Preliminary experience with diacetylrhein in the treatment of osteoarthritis.

A single-blind, placebo controlled study was carried out over a 12-week period in 12 patients with osteoarthritis of the hip or knee to assess the effectiveness of 50 mg diacetylrhein per day. The 4 weeks of active treatment were preceded and followed by periods on placebo. Response to treatment as assessed by pain score, walking time and the number of 'rescue' analgesic tablets (paracetamol) consumed showed that 6 patients improved, 4 were unchanged and 2 deteriorated. Improvement was not apparent for several weeks after starting active treatment and remission lasted for 2 weeks to 3 or more months after the drug was withdrawn. The action of diacetylrhein is not yet established, but it does not appear to be related to analgesia or inhibition of prostaglandin synthetase activity. It is considered that further studies of this interesting drug are warranted to determine the most effective dose and duration of treatment.