Altered theophylline metabolism in patients with psoriasis

We observed two patients on theophylline therapy with concomitant severe psoriasis and a two- to threefold greater theophylline clearance than that reported in healthy, nonsmoking adults. There were no factors known to induce theophylline clearance. In both cases, the induction of theophylline metabolism was relatively selective for the 1-methyluric acid pathway. The altered metabolism in these patients appeared to correlate with the clinical severity of the disease. The data suggest the possibility that an observed lack of efficacy for theophylline in psoriasis may be related to pharmacokinetic effects. The concept that altered drug metabolism may occur in the presence of skin disease has important implications for pharmacotherapeutics in dermatology.