An Overview of the Clinical Pharmacokinetics of X-Ray Contrast Media

Abstract

Pharmacokinetic studies of contrast media are usually performed as preclinical trials in anaesthetised animals; however, results in humans have also been reported for this type of compounds. This paper reviews the existing data about x-ray contrast media in humans. In some cases, animal data are used in areas where no human data are available. The administration of contrast media is generally made via the intravenous, intra-arterial or intrathecal route. Diagnostic procedures are based on differential distribution to organs and between normal and abnormal tissue. Data are available for iodixanol, iohexol, iopamidol, iopromide, iothalamate and ioxaglate, but the kinetic distribution of all contrast media is similar. With the exception of biliary contrast agents, all compounds display limited plasma protein binding and do not undergo biotransformation. From the pharmacokinetic viewpoint, the main area of interest for these compounds is elimination. The majority of the data were obtained with iopamidol (of which 66 to 72% of the dose is excreted in the urine), iohexol, ioxaglate and iopromide. Some studies were performed in patients with renal impairment: in this case, metabolic clearance was abnormally elevated, suggesting the existence of significant compensatory factors such as hepatic metabolism, enterohepatic circulation and biliary elimination. New compounds, such as iodinated polymers for x-ray perfusion imaging and iopromide- or metrizamide-containing liposomes allowing liver enhancement are discussed.

How are pharmaceutical and personal care products (PPCPs) removed from urban wastewaters?

“…However, PPCPs are present at enzyme-subsaturating levels, which necessitate an oligotrophic metabolism (Daughton and Ternes 1999). Moreover, the chemical structure of some PPCPs is very complex and strong, as for example in the case of the X-ray contrast media iopromide, which has been designed for remaining unaltered during its application and is thus mainly excreted unchanged (Bourin et al 1997).…”

Delayed allergy-like reactions to X-ray contrast media: mechanistic considerations

“…The nonionic contrast molecules show no measurable binding to plasma proteins. They are rapidly distributed in the body and almost completely recovered unmetabolized in urine within 24 h [4].…”

Liposomes Coloaded with Iopamidol/Lipiodol as a RES-Targeted Contrast Agent for Computed Tomography Imaging

“…Most iopamidol is excreted in the urine (24). The disappearance of the renal enhancement peak observed after liposomal encapsulation showed that the usual mechanism used to clear the iodinated agent was altered by encapsulation.…”