[Papaverin--effective in therapy of pruritus of atopic dermatitis?].

Patients suffering from atopic dermatitis show increased phosphodiesterase activity in leucocytes. As a result, the level of intracellular c-AMP is reduced, which can produce a number of metabolic dysfunctions: We found strong evidence that an enhanced release of several inflammation mediators can favor itching, which in turn promotes the development of eczema, since it induces reflectory scratching. In order to solve the question whether papaverine as a phosphodiesterase inhibitor might offer a new approach in the systemic therapy of itching, we performed a placebo-controlled study on 51 patients with atopic dermatitis, who were orally treated with papaverin-HCl over 8 weeks. However, we did not observe any improvement of itching or eczema during treatment. Some other recently developed phosphodiesterase inhibitors are discussed.