Are there serious side effects of probenecid?

Rarely, patients taking probenecid could have problems with their blood cells. There have been reports of people getting several kinds of blood cell disorders after taking probenecid. In aplastic anemia, the bone marrow does not make enough blood cells; all the different types of blood cells (red, white and platelets) are affected. In leukopenia, the number of white blood cells goes down, while in thrombocytopenia, the cells responsible for blood clotting (the platelets) are at abnormally low levels. Other rare but serious effects of probenecid include Stevens-Johnson syndrome, which is a potentially life-threatening skin reaction, and liver cell death. A dangerous allergic response called anaphylaxis has also happened to a few people taking probenecid.