Intermittent Control of Hyperuricaemia in the Treatment of Gout

Abstract

Nucleation of urate crystals requires a high degree of supersaturation although it may be enhanced by various agents such as calcium, decreasing pH and mechanical shock¹. Growth rate is also very strongly dependent on supersaturation and appears to be very slow at physiological degrees of supersaturation. In contrast, dissolution rates are very fast compared with growth, being limited by the rate at which the urate can diffuse away from the crystal surface². This has led to the suggestion that periodic short-term lowering of serum urate in patients with gout might be as effective as constant treatment, a few days of normouricaemia every year being sufficient to eliminate small deposits³. Such a concept is attractive both with regard to financial economy (allopurinol costing approximately £300 per patient per year at a dose of 300mg daily) and perhaps to compliance, the idea of short intermittent periods of treatment being more acceptable to some people than long term continuous administration.