Sulfadimethoxine/ormetoprim is a potentiated sulfa drug used to treat infected wounds and susceptible bacterial infections of the skin and urinary tract. Consult your veterinarian if your pet experiences discharge from the eye, redness of the eye, other symptoms related to the eye, pale gums, bleeding tendencies, vomiting, diarrhea, joint pain, increased thirst, skin rashes, facial swelling, staggering, or behavior changes while being treated with sulfadimethoxine. The pet should be encouraged to drink a lot of water while being treated with sulfadimethoxine to prevent crystals from forming in the urine. Use all of the medication prescribed, or the infection is likely to recur or become worse.