Effect of sulfa drugs on kidney function and renal scintigraphy

The sulfonamide group is widely used for bacterial diseases including kidney and urinary tract infections. The present study investigates the effect of a sulfa drug on kidney function and renography studies by using a radionuclide.

Renography studies were performed on New Zealand white rabbits. Each rabbit was injected with 48.1 MBq technetium-99m mercaptoacetyltriglycine ((99m) Tc-MAG-3). Dynamic images were acquired using a gamma camera. Radioactivity time curves were generated from the regions of interest, time to peak activity (Tmax ) and time from peak to 50% activity (T1/2 ). Each rabbit served as its own control. The sulfa drug was given to these rabbits for 7 days (i.v injection 130 mg/kg daily in two divided doses; i.e. the single dose is 65 mg/kg), then dynamic images were acquired.

Treatment with sulfa shifted the experimental curves to the right of the control curves. This result showed that there was a delayed renal uptake of (99m) Tc-MAG-3 and its clearance. Calculated averages of Tmax were 2.2 ± 0.3 and 5.9 ± 0.5 min; while for T1/2 were 3.1 ± 0.3 and 8.4 ± 0.6 min for control and sulfa-treated rabbits, respectively (n = 20; P < 0.05).

Our results indicate that sulfa drug induced pharmacokinetic changes because of delaying both the Tmax and T1/2 . Sulfa drug has an effect on the reabsorption from the renal tubules and the excretion process of (99m) Tc-MAG-3 which is excreted almost exclusively by the renal tubules. Therefore, sulfa drug causes a deterioration in kidney function and an alteration on radionuclide renography.