Fidaxomicin

Question 1

Fidaxomicin

Answer 1

Has one use: treatment of C. diff

Is a nonabsorbed macrocyclic antibiotic with a narrow spectrum of activity

Ideal for treating C. diff because it is sparing to the normal flora of the GI tract, allowing to be restored during therapy

Question 2

Fidaxomicin Spectrum

Answer 2

Good
C. diff

Poor
Anything else, including Bacteroides species and enteric GNRs

Question 3

Fidaxomicin Adverse Effects

Answer 3

Because it’s nonabsorbed, would be expected to have few systemic adverse effects
Most adverse effects associated with C. diff (N/D/abdominal pain/cramping)

Question 4

Fidaxomicin Important Facts

Answer 4

Showed similar clinical efficacy to Vanco capsules
Was superior in preventing recurrence of C. diff (may be preferred for patients at high risk of recurrence)

Normal flora sparing effect likely negated when given with oral Vanco or Metronid
Two drugs not better than one; should probably avoid the combo

Expensive; patient assistance programs available
Cheaper than an admission for C. diff relapse
Determining the best candidates is a challenge

Good for
C. diff infections ranging from diarrhea to pseudomembranous colitis

Has important benefit in lowering C. diff infection recurrence
Due to cost, must carefully determine who is most likely to benefit