Fidaxomicin

Oral
Clostridium difficile-associated diarrhoea

May be taken with or without food.

Hypersensitivity.

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.

Significant: Hypersensitivity reactions (e.g. dyspnoea, pruritus, rash, angioedema of mouth, face and throat).
Nervous: Dizziness, headache.
GI: Nausea, GI haemorrhage, abdominal pain, vomiting, abdominal distention, tenderness, dyspepsia, dysphagia, flatulence, intestinal obstruction, megacolon, anorexia, dysgeusia, constipation.
Hepatic: Increased ALT.
Haematologic: Anaemia, neutropenia.

PO: B

Monitor for signs and symptoms of hypersensitivity.

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).

Description:
Mechanism of Action: Fidaxomicin is a macrocyclic antibiotic. It inhibits Clostridium difficile through inhibition of RNA synthesis by binding to RNA polymerase sigma subunit.
Pharmacokinetics:
Absorption: Poorly absorbed from the GI tract. Time to peak plasma concentration: 1.75 hr.
Distribution: Largely confined to the GI tract.
Metabolism: Undergoes intestinal metabolism via hydrolysis to less active metabolite (OP-1118).
Excretion: Mainly via faeces (>92% as unchanged drug and metabolites); urine (<1% as metabolite). Elimination half-life: Approx 12 hr (fidaxomicin); approx 11 hr (OP-1118).

Source: National Center for Biotechnology Information. PubChem Database. Dificid, CID=10034073, https://pubchem.ncbi.nlm.nih.gov/compound/Dificid (accessed on Jan. 21, 2020)

Store between 20-25°C.

Macrolides

Anon. Fidaxomicin. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 05/09/2017.

Buckingham R (ed). Fidaxomicin. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 05/09/2017.

Dificid Tablet, Film Coated (Merck Sharp & Dohme Corp.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 05/09/2017.

Joint Formulary Committee. Fidaxomicin. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 05/09/2017.

McEvoy GK, Snow EK, Miller J et al (eds). Fidaxomicin. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 05/09/2017.