synthesis and biological testing of nonionic iodinated x-ray contrast media

Iohexol and iopamidol: second-generation nonionic radiographic contrast media

Iohexol and iopamidol are new second-generation nonionic contrast media. We review their physical/chemical properties and describe the improvements made over the first-generation nonionic prototype, metrizamide, and conventional ionic contrast media. The significance of low osmolar solutions is discussed and the relationship between osmolality and adverse reactions is emphasized. The convenience of a ready-to-use stable solution that offers an advantage over the lyophilized metrizamide in practical application is suggested. Clinical studies using randomized, double-blind comparison techniques are cited. An attempt is made to define the exact role for iohexol and iopamidol.

Iopamidol in lumbar myelography

Iopamidol is a new, nonionic, water-soluble contrast material currently undergoing clinical trials for intravascular and intrathecal use in Europe and the United States. In this study, 12 patients underwent lumbar myelography with this agent. For each subject, up to 12 mL of iopamidol (at 200 mg I/mL) was employed. The myelograms obtained were highly satisfactory. No serious adverse reactions were observed. The most common side effect--headache--occurred in seven patients. However, six of the seven headaches were mild and transient, and did not require treatment. Nausea occurred in two patients, back pain in two patients, hypotension and hypertension each in one patient. All of these reactions were mild and self-limited. Iopamidol appears to be a safe and conveniently used agent for lumbar myelography.

Ionic and non-ionic contrast media interaction with anticoagulant drugs

Normal and pathologic human plasmas were incubated with radiographic contrast media, heparin, Dextran-40 and saline. Renografin-60 produced a strong anticoagulant effect and the clotting times were significantly prolonged; the addition of heparin resulted in greatly elevated thrombin time. No such prolongation was noted with Dextran-40. P-297, ioxaglic and ioxithalamic acids also showed similar anticoagulant properties. When dogs were injected with contrast media and heparin, the overall anticoagulant effect lasted for more than 6 hours, while contrast media or heparin effect remained for a short period of time. Clinical significance of contrast media interactions with anticoagulant drugs is discussed.