Solute excretion during intravenous urography: a comparison of sodium and methylglucamine iothalamates.

The sodium and methylglucamine salts of iothalamic acid were compared as urographic agents. The two drugs were administered intravenously to dogs at a dose of 600 mgI/kg. The outputs and concentrations of the major urinary solutes and the injected solutes were measured to define the differences in renal excretion of sodium and methylglucamine iothalamates. The action of methylglucamine as a relatively inert osmotic diuretic was reconfirmed. When sodium iothalamte was adminstered the tubular reabsorption of sodium and chloride was greater than when methylglucamine iothalamate was used. It is suggested that this reabsorption explains the advantage of sodium-linked agents over methylglucamine-linked agents in urography.