Radiopaque agent: Acetrizoic acid (trade names Gastrografina, Urografina in Portugal) is a palatable lemon-flavored water-soluble iodinated radiopaque X-ray contrast medium for oral or rectal administration only. Acetrizoic acid is indicated for radiographic examination of segments of the gastrointestinal tract (esophagus, stomach, proximal small intestine, and colon). The preparation is particularly indicated when a more viscous agent such as barium sulfate, which is not water-soluble, is not feasible or is potentially dangerous. Administration of hypertonic Gastrografin solutions may lead to hypovolemia and hypotension due to fluid loss from the intestine.