What are the side effects of sulfadiazine?

There are many side effects related to the use of sulfadiazine and they range from mild to severe. Mild side effects include: dizziness, headaches, loss of appetite, gas, upset stomach, sensitivity to sunlight, vomiting and diarrhea. An extreme allergic reaction to sulfadiazine could include: trouble swallowing, swelling of the lips and tongue, difficulty breathing, hives or rash, and requires immediate medical assistance. Sulfadiazine can also cause severe side effects, such as ringing in the ears; irregular bleeding or bruising; pale skin; irregular heartbeat; fainting; seizures; vaginal pain and discharge; blood in the urine or feces; weakness; tiredness; a yellow or blue tint to the skin or eyes; joint or muscle pain; and headaches, fever and sore throat. If you are experiencing any of these severe symptoms or if your milder symptoms worsen, contact your doctor right away.