From Pharmacy Drug Guide
In, 2011, the FDA approved fidaxomicin (Dificid®) exclusively for the treatment of C. difficile (Clostridium difficile, or C. diff). C. diff is a bacterium which causes diarrhea, colitis and other infections that can be life-threatening, often in older adults in hospitals or nursing homes. The infection does not normally affect healthy people, but may affect those with an illness that necessitates long-term antibiotic use. Common symptoms of C. diff include frequent diarrhea for several days, fever, reduced appetite, upset stomach and abdominal cramping. Until the approval of fidaxomicin, C. diff was often treated with vancomycin.
Fidaxomicin is an orally-administered prescription antibacterial medication. Because it remains in the gastrointestinal tract and is not absorbed throughout the body, fidaxomicin is recommended only for the treatment of C. diff and is not effective in the treatment of systemic infections. The most common side effects of fidaxomicin are nausea, vomiting, and abdominal pain.
|Manufacturer||Optimer Pharmaceuticals, Inc.|
|Uses||Used to treat Clostridium difficile infections.|
|Common side effects||Nausea, vomiting, and abdominal pain.|
|Major side effects||Gastrointestinal hemorrhage, anemia (loss of red blood cells), and neutropenia (loss of certain white blood cells.)|
|Warnings||Fidaxomicin should only be used to treat C. diff infections, in order to reduce the development of drug resistant bacteria. Fidaxomicin should be used in pregnant women and nursing mothers only if clearly needed.|
|Disclaimer||The information provided by PharmacyDrugGuide.com is not a substitute for professional medical advice, diagnosis, or treatment. Do not take any action based on the information on this page without consulting a physician.|
Unlike vancomycin, fidaxomicin is a narrow spectrum antibiotic, effective against C. diff while not damaging the bacteria normally found in the gastrointestinal tract. For this reason, reinfection is less likely than when vancomycin is used. C. diff is usually found in older adults in hospitals and nursing homes, when those patients have completed courses of antibiotics which have damaged the bacteria found in the gastrointestinal tract. Patients who lack these healthy bacteria sometimes become infected with C. diff, which is difficult to control and eliminate.
Fidaxomicin targets C. diff bacteria while sparing other bacteria, giving the patient some protection against reinfection.  Because bacteria are able to adapt to antibacterial medications, especially when those medications are used incorrectly or inappropriately, fidaxomicin is only indicated for known or strongly suspected C. diff infections.
Fidaxomicin is an antibiotic, and is not commonly abused. While no known human fidaxomicin overdoses have been recorded, animal tests showed no adverse effects when doses greater than 100 times the human dose were administered. Fidaxomicin is not meant to be used for any other type of infection besides C.diff, or else there is danger of the drug losing effectiveness or the bacteria becoming antibiotic-resistant.
Fidaxomicin Side Effects
Common side effects of fidaxomicin include nausea, vomiting, and abdominal pain. Some of these adverse effects may improve if fidaxomicin is taken with food. More serious side effects may include gastrointestinal hemorrhage, anemia (loss of red blood cells), and neutropenia (loss of certain white blood cells). These side effects may require medical attention.