Trials with xanthine derivatives in systemic treatment of psoriasis.

The psoriatic epidermis is more active metabolically and its rate of proliferation is faster, showing incomplete differentiation as a result of the imbalance between the low level of cyclic AMP and the high level of cyclic GMP. The low cyclic AMP levels are due to hyperactivity of the phosphodiesterase which hydrolyzes cyclic AMP. Xanthine derivatives are found to be potent phosphodiesterase inhibitors. 15 psoriatic patients were treated with tablets of xanthine derivatives (dyphylline, aminophylline). The obtained results are discussed.