Sulfadimethoxine is an antibiotic and also used to treat coccidial infections in many species. 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, or skin rashes 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.