Dificlir Side Effects (Fidaxomicin)

A new drug, Dificlir (generic: fidaxomicin), will soon be available in the United Kingdom to combat clostridium difficile infection. Normally, the c. diff bacterium which is found in the stomach does not cause any problems but it can turn toxic if it multiplies faster than the “good” bacteria in the gut resulting in health problems such as diarrhea or fever.

Anyhoo, as we were saying, Dificlir is now available to fight the infection.

What are the health side effects of Dificlir? According to the prescribing information for the drug, the most common side effects of the drug (occuring in ≥ 1/100 to < 1/10 test subjects) are vomiting, nausea, and constipation. Less common side effects (≥ 1/1,000 to < 1/100) are: decreased appetite, dizziness, headache, dysgeusia, abdominal distension, flatulence, dry mouth, and increased alanine aminotransferase.

Moreover, a patient can be allergic to fidamoxicin or any of the other ingredients in the drug so Dificlir must not be used in people who are hypersensitive to said ingredients.

Warnings and precautions for users. The European Medicines Agency (EMA) released the following special warnings and precautions for use after its Committee for Medicinal Products for Human Use (CHMP) granted the pharma/manufacturer its license to market the drug:

  • Due to limited clinical data, fidaxomicin should be used with caution in patients with severe renal impairment or moderate to severe hepatic impairment (see section 5.2).
  • Due to limited clinical data, fidaxomicin should be used with caution in patients with pseudomembranous colitis, fulminant or life threatening CDI.
  • There are no data in patients with concomitant inflammatory bowel disease. Fidaxomicin should be used with caution in these patients due to the risk of enhanced absorption and potential risk of systemic adverse reactions.
  • Co-administration of potent P-glycoprotein inhibitors such as cyclosporine, ketoconazole, erythromycin, clarithromycin, verapamil, dronedarone and amiodarone is not recommended (see sections 4.5 and 5.2).

Does Dificlir affect pregnant women or nursing moms? The EMA has the answer for you. Okay, maybe they’re actually non-answers because “no data available” or “unknown” ain’t reassuring 100%. Anyhoo, here’s what the EMA says about the matter:

Pregnancy. There are no data available from the use of fidaxomicin in pregnant women. Animal studies did not indicate direct or indirect harmful effects with respect to reproductive toxicity. As a precautionary measure, it is preferable to avoid the use of DIFICLIR during pregnancy.

Breast-feeding. It is unknown whether fidaxomicin and its metabolites are excreted in human milk. Although no effects on the breastfed newborns/infants are anticipated since the systemic exposure to fidaxomicin is low, a risk to the newborns/infants cannot be excluded. A decision must be made whether to discontinue breast-feeding or to discontinue/abstain from DIFICLIR therapy, taking into account the benefit of breast feeding for the child and the benefit of therapy for the woman.

Fertility. Fidaxomicin had no effects on fertility when evaluated in rats.