Effect of Selected Antibiotics on Prothrombin Time of Rats and the Relationship to Coumarin Anticoagulants 1

Abstract

Summary

Antibiotics with known intracellular sites of action, viz. Nogalamycin, actinomycin D, puromycin, and cycloheximide, were given to rats in vivo to determine which of them produce effects comparable to the coumarin anticoagulants. All of these agents prolonged the prothrombin time, however, in the case of Nogalamycin and actinomycin such effects could not be produced unless lethal amounts were used. A comparison of the onset of effect of these agents with warfarin was made. Nogalamycin and actinomycin showed a marked delay in onset while the effect of puromycin and cycloheximide coincided closely with warfarin which suggests that warfarin does not act at the same site as Nogalamycin and actinomycin D. Since puromycin and cycloheximide simulated the action of warfarin during the early part of the time course, it seems likely that warfarin may act at or close to the site of action of these agents.