Fidaxomicin
DIFICID
Pronunciation: fye-dax-oe-MYE-sin
What it isNarrow-spectrum macrocyclic inhibiting bacterial RNA polymerase; Clostridioides difficile infection.
Why this oneIt spares the protective gut flora, so recurrence is markedly lower than with vancomycin.
What limits itCost often blocks first-line use; hypersensitivity can end treatment. Minimal absorption means it cannot treat systemic infection.
FDA-approved for
- Clostridioides difficile-associated diarrhea (2011)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| C. difficile-associated diarrhea | adult | 200 mg BID | 200 mg BID x 10 days |
Renal Undefined
Hepatic Undefined
Instructions
- Take orally with or without food.
Available strengths
- tab 200 mg
- susp 40 mg/mL
Cautions
- Hypersensitivity reactions (angioedema, dyspnea, pruritus, rash) — possible with macrolide allergy
- Not for systemic infections — use only for C. difficile-associated diarrhea
- Development of drug-resistant bacteria if used without confirmed C. difficile
Adverse reactions
- Nausea
- Vomiting
- Abdominal pain
- GI hemorrhage
- Anemia
- Neutropenia
Pregnancy Limited data insufficient; no fetal harm in animal studies.
Lactation No data; minimal systemic absorption.
Cost
| Strength | #/mo | generic $ | CostPlus | |
|---|---|---|---|---|
| 200 mg | tab | 60 BID | $5,430.28/mo | offered |
| 40 mg/mL | susp | per unit | not offered |
Generic entry2024
NO BOXED WARNINGS
Principal riskCost; it treats nothing systemic
Classes and tags
Clinical profile
Legacy pregnancy categoryUnknown / historical label unavailable
Defining liabilityLocal irritation, sensitization or administration-site injury; negligible systemic toxicity at usual use.