Solving EPM

http://ourworld.compuserve.com/homepages/drfenger/

The most exciting new development in the area of EPM research is the advent of new and different alternatives for treating EPM. There are no FDA approved drugs for the treatment of this disease, but a number of drugs have been used off-label, or imported from other countries for treating EPM. The most common treatment is still a combination therapy of pyrimethamine (1.0 mg/kg daily), in combination with sulfadiazine (20 mg/kg daily), most commonly available from compounding pharmacies . This combination is protected by a patent, and current legally licensed pharmacies include Vet's Choice (888-809-3710). Horses should remain on both drugs for the duration of treatment, because protozoa have been shown to become resistant to pyrimethamine in the absence of sulfas. Trimethoprim is not recommended, and probably should be avoided, if possible, because it is likely to add to the toxicity of the pyrimethamine, without adding to the efficacy (Fenger et al., 1997, b). Beware of compounding pharmacies that compound a combination product with trimethoprim, pyrimethamine and sulfadiazine, because the trimethoprim is contraindicated. Ideally, CSF should be obtained and determined to test negative by immunoblot before the treatment is discontinued (Fenger et al., 1997, b), although this approach is likely to be extremely conservative, and many horses may actually continue to test positive for several months after the protozoa is killed.

Antiinflammatory therapy is indicated in acute EPM cases. This may include treatment with phenylbutazone or banamine (1.1 mg/kg 1-2 times daily for 3-7 days), as well as the addition of DMSO (1 g/kg in a 10% solution) administered either intravenously or by nasogastric tube. Corticosteroids may be used if necessary. Antiinflammatory drugs are occasionally necessary at other times during the first six weeks of treatment. Some horses actually get worse during treatment, presumably because of a reaction to the dying parasites (Fenger et al., 1997, b). Supplementation with vitamin E, folic acid and thiamine may be helpful adjunct treatment (Fenger et al., 1997, b). Some recent evidence has put the use of folic acid supplementation into question. However, it is probably safe and recommended for most performance horses, but not recommended for use in pregnant animals.

Thank you for visiting the EPM home page. Look for regular updates as more research becomes available. This website is under construction and should undergo many changes as my HTML literacy increases. Look for photos of cases and parasites in the future. The author is a veterinarian and a primary researcher studying EPM, not a professional computer whiz. If you have specific questions about EPM, or ideas that would improve my site, please let me know. The data maintained in this website is intended to educate horsepeople and veterinarians, and not intended to diagnose or prescribe treatment for any specific horse. The information kept here has been carefully researched, but inaccuracies may exist due to lack of information at this time, or typographical errors. Because of this, I cannot be responsible for any problems that arise as a result of the information on this website. If you have questions about a specific case, your best resource is your own veterinarian.

# posted by ChiefOptimizer @ 12:43 PM