Antireactive properties of "chondroprotective" drugs

The medicinal therapy of osteoarthritis is based on the use of analgesics, NSAIDs and corticosteroids to relieve pain and inflammation. In addition, "chondroprotective" agents (CPA) are used to stop the evolution of the disease. In this review the biochemical and pharmacological activities of some of the most widely used CPAs are described. All of these show more or less marked antiinflammatory activities, which for some of them are the result of an inhibition of cyclo-oxygenase and of prostaglandin biosynthesis, in which case they should be more properly classified as mild NSAIDs. Only two of the CPAs reviewed, diacerein and D-glucosamine sulfate, elicit antiinflammatory and antireactive effects without significant inhibition of the prostaglandin biosynthesis. These agents have also remarkable chondroprotective effects, and only these two agents should be classified as true CPAs. In particular glucosamine sulfate, which naturally occurs in the human body and is almost devoid of toxicity, is suitable for long-term therapeutic use. This, with its chondrometabolic, antireactive and antiarthritic properties, represents the pharmacological rationale for the use of glucosamine sulfate as a disease-modifying agent in osteoarthritis.