The suppressive and prophylactic action of puromycin was tested on patients of a mental hospital who were exposed to a high rate of infection with intestinal protozoa. In an exposed group of cases receiving 100 mgm. of the drug daily for 10 days, about half the amebic infections were cured and most of the rest were suppressed. Weekly administration of as much as 500 mgm. for 5 weeks effected few cures and failed to prevent new infections.
A group of patients on a heavily infected ward were then cleared of protozoa with one gram of puromycin daily for 4 days, and about half of these were continued on a prophylactic regimen of 250 mgm. thrice weekly for 6 weeks. The unprotected group began to acquire infections during the 4th week after cessation of treatment, while the rest remained uninfected throughout the 6 weeks of prophylaxis, although constantly exposed. Two weeks after prophylaxis was discontinued, this group also began to acquire infections.
All the patients receiving one gram daily had diarrhea on the 4th day and a few vomited, but these reactions disappeared on reducing or withdrawing the drug. The lower dosages did not produce side reactions.