This combination can cause a drop in white blood cells, and kidney problems. Also, sulfadiazine is a sulfa drug. Almost half the people who take it have an allergic reaction. This usually is a skin rash, sometimes a fever. Allergic reactions can be overcome using a desensitization procedure.
Patients start with a very small amount of the drug.
They get increasing amounts until they can tolerate the full dose. You can be tested to see if you have been exposed to toxo. If not, you can reduce your risk of infection by not eating undercooked meat or fish, and by wearing gloves and a face mask and washing thoroughly if you clean a cat box. If you have less than 100 T-cells, you should take medication to prevent toxo. These drugs also protect you against toxo.