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.

McGraw-Hill Nurse's Drug Handbook, 7th Ed. Copyright © 2013 by The McGraw-Hill Companies, Inc. All rights reserved


(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.
Drug Guide, © 2015 Farlex and Partners
References in periodicals archive ?
The global market for Macrolide Antibiotics is segmented on the basis of Treatment Type, End User and geography: Macrolide Antibiotics Market Segment by Drug Type Azithromycin Clarithromycin Erythromycin Fidaxomicin Telithromycin Request Free Sample Report@ Macrolide Antibiotics Market Segment by Route of Administration Oral Parenteral Macrolide Antibiotics Market Segment by Distribution Channel Hospital Pharmacy Retail Pharmacy Mail Order Pharmacy The global Macrolide Antibiotics market is segmented by drug type, route of administration, distribution channel and geography.
* In July 2017, filed an application for marketing approval in Japan with regard to fidaxomicin for the treatment of infectious enteritis.
Treatment is to stop the antibiotics and start treatment with two others - vancomycin and fidaxomicin. Unfortunately, about half of treated patients will get it again and faecal transplantation may be considered necessary.
It has demonstrated significant efficacy and superiority to reference treatments (fidaxomicin in particular) against isolates of C.
For example, based on evidence from clinical trials, advocacy of the previous first-line treatment, metronidazole, has been replaced with a strong preference for vancomycin or fidaxomicin, delivered for ten days for mild or moderate cases in adults.
Gorbach, "Resolution of Clostridium difficile-associated diarrhea in patients with cancer treated with fidaxomicin or vancomycin," Journal of Clinical Oncology, vol.
Treatment of CDI with antibiotics (metronidazole, vancomycin, or fidaxomicin) is frequently complicated by recurrence, further raising disease burden.
Use of other, expensive, antibiotic treatments including Fidaxomicin is not effective against the BI/NAP1/027 strain.
SAN FRANCISCO--The role of fidaxomicin for treating mild to moderate Clostridium difficile infection is still finding its way, according to Sarah Doernberg, MD.
No information could be gathered regarding treatment with fidaxomicin since at present time its distribution is not approved in Mexico.