Mechanism of action for DIFICID® (fidaxomicin)

• DIFICID is contraindicated in patients who have known hypersensitivity to fidaxomicin or any other ingredient in DIFICID.
• Acute hypersensitivity reactions, including dyspnea, rash, pruritus, and angioedema of the mouth, throat, and face have been reported with DIFICID. If a severe hypersensitivity reaction occurs, DIFICID should be discontinued and appropriate therapy should be instituted.
• DIFICID is not expected to be effective for the treatment of other types of infections due to minimal systemic absorption of fidaxomicin. DIFICID has not been studied for the treatment of infections other than CDAD. DIFICID should only be used for the treatment of CDAD.
• Only use DIFICID for infection proven or strongly suspected to be caused by C. difficile. Prescribing DIFICID in the absence of a proven or strongly suspected C. difficile infection is unlikely to provide benefit to the patient and increases the risk of development of drug-resistant bacteria.
• The most common adverse reactions in adults reported in clinical trials are nausea (11%), vomiting (7%), abdominal pain (6%), gastrointestinal hemorrhage (4%), anemia (2%), and neutropenia (2%).
• Among adult patients receiving DIFICID, 33 (5.9%) withdrew from trials as a result of adverse reactions. Vomiting was the primary adverse reaction leading to discontinuation of dosing (incidence of 0.5% for both DIFICID and vancomycin patients).
• The most common adverse reactions in pediatric patients treated with DIFICID are pyrexia (13.3%), abdominal pain (8.2%), vomiting (7.1%), diarrhea (7.1%), constipation (5.1%), increased aminotransferases (5.1%), and rash (5.1%).
• The safety and effectiveness of DIFICID in patients <6 months of age have not been established.
• The recommended dose of DIFICID for adults and pediatric patients weighing at least 12.5 kg and able to swallow tablets is one 200 mg tablet orally twice daily for 10 days, with or without food. The recommended weight-based dosage of the oral suspension in pediatric patients (weighing at least 4 kg) is twice daily for 10 days.
• No dose adjustment is recommended for patients ≥65 years of age.
• No dose adjustment is recommended for patients with renal impairment.
• No dosage adjustments are recommended when co-administering fidaxomicin with substrates of P-gp or CYP enzymes.
• The impact of hepatic impairment on the pharmacokinetics of fidaxomicin has not been evaluated; however, because fidaxomicin and its active metabolite (OP-1118) do not appear to undergo significant hepatic metabolism, elimination of fidaxomicin and OP-1118 is not expected to be significantly affected by hepatic impairment.

Before prescribing DIFICID® (fidaxomicin), please read the Prescribing information. The Patient information also is available.