Sodium versus Meglumine Diatrizoate in Excretory Urography

Abstract

In anesthetized dogs the i.v. injection of mannitol, sodium diatrizoate, meglumine diatrizoate or meglumine hydrochloride produced diuresis approaching a steady-state. During this period the apparent volumes of distribution of meglumine and diatrizoate were similar and greater than that of inulin; the plasma concentration, renal clearance, and rate of urinary excretion were the same for meglumine and diatrizoate; their renal clearance was identical with that of inulin. Excretion of urine and urinary electrolytes was greater after meglumine diatrizoate than after sodium diatrizoate or meglumine hydrochloride. Urinary concentration of diatrizoate was greater after sodium than after meglumine diatrizoate; the relative radiopacities should be as 11/9. This difference is believed to result from the influence of the two impermeant ions on the excretion of other ions on a statistical basis. Single-dose experiments revealed no such difference between sodium and meglumine diatrizoates due to errors arising from collection of urine from the bladder.