Parenteral high dose methotrexate and sulfasalazine are the only two agents with well demonstrated published efficacy in psoriatic arthritis. The magnitude of the effect seen with azathioprine, etretinate, oral low dose methotrexate and perhaps colchicine suggests that they may be effective but that further multicentre clinical trials are required to establish their efficacy. Furthermore, the magnitude of the improvement observed in the placebo group strongly suggests that uncontrolled trials should not be used to guide management decisions in this condition.
Therapeutic value of colchicine in the treatment of patients with psoriatic arthritis.
To test the hypothesis that colchicine is an effective treatment of psoriatic arthritis.
                Twenty five patients with psoriatic arthritis were entered into a two centre, double blind, crossover study of 23 weeks' duration comparing the therapeutic effect of colchicine (0.6-1.8 mg/day) with placebo.
                No significant difference was noted between colchicine or placebo treatment for the primary outcome measure (Lansbury joint count) or any of the seven secondary outcome measures. No change in the psoriasis was noted during active or placebo treatment. Adverse clinical effects were reported more often during treatment with colchicine (14 patients) than with the placebo (four patients), resulting in the early withdrawal of three patients receiving colchicine from the trial. Increased creatine kinase values, without weakness, occurred during treatment with colchicine (five patients) and placebo (four patients).
                In conclusion, our study did not provide evidence that colchicine is of therapeutic value in the treatment of psoriatic arthritis.