Source: NeuroImage  |  Posted 8 years ago

Improvement of disease activity is observed with tetracycline treatment in patients with rheumatoid arthritis, particularly in combination with minocycline, and in the treatment of patients with early disease, according to a recent Canadian study.

A bacterial cause for rheumatoid arthritis has been hypothesised for years, as it has been determined that the pathologic mechanism of rheumatic disease resembles that of an immunologic reaction between antigen and antibody.

The use of antibiotics, such as tetracyclines, in the treatment of rheumatoid arthritis has been proposed and is still under investigation with promising initial results.

Millicent Stone, MB MRCP (UK), and colleagues at the University of Toronto and Toronto Western Hospital, Ontario, Canada, conducted a meta-analysis to evaluate the effectiveness of tetracycline in reducing disease activity in patients with rheumatoid arthritis.

The analysis included 10 randomised controlled trials (3 high quality, unbiased trials) enrolling a total of 535 patients with rheumatoid arthritis that received tetracycline, conventional disease modifying antirheumatic therapy or placebo.

The analysis found that a significant reduction in disease activity is observed when tetracyclines are taken for 3 months or longer. Specifically, the mean tender joint count (TJC) decreased by 0.39 joints with tetracycline treatment as did the eosinophil sedimentation rate (ESR, -7.96). However, no improvements were seen in radiological progression of disease as determined by the degree of erosion.

Results also indicated that tetracycline treatment was most effective in patients who were seropositive and who had rheumatoid arthritis for less than 1 year. Moreover, minocycline alone showed the greatest effect on reduction of disease activity (TJC mean difference of -0.69 and ESR mean difference of -10.14), though doxycycline trials were excluded from this analysis.

Overall, there was no absolute increased risk of adverse events associated with tetracycline use. However, insufficient data was available regarding individual side effects from these studies.

The authors conclude that "tetracyclines, in particular minocycline, were associated with a clinically significant improvement in disease activity in rheumatoid arthritis with no absolute increased risk of side effects." They also advocate that "further research is warranted to compare these agents to newer disease modifying drugs for comparable safety, efficacy, and cost-effectiveness."