Three month treatment of reactive arthritis with azithromycin: a EULAR double blind, placebo controlled study

OBJECTIVE

To determine the efficacy of weekly treatment with oral azithromycin for 13 weeks on the severity and resolution of reactive arthritis (ReA).

METHODS

186 patients from 12 countries were enrolled in a randomised, double blind, placebo controlled trial. Inclusion criteria were inflammatory arthritis of < or =6 swollen joints, and disease duration of < or =2 months. All patients received a single azithromycin dose (1 g) as conventional treatment for possible Chlamydia infection, and were then randomly allocated to receive weekly azithromycin or placebo. Clinical assessments were made at 4 week intervals for 24 weeks.

RESULTS

152 patients were analysable (34 failed entry criteria), with a mean (SD) age of 33.8 (9.4) and duration of symptoms 30.7 (17.5) days. Mean C reactive protein (CRP) was 48 mg/l, and approximately 50% of those typed were HLA-B27+, suggesting that the inclusion criteria successfully recruited patients with acute ReA. Treatment and placebo groups were well matched for baseline characteristics. There were no statistical differences for changes in any end point (swollen and tender joint count, joint pain, back pain, heel pain, physician and patient global assessments, and CRP) between the active treatment and placebo groups, analysed on an intention to treat basis or according to protocol completion. The time to resolution of arthritis and other symptoms or signs by life table analyses was also not significantly different. Adverse events were generally mild, but were more commonly reported in the azithromycin group.

CONCLUSIONS

This large trial has demonstrated that prolonged treatment with azithromycin is ineffective in ReA.

Function of human alveolar macrophages after a 3-day course of azithromycin in healthy volunteers

Azithromycin (AZM) is a new macrolide antibiotic with a high intracellular/extracellular concentration ratio. Immunomodulatory and antiinflammatory properties have been reported with other macrolides, especially erythromycin. The aim of the present study was to evaluate the effect of AZM on the production of proinflammatory mediators by alveolar macrophages (AM) up to 4 weeks after a 3-day course of AZM (500 mg, once a day). Nineteen non-smoking healthy male subjects were investigated with bronchoscopy and bronchoalveolar lavage. Group 1 received no treatment. Groups 2, 3, and 4 were bronchoscoped 1, 7 and 30 days, respectively, after AZM administration. AZM concentrations were simultaneously measured in plasma and in AM extracts. In serum, AZM levels were higher in group 2 (32.8 +/- 14.2 micrograms/l), at the lower limit of detection in group 3 (2.8 +/- 1.7 micrograms/l), and no longer detectable in group 4. In AM extracts, the highest concentrations were measured in group 2 (51.6 +/- 28.3 ng/microliter) and in group 3 (31.8 +/- 17.2 ng/microliter), and were detected up to 30 days after treatment in group 4 (2.9 +/- 2.3 ng/microliter). There was no significant differences between groups for blood or BAL proinflammatory cytokines levels (TNF-alpha, IL-1 beta, IL-6), and for superoxide generation by AM. We conclude that a 3-day course of AZM 500 mg/day in healthy subjects does not alter the proinflammatory cytokine profile in blood and in AM despite the prolonged tissue impregnation by this drug.