Urinary Concretions Caused by Sulfapyridine

Abstract

Sulfapyridine is being widely used in clinical experiments because of its alleged lack of toxicity and the promising results reported by Whitby, 1 and by Evans and Gaisford. 2 However, our investigations, 3 , 4 as well as those of others, 5 , 6 have failed to confirm Whitby's claims that the drug is capable of protecting mice against 10,000 fatal doses of pneumococci; and we have pointed out that the order of efficacy of this drug and of sulfanilamide is approximately the same in rats. Marshall, Bratton and Litchfield 7 have recently issued a warning in regard to the erratic absorption and the potential toxicity of the drug, stating that sulfapyridine should not be used where sulfanilamide is indicated. Long and Finestone 6 have also drawn attention to the fact that the absorption and excretion of sulfapyridine are erratic.

In the course of an investigation concerning the delayed deaths of rats treated with sulfapyridine, we noted that although the infections were in some instances apparently cured, the kidneys were enlarged and soft, the pelves and ureters dilated, and the bladders empty and contracted. Careful examination of the urinary tract revealed crystalline, spiculated, white or yellow concretions and sand, often impacted, with more or less complete urinary obstruction. A chemical analysis of these concretions indicated 6.4% sulfapyridine and 64.1% acetylsulfapyridine. These findings were absent in untreated rats, and in rats treated with sulfanilamide; all of which had been on the same diet. The dosage employed was the same for both drugs: one-half to one gram per kilo per day for 8 to 14 days.

Higgins 8 has produced urinary calculi in rats with vitamin A deficient diet.