Thyroid, renal, and hepatic function tests following cholecystography with high-dose contrast agents

Serum biochemical tests were observed for about three weeks following oral cholecystography with fractionated high doses (6 g) of iopanoic acid (Telepaque) or sodium ipodate (Biloptin) in 24 and 29 patients, respectively. Both agents produced similar effects. No significant changes were seen in renal or hepatic function except for a mild increase in bilirubin on day 22. Serum urate decreased 10% on day 4, but the change was not significant. On days 4 and 11, there were significant increases in thyroid-stimulating hormone, thyroxine and free thyroxine index, and a moderate fall in triiodothyronine. Reverse triiodothyronine increased sharply on day 4. The pattern of changes observed suggests that these contrasts interfere with the extrathyroidal deiodination of iodothyronines. The temporary rise in thyroxine and free thyroxine index exceeded reference ranges in about half of all subjects, but they remained clinically euthyroid. Thyroid function tests should be interpreted with caution within three weeks of cholecystography.