Fidaxomicin

Indications

Fidaxomicin is used for: Clostridium difficile-associated diarrhoea and colitis

Adult Dose

Oral Clostridium difficile-associated diarrhoea and colitis Adult: 200 mg bid for 10 days. Hepatic Impairment Not studied; dose adjustment not necessary since minimally absorbed

Child Dose

<18 years: Safety and efficacy not established

Renal Dose

Renal Impairment Dose adjustment not necessary

Administration

May be taken with or without food.

Contra Indications

Hypersensitivity.

Precautions

Patient w/ severe C. difficile infection, inflammatory bowel disease (e.g. ulcerative colitis or Crohn’s disease, toxic megacolon), known macrolide allergy. Not indicated for systemic infections. Moderate to severe hepatic and severe renal impairment. Pregnancy and lactation.

Pregnancy-Lactation

Pregnancy The limited available data in pregnant women are insufficient to inform any drug-associated risk for major birth defects; miscarriage or adverse maternal or fetal outcomes Animal data Embryo-fetal reproduction studies in rats and rabbits dosed intravenously during organogenesis revealed no evidence of harm to fetus at exposures 65-fold or higher than the clinical exposure at the recommended dose Lactation There is no information on presence of fidaxomicin or its main metabolite, OP-1118, in human milk, the effects on breastfed infant, or on milk production; developmental and health benefits of breastfeeding should be considered along with mother’s clinical need for therapy and any potential adverse effects on breastfed infant from therapy or from the underlying maternal condition

Interactions

May diminish the therapeutic effect of Na picosulfate, lactobacillus and estriol. May increase serum concentration of mizolastine. Increased plasma concentration w/ P-gp inhibitor (e.g. ciclosporin).

Adverse Effects

Side effects of Fidaxomicin : >10% Nausea (11%) 1-10% Vomiting (7%) Abdominal pain (6%) Gastrointestinal hemorrhage (4%) Anemia (2%) Neutropenia (2%) <1% Increased alkaline phosphatase Decreased blood bicarbonate Drug eruption Increased hepatic enzymes Megacolon

Mechanism of Action

Fidaxomicin is a macrocyclic antibiotic. It inhibits Clostridium difficile through inhibition of RNA synthesis by binding to RNA polymerase sigma subunit.