What Is Fidaxomicin?

Physicians may prescribe fidaxomicin for the treatment of Clostridium difficile and associated diarrhea. The oral anti-infective product specifically targets the Clostridium organism. Reports indicate that fidaxomicin causes fewer of the gastrointestinal side effects commonly associated with antibiotics. Studies also suggest that fewer patients undergoing treatment with the medication experience resurgence of bacterial colonization.

Fidaxomicin belongs to a group of macrocyclic antibiotic drugs. These particular pharmaceutical drugs have a molecular structure comprised of a large macrolide ring to which one or more sugars attach. Laboratories formulate fidaxomicin by fermenting bacteria known as Dactylosporangium aurantiacum. The tablets are coated with an enteric layer, which ensures that the medication only activates after traveling to the bowel.

The medication’s mode of action involves inhibiting the enzyme required by ribonucleic acid (RNA). RNA performs intracellular functions that include protein formation and cell replication. With normal cellular activity prevented, the bacteria die. Prior to prescribing antibiotics, physicians usually order a stool culture to positively identify the specific bacteria species. Using fidaxomicin for infections other than Clostridium difficile may produce resistant strains of other bacteria species.

Minimal amounts of the medication are actually absorbed by the bowel. Most remains in the intended location. Unlike many other antibiotics, fidaxomicin does not eliminate normal flora, which can cause yeast infections. Patients generally take one 200-milligram fidaxomicin tablet, with or without food, twice a day for 10 days.

Typical side effects associated with the anti-infective include abdominal pain with possible nausea and vomiting. In rare instances, patients may suffer gastrointestinal bleeding. Some patients may experience anemia with a particular decrease in the number of neutrophils, white blood cells that are part of the immune system that fights infection.

As Clostridium difficile, or C. diff, bacteria exist naturally in the environment, healthy people commonly have the bacteria in their digestive tract. Scientists report that C. diff strains have become more drug resistant and infections more frequent and severe. Individuals with compromised immune systems, recent hospitalizations, or recent antibiotic therapy are more likely to develop an overpopulation of the bacteria.

The bacteria produce toxins that irritate the lining of the bowel, and the inflammation produces symptoms that usually begin with abdominal discomfort and watery diarrhea. Severe or life-threatening symptoms that require medical intervention include fever, bloody or pus-filled stools, and continuous watery stools throughout the day. The infection can quickly lead to dehydration, electrolyte imbalance, and weight loss.