Absorption of contrast medium during ERCP.

In order to assess systemic absorption, serum diatrizoate levels were measured in 25 patients requiring endoscopic retrograde cholangiopancreatography (ERCP). Urinary diatrizoate was measured in the urine of seven of these. In five additional patients, diatrizoate was instilled into the duodenum during endoscopy. Blood was drawn before and after completion of the procedure in all patients and at intervals from 2 to 24 hr in nine. Eighteen-hour urine collections were obtained from seven patients. Increases in serum diatrizoate concentration were 7.10 micrograms/ml +/- 3.01 (mean +/- SE) in the duodenal-instillation patients, 230.68 +/- 53.24 micrograms/ml in 9 patients in whom only the pancreatic duct was visualized, 7.83 +/- 1.05 micrograms/ml in three patients in whom only the bile duct was visualized, and 77.67 +/- 28.22 micrograms/ml in 13 patients in whom both ducts were visualized. The mean total urinary excretion of diatrizoate was 3.05 +/- 0.98 g of diatrizoate. Endoscopists performing ERCP should be aware of the likelihood of systemic absorption and the possibility of reactions to iodinated contrast materials in sensitive patients.