Sulfisoxazole (gantrisin\s=r\),3,4-dimethyl-5-sulfanilamido-isoxazole, introduced in 1946, is widely used in treatment of bacterial infections, especially those of the urinary tract. The drug is said to be one of the safest of the sulfonamides. It is described by the manufacturer as a "single drug\p=m-\not a mixture of several sulfonamides\p=m-\ so that there is less likelihood of sensitization" and as "having greater solubility and higher blood-levels."