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.

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

Methiodal is used in lumbar myelography as a contrast agent.

Propyliodone (INN, trade name Dionosil) is a molecule used as a contrast medium. It was developed by a team at Imperial Chemical Industries in the late 1930s. Propyliodone used as radiopque medium for brochographic use. When directly instilled into the bronchi resulting in well-defined bronchograms for atleast 30 min. Because of its toxicity, Propyliodone should only be used if absolutely essential. It is of Synthetic origin and belongs to Iodinated Radio-opaque Compounds. It belongs to Radiopaque Agents pharmacological group on the basis of mechanism of action and also classified in Diagnostic Aids pharmacological group. Oral absorption of Propyliodone is found to be 101% and metabolism is reported Lungs and Gut wall. Propyliodone is primarily indicated in conditions like Paget's disease of bone, Radiological contrast agent. Propyliodone produces potentially life-threatening effects which include Fever, Anaphylaxis, Repiratory obstruction, Cerebral embolization, which are responsible for the discontinuation of Propyliodone therapy. The signs and symptoms that are produced after the acute overdosage of Propyliodone include Airway obstruction. The symptomatic adverse reactions produced by Propyliodone are more or less tolerable and if they become severe, they can be treated symptomatically, these include Headache, Fever, Malaise, Nausea and vomiting, Aching joints.

Iodipamide is used as a contrast agent for cholecystography and intravenous cholangiography. Following intravenous administration of Cholografin Meglumine, iodipamide is carried to the liver where it is rapidly secreted. The contrast medium appears in the bile within 10 to 15 minutes after injection, thus permitting visualization of the hepatic and common bile ducts, even in cholecystectomized patients. Iodipamide (Cholografin Meglumine) is indicated for intravenous cholangiography and cholecystography as follows: (a) visualization of the gallbladder and biliary ducts in the differential diagnosis of acute abdominal conditions, (b) visualization of the biliary ducts, especially in patients with symptoms after cholecystectomy, and (c) visualization of the gallbladder in patients unable to take oral contrast media or to absorb contrast media from the gastrointestinal tract. The biliary ducts are readily visualized within about 25 minutes after administration, except in patients with impaired liver function. The gallbladder begins to fill within an hour after injection; maximum filling is reached after two to two and one-half hours. Organic iodine compounds block x-rays as they pass through the body, thereby allowing body structures containing iodine to be delineated in contrast to those structures that do not contain iodine. The degree of opacity produced by these iodinated organic compounds is directly proportional to the total amount (concentration and volume) of the iodinated contrast agent in the path of the x-rays. Iodipamide's primary excretion through the hepato-biliary system and concentration in bile allows visualization of the gallbladder and biliary ducts.

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.

Perflenapent (EchoGen, Sonus Pharmaceuticals, Bothel, WA, USA) is a transpulmonary echocardiographic contrast agent for use in patients with suspected or established cardiovascular disease to provide opacification of cardiac chambers, enhance left ventricular border delineation with resulting improvement in wall motion visualisation. EchoGen comprises liquid droplets of dodecafluoropentane stabilised by polyfluoroalkyl(polyoxyethylene) ethanol and dispersed in an aqueous formulation containing sucrose. Dodecafluoropentane is the chemical name used to reflect the perflenapent/perflisopent mixture. Following activation and administration of EchoGen, dodecafluoropentane microbubbles are formed. EchoGen should only be used in patients where the study without contrast enhancement is inconclusive. The European Commission has approved SONUS Pharmaceuticals' EchoGen (perflenapent emulsion) in all 15 countries of the European Union. EchoGen is a fluorocarbon-based ultrasound contrast agent which has been approved as a transpulmonary echocardiographic contrast agent for use in patients with suspected or established cardiovascular disease who have had previous inconclusive non-contrast studies. Additional approved labeling in the EU states that the use of EchoGen in spectral and color Doppler studies was shown to enhance the visualization of blood flow across mitral, aortic and tricuspid valves in a subset of patients. In 2000 SONUS Pharmaceuticals withdrew the NDA for EchoGen in the USA.

Galactose, a monosaccharide sugar, is a key source of energy and is an important compound for early human development. Galactose is present in dairy products, the pectin of some fruits, vegetables, and some herbs. Children get most of their dietary galactose from milk. D-galactose is freely available in health food stores and is promoted for stimulating the immune system and improving gut motility in healthy individuals. Galactose as a part of food supplement participates in phase II of clinical trials for congenital disorders of glycosylation (CDG) patients. CDG is a group of more than 130 inborn errors of metabolism affecting N-linked, O-linked protein and lipid-linked glycosylation. In addition, monosaccharide is used in clinical trials phase I in patients with focal segmental glomerulosclerosis (FSGS), where the galactose lowers the level of a circulating factors that increase glomerular permeability to albumin in patients with resistant FSGS.