Phthalylsulfathiazole belongs to the group of drugs called sulfonamides. The drug is a broad spectrum antimicrobial that can treat different types of infections including intestinal. The mechanism of action depends is based on competitive antagonism with para-aminobenzoic acid and inhibition of dihydropteroate synthetase activity, that in turn leads to impaired synthesis of dihydrofolic acid and as a result its active metabolite that is necessary for the synthesis of purine and pyrimidine.
The drug is indicated in treatment of dysentery, colitis, gastroenteritis and intestinal surgery. Adverse effects may include allergic reactions, vitamin B insufficiency, agranulocytosis and aplastic anemia.