THE RENAL EXCRETION OF SULFANILAMIDE IN DOGS

¹ Bureau of Biological Research, Rutgers University
² Raritan Hospital for Animals, Stelton, N. J.

The maximum variation in urea clearance and sulfanilamide clearance on one normal dog on a standard mixed diet and under hospital conditions was established.

The average sulfanilamide clearance was found to be approximately 36 per cent of the average urea clearance and 20 per cent of the average creatinine clearance in this dog with normal renal function. This sulfanilamide/urea clearance ratio varied between 0.24 and 0.48 but was independent of the rate of urine flow. These findings support the conclusion reached by Marshall, Emerson and Cutting that sulfanilamide is excreted in a similar way to urea but is reabsorbed to a greater extent by the tubule.

The sulfanilamide clearance is lowered in general, as the urea clearance is reduced due to kidney damage. The sulfanilamide/urea clearance ratio does not, however, always remain the same as in the normal kidney. In many of the cases presented the ratio increases when there is any lowering in the urea clearance. it is suggested that this ratio, and perhaps other ratios, may be used to indicate kidney damage as well as to give more information concerning kidney function.

It is apparent that dosage should be based upon maintenance of blood sulfanilamide level rather than body weight.