Plasma osmolality, iodine concentration and urographic images following high and low osmolar contrast media

Three contrast media (sodium iothalamate, iopamidol and sodium/methylglucamine ioxaglate) in a dose of 240 mg iodine per kilogram of body weight were compared in clinical urography. The ionic monomer sodium iothalamate was the only medium to significantly elevate the plasma osmolality though it returned to normal values within 4 min. All three media exhibited first order linear kinetics. When corrected for the effects of diuresis, sodium iothalamate was shown to give the highest urinary iodine concentrations. On visual scoring sodium iothalamate produced better nephrograms and overall urograms than either of the low osmolar agents.