Inflammatory status and kynurenine metabolism in rheumatoid arthritis treated with melatonin

What is already known about this subjectThere is good evidence that oxidative stress, associated with the generation of free radicals, is a major contributor to joint damage in rheumatoid arthritis.It is also well established that melatonin is one of the most powerful, endogenous free radical scavengers, and it is very safe for human use.We have therefore examined whether melatonin might be a useful adjunctive compound with which to treat arthritis.What this study addsOnce-nightly administration of melatonin increases concentrations of some inflammatory markers, but patients experience no significant improvement in symptoms and no changes of proinflammatory cytokine concentrations.Melatonin is an effective antioxidant, but because it is either not sufficiently effective, or it has some proinflammatory activity, it is not likely to prove beneficial in patients