Double-blind study of ketoprofen and phenylbutazone in ankylosing spondylitis.

A series of 26 patients with ankylosing spondylitis have been included in a double-blind cross-over comparison of ketoprofen 200 mg daily and phenylbutazone 300 mg daily, each drug being given for 4 weeks, with paracetamol as a 'rescue drug'. Six patients withdrew from the study: three on phenylbutazone and one on ketoprofen--two defaulted treatment. Twenty patients (17 males and 3 females) were eligible for assessment. Their ages ranged between 20 and 59 years (mean 40.2 years). Patient characteristics were comparable in both groups. The results of this series indicate no suggestion of statistically significant differences in any of the nine movements measured. The only significant differences, both in favour of phenylbutazone, were in the paracetamol consumption in the second treatment period in the group receiving ketoprofen first (0.01 greater than P greater than 0.005) and in the patients' preference for phenylbutazone (0.005 greater than P greater than 0.001). Adverse reactions were comparable in both groups.