<prompt> A competitive antagonist is a substance thatInteracts with receptors and produces submaximal effectBinds to the same receptor site and progressively inhibits the agonist responseBinds to the nonspecific sites of tissueBinds to one receptor subtype as an agonist and to another as an antagonist  <response>: In the presence of a fixed concentration of agonist, increasing concentrations of a competitive antagonist progressively inhibit the agonist responseBasic and clinical pharmacology Katzung 13th edition pg 23 