fidaxomicin: prescribing and clinical use
Focused clinical detail for use alongside current product information, local policy and patient-specific assessment.
fidaxomicin: clinical details
Prescribing considerations
- Confirm that the presentation is compatible with C. difficile infection and use within antimicrobial-stewardship arrangements.
- Use caution with known macrolide allergy because some hypersensitivity cases occurred in people with this history.
- Clinical experience is limited in severe renal impairment, moderate-to-severe hepatic impairment, pseudomembranous colitis and fulminant or life-threatening infection.
- Review potent P-glycoprotein inhibitors and sensitive intestinal P-glycoprotein substrates before prescribing.
- Experience is particularly limited in infants younger than 6 months and those weighing under 4 kg.
Contraindications and cautions
- Hypersensitivity to fidaxomicin or any excipient in the selected product.
Monitoring
- Monitor stool frequency, hydration, abdominal findings and overall clinical response.
- Reassess promptly if symptoms worsen, fail to improve or return after treatment.
- Monitor for hypersensitivity, particularly in people with a macrolide-allergy history.
Clinical pharmacology
Fidaxomicin is a locally acting, bactericidal macrocyclic antibacterial. It inhibits C. difficile RNA polymerase, is minimally absorbed, undergoes non-CYP formation of the active metabolite OP-1118 and is eliminated predominantly in faeces.
Formulation and product differences
- Film-coated tablets should be swallowed whole and are licensed for patients weighing at least 12.5 kg.
- The oral suspension is licensed from birth and may suit children or adults unable to swallow tablets safely.
- The suspension must be reconstituted by a healthcare professional, refrigerated after preparation and shaken before measurement.
- The oral suspension is licensed for compatible enteral feeding tubes. Crushing tablets is off-label and should follow specialist pharmacy guidance when the licensed suspension is unsuitable or unavailable.
- The suspension contains sodium benzoate, which may increase jaundice in newborn babies up to 4 weeks old.
fidaxomicin preparations and strengths
Oral suspension
Route: Oral
Strengths: 40 mg/mL
Tablet
Route: Oral
Strengths: 200 mg
fidaxomicin interactions
Clinically relevant interactions mainly involve the P-glycoprotein transporter.
Potent P-glycoprotein inhibitors, including ciclosporin, ketoconazole, erythromycin, clarithromycin, verapamil, dronedarone and amiodarone
These can increase exposure to fidaxomicin and its active metabolite. Combined use is not recommended unless specifically reviewed by the prescriber.
Dabigatran etexilate
Fidaxomicin may increase intestinal absorption of this anticoagulant, so the combination requires clinical review.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.