Pentagastrin (trade name Peptavlon) is a cholecystokinin type B (CCK(B)) receptor agonist, which was indicated as a diagnostic aid for evaluation of gastric acid secretory function. It was effective in testing for an acidity (achlorhydria) in patients with suspected pernicious anemia, atrophic gastritis, or gastric carcinoma. It was effective in determining the reduction in acid output after operations for peptic ulcer, such as vagotomy or gastric resection. Pentagastrin was also indicated as a diagnostic aid in testing for gastric hypersecretion in patients with suspected duodenal ulcer or postoperative stomal ulcer, and for the diagnosis of Zollinger-Ellison tumor. Peptavlon was discontinued, Federal Register determined that product was not discontinued or withdrawn for safety or efficacy reasons. In addition was shown, that Pentagastrin may release adrenocorticotropin (ACTH) and cortisol through direct pharmacological action, perhaps enhanced on first exposure by psychologically mediated novelty effects. Novelty, per se, is not likely the primary mediator of the hypothalamic-pituitary-adrenal (HPA) response. This model may be useful for further study of cognitive-emotional modulators of HPA axis activity.

CHLORMERODRIN HG-197 is a radiolabelled form of chlormerodrin, an organomercury compound that was previously used as a diuretic. Its radiolabelled form was used as diagnostics in brain scans.

Iocetamic acid is a medical diagnostic aid. It is a contrast agent used to enhance structures or fluids during X-ray imaging.

Metrizoic acid is a diagnostic radiopaque that usually occurs as the sodium salt. The mechanism of action of metrizoic acid is as a X-Ray Contrast Activity.

Tyropanic acid and its salt sodium tyropanoate are radiocontrast agents used in cholecystography (X-ray diagnosis of gallstones). Tyropanic acid is sold under the trade names Bilopaque, Lumopaque, Tyropaque, and Bilopac. The molecule contains three heavy iodine atoms which obstruct X-rays in the same way as the calcium in bones to produce a visible image. After injection it is rapidly excreted into the bile.

Iopydone is a pyridine derivative patented by Schering-Kahlbaum A.-G. As radiographic contrast medium for bronchography. Hytrast, an aqueous suspension containing Iopydol and Iopydone has widely used in some countries. Extensive clinical trials had suggested that Hytrast was superior to products usually employed for this purpose. Hytrast provides excellent quality bronchograms with a fine dense coating of the bronchial walls and no ‘alveolar filling’.

Iopanoic acid and ipodate salts have been used for oral cholangiography to visualize the biliary ducts. Ipodate salts have been used for the long-term treatment of Graves' disease and in hyperthyroidism. Ipodate reduced levels of T3 and T4 in the patients. Ipodate also inhibits the conversion of T4 to T3. It is not considered a first-line approach. Ipodate sodium lacks FDA approval for these uses. During investigation of mechanism of action was discovered, that binding of sodium ipodate with nuclear T3 receptors was not a prominent mechanism via which the drug attenuates T3 effects in vivo. Sodium ipodate could enhance T3 effects at the cellular level and that enhancement could not be reflected by routinely monitored serum TSH.

Iopydol is an X-ray contrast medium used in conjunction with iopydone as the proprietary preparation, Hytrast, for the bronchography.

BUNAMIODYL is an cholecystographic agent which was used to aid the radiographic visualization of the gallbladder for detecting the presence of gallstones in cholelithiasis patients. It was withdrawn from the market due to nephropathy.

Diprotrizoic acid is dipropionamino compound. It is a diagnostic aid. Diprotrizoic acid was introduced for urography but it produced more side effects than diatrizoic acid.