Phosphodiesterase (PDE-4) activity was found to be greater in psoriatic skin than in healthy skin. Inhibition of PDE-4 inhibits the hydrolysis of cyclic AMP in inflammatory cells, which increases intracellular cAMP and results in down-regulation of immune modulators, including tumor necrosis factor (TNF)- α, interferon-γ, interleukin (IL)-17, and IL-23. Roflumilast is a potent and selective inhibitor of PDE-4 which is already approved in its oral form for chronic obstructive pulmonary disease. Regarding Roflumilast's topical form, it is currently also approved in the treatment of psoriasis. Lebwohl et al., 2020 found that roflumilast cream was efficacious in reducing the severity of psoriasis in a 12-week, randomized, double-blind, placebo vehicle-controlled trial.
Roflumilast is a phosphodiesterase-4 (PDE-4) inhibitor, which is approved in its oral form for chronic obstructive pulmonary disease, and in its topical form in the treatment of plaque psoriasis. Methotrexate is one of the conventional systemic treatments of psoriasis, so the aim of this study is to compare the efficacy and safety of roflumilast and methotrexate in the treatment of psoriasis