Sulfapyridine and Vomiting

It is generally conceded that nausea with vomiting is the most common toxic manifestation of sulfapyridine therapy and may appear in approxdmately 60 to 70 per cent of cases treated with the drug. Occasionally the vomiting is so severe as to make necessary the cessation of therapy. Explanations proposed for the mechanism of this vomiting fall into two groups, namely, a local effect upon the gastro-intestinal tract and a central effect upon the vomiting center. The latter view is supported by the work of Marshall and Long,' who have observed that vomiting is produced both in dogs and man when sodium sulfapyridine is given intravenously. That this explanation may not be entirely correct, however, has been suggested by Haviland and Blake,' who found that the sulfapyridine concentration in vomitus of patients receiving sulfapyridine by a parenteral route-only may be considerably higher than that in the blood. In addition, we have observed that sulfapyridine is excreted into the stomach of the dog with surprising rapidity following the intravenous injection of sodium sulfapyridine. In Table 1 are summarized the results of ten experiments in which a 5 per cent solution of sodium sulfapyridine was injected intravenously into dogs until vomiting was produced. As soon as possible after the act of vomiting, a specimen of blood was taken from the dog. In both this and the vomitus the concentration of non-acetylated sulfapyridine was determined by the method of Marshall and Litchfield.4 The time at which emesis occurred after beginning the injection of sulfapyridine is also recorded. The results show that within 4 to 52 minutes after beginning the injection of the drug, sulfapyridine was frequently present in the vomitus in a concentration nearly as high as