Because CDI is frequently seen in individuals taking antibiotic medications to treat other infections, it is important to stop taking all antibiotics other than those prescribed by the doctor to treat CDI (the doctor will explain which antibiotics to take and which to stop). This is because taking other antibiotics at the same time as those used to treat CDI can reduce the effectiveness of the antibiotics used for CDI.

The following antibiotics are typically used for the treatment of a an initial CDI:

  • For a patient with mild to moderate CDI, the antibiotic Flagyl® (metronidazole) is given at a dose of 500 milligrams 3 times daily by mouth for 10 to 14 days
  • For a patient with severe CDI, the antibiotic Vancocin® (vancomycin) is given at a dose of 125 milligrams 4 times daily by mouth for 10 to 14 days
  • If a patient has severe CDI and additional symptoms such as shock and other digestive issues are also present, the dose of vancomycin is increased to 500 milligrams 4 times daily given by mouth or by a tube inserted into the stomach through the nose. In addition, metronidazole is given as an injection at a dose of 500 milligrams every 8 hours. If the patient has an intestinal blockage, it may be necessary to give vancomycin through the rectum

The following antibiotics are typically given for patients with a recurrent CDI:

  • If CDI occurs a second time, the same antibiotics used for the first infection are usually given
  • If CDI occurs a third time, vancomycin is recommended at an initial higher dose and is gradually decreased over several days. Another option is vancomycin given at the same dose over several days, but with gaps in between (also known as a “pulsed” treatment)

In 2011, the antibiotic Dificid® (fidaxomicin) was approved for use in the United States. This antibiotic works by killing the C. diff bacteria rather than just slowing down its growth, and it specifically kills C. diff bacteria to a greater extent than the other “good” bacteria. Fidaxomicin stays in the gastrointestinal tract and very little is absorbed into the blood, so it is less likely to cause side effects. Treatment of CDI with fidaxomicin has been shown to result in lower rates of repeat infection. However, fidaxomicin can cause nausea and vomiting and other gastrointestinal side effects. Some patients have also had low red and white blood cell counts after taking this drug.

Fidaxomicin is more expensive than metronidazole and vancomycin. Because of this, the insurance provider may only cover the cost of this antibiotic in certain circumstances (for example, if someone has recurrent CDI even after treatment with metronidazole or vancomycin). If a patient has recurrent CDI, they should speak with their doctor to see if fidaxomicin may be right for them.

Other Treatments

The following non-antibiotic options are available for the treatment of CDI:

  • Intravenous immunoglobulin (also called IVIG), a substance that contains antitoxins (substances that act against diff), has been used to treat some cases of CDI. However, this treatment has many side effects and may not be beneficial in adults, although there is some evidence that it is effective in children
  • Fecal transplant, or fecal microbiota transplantation (FMT), is a process in which fecal matter, or stool sample, from a healthy donor is collected, strained, mixed with a sterile salt solution, and placed in a patient with CDI. This is usually performed by a process called colonoscopy, in which a flexible tube is passed thorough the anus and rectum. Several studies have shown that FMT is effective in treating patients with recurrent CDIs. Visit our sister organization, The Fecal Transplant Foundation, to learn more
  • Another option is probiotics, which are live bacteria that do not cause disease but are capable of replacing the “good” bacteria that have been killed by diff. Although a recent study has shown that use of probiotics in adults reduced the risk of CDI, additional data are needed before they can be recommended for CDI
  • In patients with severe cases, surgery to remove the infected part of the colon might be required. The Centers for Disease Control and Prevention report that surgery is needed in only 1 or 2 of every 100 persons with a CDI

What Treatment Options Are Expected in the Future?

Continued efforts are being made to develop new treatment options for CDI, including:

  • Antibiotics such as surotomycin and cadazolid, which are being studied to see how well they can treat CDI
  • Vaccines (such as PF-06425090, VLA84, and ACAM-CDIFF™) in development by multiple companies are being tested for their ability to prevent (rather than treat) CDI
  • Substances called antibodies, which prevent diff from causing any symptoms by binding to the toxins that cause these symptoms, are also being studied. Two antibodies named MK-6072 and MK-3415A are currently being tested
  • A modified type of diff bacteria called VP20621, which does not cause any symptoms because it does not produce toxins, is being tested for its ability to prevent repeated CDIs. The expectation is that this modified C. diff bacteria will be given by mouth as a liquid. Once ingested, it can establish itself in the patient’s gut and prevent the disease-causing C. diff bacteria from infecting the patient

Some of these new treatment options that are being tested will hopefully get approval from the US Food and Drug Administration (FDA) and will assist doctors in successfully preventing and treating CDIs, which can be quite devastating for both patients and their families.