Sulfasymazine is from 2 to 10 times more potent than sulfisoxazole on a dosage basis. Sulfasymazine potency ranges from 0.3 to 1 on a blood level basis. In acute toxicity studies in mice, the sodium salt of Sulfasymazine is tolerated at 2000 mg/kg orally, and at 1000 mg/kg intraperitoneally [1].