Salicylazosulfapyridine (salazopyrin or azopyrin) in rheumatoid arthritis and experimental polyarthritis.

Thirty patients with rheumatoid arthritis were treated with Salazopyrin(R) for periods from two months to one year. Fourteen patients were symptomatically relieved in varying degrees. This group included seven patients not previously benefited by gold therapy and four who had had toxic reaction to gold. The sedimentation rates tended to remain elevated in spite of symptomatic improvement. Extension of disease to joints not formerly involved appeared in only one patient under treatment. Continuation of small dosage for long intervals seemed advantageous in the small number of patients treated in this study. Fourteen patients were not relieved symptomatically by Salazopyrin, but they did not become worse. This group included eight patients with severe, advanced disease, six of whom had not been benefited by chrysotherapy. In one patient there was a moderate reduction in erythrocyte count and in hemoglobin. One patient refused medication, claiming extreme nervousness. Salazopyrin is variably and comparatively poorly absorbed in man. In experimental polyarthritis of rats, administration of 0.5 per cent Salazopyrin in the diet produced a slight beneficial effect, while 1 per cent made the infection worse. Changes in body weight and in leukocyte content in the blood of rats and mice showed Salazopyrin to have minimal toxic effect in these rodents.