SOME ASPECTS OF THE PHARMACOLOGY OF SULFAPYRIDINE

¹ Department of Pharmacology and Experimental Therapeutics, The Johns Hopkins University

1. Sulfapyridine is more toxic than sulfanilamide for mice, rabbits, and dogs on the basis of blood concentration of the drug. Likewise, acetylsulfapyridine is more toxic than acetylsulfanilamide.

2. Sulfapyridine, although apparently no more depressant to renal function in dogs than sulfanilamide, in its conjugated form as acetylsulfapyridine may cause a marked lowering of kidney function as measured by creatinine clearance.

3. The absorption of sulfapyridine from the gastrointestinal tract is slower, less complete, and more variable than is that of sulfanilamide under the same conditions. The physical state as well as the solubility of the preparation used influence absorption.

4. Sulfapyridine resembles sulfanilamide in its ready penetration to all tissues and body fluids in a concentration not far removed from that of the blood. However, unlike sulfanilamide it is usually present in higher concentration in the liver than in other tissues; and, in addition, there is more variability in its distribution from animal to animal.

5. The mode of excretion of sulfapyridine by the kidney appears to resemble very closely that of sulfanilamide.