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.