In mild cases Discontinuation of the offending antibiotic is usually sufficient to resolve symptoms.
Oddly enough, this disorder which is commonly caused by antibiotics is also faught with antibiotics,
narrow-spectrum antibiotics, such as metronidazole (Flagyl) and vancomycin HCl (Vancocin, Vancoled), rarely cause diarrhea;
therefore, these two antibiotics are the drugs of choice
When either metronidazole or vancomycin is used to treat antibiotic-associated diarrhea, the diarrhea
resolves within 10 days of initiating therapy in 96% of the cases.1 However, 25% of patients relapse when the antibiotic is
stopped.
Metronidazole is preferred over vancomycin because it can be given orally or parenterally, is
less expensive, and, unlike vancomycin, isn't associated with the development of resistant strains of enteric bacteria. In
patients unable to tolerate oral medication, intravenous metronidazole is the drug of choice because it is excreted in the
intestine.
Vancomycin is given orally. When given IV, the drug won't reach concentrations high enough to
eradicate C. difficile from the gut. Because vancomycin is poorly absorbed in the gut, it has few side effects and is, therefore,
the drug of choice for treating in pregnant women and children under 10.
Other antibiotics that can be used are bacitracin, teicoplanin and fusidic acid. Each are highly
effective (approximately 93% to 94%) in resolving symptom of the disease. However, each antibiotic is associated with a high
relapse rate upon discontinuation
Relapse rates
- metronidazole 16%
- vancomycin 16%
- teicoplanin 7%
- fusidic acid 28%
Recurrent or relapsing C difficile-associated colitis is not due to the development of antibiotic
resistance, and it usually resolves with a second course of one of the antibiotics recommended above. Some patients require
multiple repeat courses of antibiotic. The prognosis for full recovery in previously healthy people with C difficile is excellent.
A vaccine
Acambis is a leading developer of vaccines to prevent and treat infectious diseases. Recognized
internationally as the leading producer of smallpox vaccines, Acambis, located in the UK announces that it started a Phase
I clinical trial of its investigational vaccine against Clostridium difficile. The Phase I trial is designed to obtain information
on the safety, tolerability and immunogenicity of Acambis' C. difficile vaccine when administered at different dose levels.
The randomized, double-blind, placebo-controlled study in healthy adult subjects is being conducted at two study centers in
the US. Acambis also plans to start a second Phase I trial of its C. difficile vaccine in elderly subjects.
Acambis has been developing a C. difficile vaccine for many years and has spent the last two years
improving and optimizing the formulation of the vaccine. During that time, it has also developed an efficient manufacturing
process to produce the vaccine at its own facility.
Today, no vaccine exists to protect individuals against C. difficile and Acambis is the only company
known to be developing a vaccine against it. Its investigational toxoid vaccine was developed to provide immunity against
toxins A and B, the toxins responsible for the development of C. difficile-associated diarrhoea.
