Topical tacrolimus for the treatment of inflammatory skin diseases.

Chronic inflammatory skin disorders, such as atopic eczema, can cause considerable impairment of life quality. Their treatment is mainly driven by systemic or topical glucocorticosteroids which have the risk of many side effects. Recently, immunosuppressive macrolides which act via the inhibition of cytokine expression in T-lymphocytes have been shown to exert good therapeutic potency in inflammatory skin disorders. Cyclosporin, widely used in transplantation medicine, is also effective in psoriasis and atopic eczema but is not suitable for topical treatment. Tacrolimus (FK506) has been found to be 10-100 times more potent than cyclosporin and to penetrate skin much better due to a lower molecular weight. Initial clinical investigations have shown efficacy of topical tacrolimus in patients with atopic eczema. Large multi-centre studies have proven that long-term therapy with 0.03% and 0.1% tacrolimus ointment reveals effectiveness and safety both in adults and in children with severe atopic eczema. A burning sensation at the site of application is the most frequently observed local side effect. Relevant systemic adverse events were not detected. In Japan and the US, the drug is already licensed for the treatment of atopic eczema. The European admission for the pharmaceutical market is expected in the year 2002. Tacrolimus represents a milestone in topical therapy of inflammatory skin disorders which has so far been dominated by corticosteroid formulations and gives hope for the development of further topical immunosuppressive agents of its class in the future.