The U.S. Food and Drug Administration today approved Dificid (fidaxomicin) tablets for the treatment of Clostridium difficile-associated diarrhea (CDAD).

Clostridium difficile (C. difficile) is a bacterium that can cause diarrhea and lead to colitis, other serious intestinal conditions, and death in severe cases. C. difficile bacteria are found in the stool of an infected person, and others can become infected if they touch items or surfaces contaminated with the bacteria or spores and then touch their mouths.

The safety and efficacy of Dificid were demonstrated in two trials that included 564 patients with CDAD that compared Dificid with vancomycin, a common antibiotic used to treat CDAD. The clinical response was similar in the Dificid group compared with the vancomycin group in both studies. In some patients with CDAD, symptoms can return. In the Dificid trials, a greater number of patients treated with Dificid had a sustained cure three weeks after treatment ended versus those patients treated with vancomycin.

“In recent years, many in the infectious disease community have seen an increase in the number of cases of people with a C. difficile infection,” said Edward Cox, M.D., M.P.H., director of the Office of Antimicrobial Products in the FDA’s Center for Drug Evaluation and Research. “Dificid is an effective new treatment option for patients who develop Clostridium difficile-associated diarrhea.”

Dificid, a macrolide antibacterial, should be taken two times a day for 10 days with or without food.

To maintain the effectiveness of Dificid, and to reduce the development of drug-resistant bacteria, the drug should be used only to treat infections that are proven or strongly suspected to be caused by C. difficile.

The most common side effects reported with Dificid included nausea, vomiting, headache, abdominal pain, and diarrhea.

People at risk of developing the bacterial infection include the elderly, patients in hospitals or nursing homes, and people taking antibiotics for another infection. The most effective way to prevent CDAD is thorough handwashing with soap and warm water.

Dificid was developed by San Diego-based Optimer Pharmaceuticals Inc.