- Antibiotic, Macrolide
Dosing: Geriatric Refer to adult dosing.
Dosing: Renal Impairment Minimal systemic absorption; no dosage adjustment needed
Dosing: Hepatic Impairment Not studied; minimally absorbed, so no dosage adjustment predicted
Generic Equivalent Available: U.S. No
Administration May be administered with or without food.
Use Treatment of Clostridium difficile-associated diarrhea (CDAD)
Adverse Reactions Significant >10%:
Gastrointestinal: Nausea (11%)
2% to 10%:
Gastrointestinal: Gastrointestinal hemorrhage (4%), abdominal pain, vomiting
Hematologic: Anemia (2%), neutropenia (2%)
<2%: Abdominal distension, abdominal tenderness, alkaline phosphatase increased, blood bicarbonate decreased, drug eruption, dyspepsia, dysphagia, flatulence, hepatic enzymes increased, hyperglycemia, intestinal obstruction, megacolon, metabolic acidosis, platelet count decreased, pruritus, rash
Contraindications There are no contraindications listed in the manufacturer's labeling.
Warnings/Precautions Other warnings/precautions:
• Appropriate use: Do not use for systemic infections; fidaxomicin systemic absorption is negligible. Use only in patients with proven or strongly suspected Clostridium difficile (C. difficile) infections.
Pregnancy Implications Adverse events were not observed in animal reproduction studies. Due to the limited oral absorption of fidaxomicin, exposure to the fetus is expected to be low. There are no adequate and well-controlled studies in pregnant women.
Lactation Excretion in breast milk unknown/use caution
Dietary Considerations May be taken without regard to food.
Mechanism of Action Inhibits RNA polymerase sigma subunit resulting in inhibition of protein synthesis and cell death in susceptible organisms including C. difficile; bactericidal
Pharmacodynamics/Kinetics Absorption: Oral: Minimal systemic absorption
Distribution: Largely confined to the gastrointestinal tract; in single- and multiple-dose studies, fecal concentrations of fidaxomicin and its active metabolite (OP-1118) are very high while serum concentrations are minimally detectable to undetectable
Metabolism: Intestinal hydrolysis to less active metabolite (OP-1118)
Excretion: Feces (>92% as unchanged drug and metabolites); urine (<1% as metabolite)
Product Availability Dificid™: FDA approved May 2011; expected availability third quarter 2011; consult prescribing information for additional information