PLASMA-LEVELS AND URINARY-EXCRETION OF IODINE AFTER ORAL-ADMINISTRATION OF IOHEXOL IN DOGS AND CATS

RATIONALE AND OBJECTIVES. Plasma and urinary iodine concentrations were assessed after oral administration of iohexol in five dogs and five cats. MATERIALS AND METHODS. Ventrodorsal and right lateral radiographs were taken; a 3-mL blood sample was collected 30 minutes and 1, 2, 4, and 6 hours after dose in each animal; and the bladder was emptied at 2 and 6 hours in dogs and at 6 hours in cats after oral administration of 700 mg I/kg iohexol (300 mg I/mL), Iodine concentration was measured using a sequential inductively coupled plasma atomic emission spectrometer system. RESULTS. Peak concentrations of plasma iodine were detected in samples taken from both dogs (0.33 mg I/mL) and cats (0.28 mg I/mL) 30 minutes after iohexol administration, with a gradual decline at 1, 2, 4, and 6 hours, Total urinary excretion during the 6 hours after the administered dose of iohexol was higher (4.3%) in cats than in dogs (2.0%). In each species, there was a relationship between gastrointestinal motility observed radiographically and the subsequent excretion of iodine in the urine. CONCLUSIONS. Results indicate that approximately 2% of the oral dose is absorbed and excreted in the urine of dogs within 6 hours, and approximately 4% of the dose is absorbed and excreted in cats.