Pharmacologic class: Macrolide

Therapeutic class: Anti-infective

Pregnancy risk category B


Bactericidal against Clostridium difficile in vitro, inhibiting RNA synthesis by RNA polymerases


Tablets: 200 mg

Indications and dosages

C. difficile-associated diarrhea

Adults: 200-mg tablet P.O. b.i.d. for 10 days




Use cautiously in:
• systemic infections or absence of proven or strongly suspected C. difficile infection
• pregnant or breastfeeding patients
• children younger than age 18 (safety and efficacy not established).


• Administer with or without food.
• Be aware that using drug in absence of proven or strongly suspected C. difficile infection is unlikely to provide benefit to patient and increases risk of development of drug-resistant bacteria.
• Be aware that drug has minimal systemic absorption and isn't effective in treatment of systemic infections.

Adverse reactions

GI: nausea, vomiting, abdominal pain, GI hemorrhage

Hematologic: anemia, neutropenia


Drug-drug.Cyclosporine: increased plasma concentrations of fidaxomicin and its metabolite

Patient monitoring

• Monitor CBC periodically.
• Observe patient for signs and symptoms of GI hemorrhage.

Patient teaching

• Tell patient to take drug with or without food.
• Inform patient that drug only treats C. difficile-associated diarrhea and shouldn't be used to treat other infections.
• Inform patient that although it's common to feel better early in the course of therapy, the drug should be taken exactly as directed. Skipping doses or not completing full course of therapy may decrease effectiveness of immediate treatment and increase likelihood that bacteria will develop resistance and won't be treatable by this drug or other antibacterials in the future.

Instruct patient to promptly report signs and symptoms of GI bleeding.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs mentioned above.


(fi-dax-oh-mye-sin) ,


(trade name)


Therapeutic: anti infectives
Pharmacologic: macrolides
Pregnancy Category: B


Treatment of diarrhea associated with Clostridium difficile.


Bactericial action mostly against clostridia; inhibits RNA synthesis.
Acts locally in the GI tract to eliminate Clostridium difficile.

Therapeutic effects

Elimination of diarrhea caused by Clostridium difficile.


Absorption: Minimal systemic absorption.
Distribution: Stays primarily in the GI tract.
Metabolism and Excretion: Mostly transformed via hydrolysis in the GI tract to OP-1118, its active metabolite. Eliminated mostly (>92%) in feces: <1% excreted in urine.
Half-life: Fidaxomicin—11.7 hr; OP-1118—11.2 hr.

Time/action profile



Contraindicated in: Hypersensitivity.
Use Cautiously in: Obstetric / Lactation: Use during pregnancy only if clearly needed, use cautiously during lactation; Pediatric: Safe and effective use in children <18 yr has not been established.

Adverse Reactions/Side Effects


  • GI hemorrhage (life-threatening)
  • nausea (most frequent)
  • abdominal pain


  • anemia
  • neutropenia


  • hypersensitivity reactions (life-threatening)


Drug-Drug interaction

No significant interactions noted.


Oral (Adults >18 yr) 200 mg twice daily for 10 days.


Tablets: 200 mg

Nursing implications

Nursing assessment

  • Monitor bowel function for diarrhea, abdominal cramping, fever, and bloody stools. May begin up to several weeks following cessation of antibiotic therapy.
  • Monitor for signs and symptoms of hypersensitivity reactions (dyspnea, pruritus, rash, angioedema of mouth, throat, and face) periodically during therapy. Risk increases with a macrolide allergy.
  • Lab Test Considerations: May cause ↑ serum alkaline phosphatase, and hepatic enzymes.
    • May cause ↓ serum bicarbonate, ↓ platelet count, anemia, and neutropenia.
    • May cause hyperglycemia and metabolic acidosis.

Potential Nursing Diagnoses

Risk for infection (Indications)
Diarrhea (Indications)


  • Oral: Administer twice daily without regard to food.

Patient/Family Teaching

  • Instruct patient to take fidamoxicin as directed for the full course of therapy, even if feeling better. Skipping doses or not completing full course of therapy may decrease effectiveness of therapy and increase risk that bacteria will develop resistance and not be treatable in the future.
  • Advise female patients to notify health care professional if pregnancy is planned or suspected or if breast feeding.

Evaluation/Desired Outcomes

  • Decrease in diarrhea caused by Clostridium difficile.
References in periodicals archive ?
The study, conducted at St George's Hospital in London, England, is the first of its kind and looks at a year's experience using fidaxomicin as a first-line treatment for all adults confirmed to have CDI, including populations not previously studied in randomised controlled Phase III trials.
Indeed, cost is cited as a key consideration in the ongoing formulary decisions for ceftaroline (Forest/AstraZeneca's Teflaro), fidaxomicin (Optimer/Cubist's Dificid), and future assessments of Astellas/Basilea's emerging azole isavuconazole.
surotomycin - Drug Profile 35 Product Description 35 Mechanism of Action 35 R&D Progress 35 crofelemer DR - Drug Profile 36 Product Description 36 Mechanism of Action 36 R&D Progress 36 fidaxomicin - Drug Profile 38 Product Description 38 Mechanism of Action 38 R&D Progress 38 cadazolid - Drug Profile 41 Product Description 41 Mechanism of Action 41 R&D Progress 41 fidaxomicin - Drug Profile 42 Product Description 42 Mechanism of Action 42 R&D Progress 42 AKT-10081 - Drug Profile 45 Product Description 45 Mechanism of Action 45 R&D Progress 45 MGB-BP-3 - Drug Profile 46 Product Description 46
Efficacy of tapered fidaxomicin dosing regimens to treat simulated Clostridium difficile infection (CDI) in an in vitro gut model
The European Society of Clinical Microbiology and Infectious Diseases (ESCMID) has published new guidelines recommending fidaxomicin for all CDI patients suitable for oral antibiotic treatment.
However, Clinical Data and Interviewed Thought Leaders Indicate That Fidaxomicin Has Advantages Over Sales-Leading Vancocin Regarding Recurrence Rates, According to Findings from Decision Resources
Important Safety Information for DIFICID DIFICID is contraindicated in patients with hypersensitivity to fidaxomicin.
Fidaxomicin offers several advantages over the standard-of-care therapy: lower relapse rates, a targeted spectrum and less frequent dosing.
The CHMP positive opinion is based on Phase 3 clinical studies that were conducted to compare the safety and efficacy of 400mg/day fidaxomicin with 500mg/day oral vancomycin for 10 days in subjects with CDI.
to regain the rights to fidaxomicin in North America, and was partially offset by an increase in expenses related to fidaxomicin and prulifloxacin Phase 3 clinical trials in 2008.
to develop and commercialise fidaxomicin, an investigational antibiotic under regulatory review as a novel treatment for Clostridium difficile infection in Europe and certain other countries.
for the development and commercialisation in Europe and selected other countries of fidaxomicin for the treatment of clostridium difficile infection.