Colchicine--expanding horizons.

To say that the once very limited indications for colchicine have undergone a subtle but definite and dramatic change in recent years would not be an overstatement. This old drug, which has been known for centuries, was used for relieving and preventing acute attacks of gouty arthritis for over 200 years, but until recently, no other clinical uses had been established. The 1985 edition of Good-man & Gilman's standard textbook of phar-macology for example, states that'.. . colchicine is largely effective only against gouty arthritis', and devotes no more than five lines (of the two pages discussing the drug) to its possible effect in other conditions.' However, intriguing data have been obtained since, which suggests that colchicine may be highly efficacious in several common and important though diverse clinical syndromes for which no other equally effective therapy is known. In gouty arthritis, its classical indication, the role of colchicine has been recently questioned since serious toxicity may be associated with its use, and since other agents such as indomethacin are as effective, and may be better tolerated.2'3 However, long experience has shown that the drug is remarkably well tolerated,4 and that cases of severe systemic toxicity are rare and often reflect inappropriate use of the drug5 (intravenous administration which exceeded 4 mg for a single course of therapy). The most common adverse effects of colchicine are relatively minor gastrointestinal symptoms, which are useful early signs of impending toxicity. Colchicine produces a striking response in acute gout where 0.5 mg is usually given orally, every 1-2 hours to a maximum of8-10 mg, until relief or gastrointestinal symptoms occur. Pain and swelling usually abate within 12 hours of starting therapy and a major objective improvement of joint inflammation is evident within 48 hours and can be used as a diagnostic aid. The drug reduces the inflammatory reaction to urate crystals without causing analgesia or affecting uric acid metabolism.6 Colchicine is also highly efficacious for the long-term prophylaxis of recurrent gout and the prevention of acute attacks during the first few months of treatment with allopurinol or urico-surics.4 One to two mg/day of colchicine may also be effective for prophylaxis of pseudo-gout7 and treatment of sarcoid arthropathy,8 psoriatic arthritis ,9 and Paget's disease of bone,'" though at present the amount of information is inadequate for definite conclusions. In recent years, however, additional indications for the use of colchicine have been identified, for which …