Abstract: Formulations of pharmaceutically-acceptable salts of thienyl-, furyl- and pyrrolyl-sulfonamides and methods for modulating or altering the activity of the endothelin family of peptides using the formulations are provided. In particular, formulations of sodium salts of N-(isoxazolyl)-thienylsulfonamides, N-(isoxazolyl)furylsulfonamides and N-(isoxazolyl)-pyrrolylsulfonamides and methods using these sulfonamide salts for inhibiting the binding of an endothelin peptide to an endothelin receptor by contacting the receptor with the sulfonamide salt are provided. Methods for treating endothelin-mediated disorders by administering effective amounts of one or more of these sulfonamide salts or prodrugs thereof that inhibit or increase the activity of endothelin are also provided.