycin in the treatment of CDI
false - non inferior

(also has 6-10 post antibiotic effects)


(Dificid = fidaxomicin)
true or false: both vancomycin PO and Dificid are not systemically absorbed
true

(Dificid = fidaxomicin)

(no renal/hepatic adjustments)
which of the following medications would be the best option in a pregnant patient presenting with 1st episode, non-severe CDI?

metronidazole 500 mg PO TID x 10 days
vancomycin 125 PO QID x 10 days
fidaxomicin 200 mg BID x 10 days
vancomycin 125 mg QID x 10 days

(metronidazole/Flagyl and fidaxomicin/Dificid are CI in pregnancy/breastfeeding)
true or false: Dificid can be used to treat CDI in children
false - CI in pregnancy/breastfeeding and children
true or false: fidaxomicin can be administered without regard to food
true - with or without food

(AEs: N/V, abdominal pain, GI bleeding)
how is recurrent CDI defined?
CDI within 8 weeks of completion of therapy
what is the criteria for severe complicated (fulminant) CDI?
admission to ICU, fever, ileus or abdominal distension, mental status changes,

WBCs ≥ 35,000 or < 2000 cells/mm

serum lactate > 2.2 mmol/L or

end organ failure
true or false: occurrence of CDI after 8 weeks of initial treatment completion is known as recurrent CDI
false - that would be reinfection
true or false: metronidazole is used for 2nd and subsequent recurrences
false - do not use beyond the first recurrence of CDI or for long term therapy due to potential of neurotoxicity
when do we consider a fecal microbiota transplant?
3rd recurrence
ROA for fecal microbiota transplant
NG tube, colonscopy, or edema


(no side effects)
which of the following treatments for CDI has no side effects?

metronidazole
fidaxomicin
vancomycin
fecal microbiota transplant
fecal microbiota transplant
true or false: fresh stool samples are preferred for fecal microbiota transplant
false - frozen works just as well as freshly donated
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