Oral cholecystography

Iopanoic acid is as potent a uricosuric agent as probenecid and this effect might explain some renal complications aspirin reduces the uricosuric effect but can also impair X-ray visualization because of competition at plasma protein-binding sites. Fluctuations of serum urate after oral cholecystography can interfere with diagnostic tests and even precipitate an attack of gout (578). 

Insausti CL, Lechin F, van der Dijs B. Severe thrombocytopenia following oral cholecystography with iocetamic acid. Am J Hematol 1983 14(3) 285-8. 

In the following sections, selected examples of synthesis for ionic and nonionic, and monomeric and dimeric contrast agents are given to illustrate the general synthetic approach. The synthesis of an ionic monomer iocetamic acid (6a), atriiodoanilideofthe NNHtype, used for oral cholecystography (240), is shown in Equation 10.4. 

Intravascular contrast agents should have low viscosity and low osmolality as close as possible to those of body fluids, to improve tolerance and minimize adverse reactions. Contrast agents intended for oral cholecystography should possess hydrophilic and lipophilic properties, so that the compoundcan be orally absorbed, should be excreted from the liver and bile ducts in sufficient amount to provide radiopacity, and should have no adverse side effects. Because each of these properties is associated with certain molecular features and not all of them are structurally compatible, the best radiopaques represent a compromise of a maximum of these desirable qualities. 

Ipodate, introduced in 1961, can yield visualization of both gall bladder and bile ducts. Tyropanoate, iopanoic acid, and ipodate are widely used in oral cholecystography. They show about the same efficacy but differ in the intensity of opacification,the frequency of dim and absent shadows, and the frequency of side effects. Russell and Frederick (867) compared these three agents but failed to demonstrate the superiority of any one of them. locetamic acid was favorably compared with and preferred to the above three agents, but skin reactions were reported in a few cases (775,868, 869). 

The effects of cholecystographic media on iodine metabolism have been discussed in SED VIII. Two cases of frank thyrotoxicosis have recently been reported following oral cholecystography. In both of these cases, symptoms commenced a few days after taking sodium iopodate (11 ). 

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