A pharmaceutical formulation and topical administration thereof for the treatment of psoriasis or any one or more symptoms associated therewith. The formulation contains a therapeutically effective amount pemetrexed alone as the active agent or can contain therapeutically effective amounts of pemetrexed in combination with siRNA-inhibiting TNFα. The formulation may further include a cationic surfactant, such as cetylpyridinum chloride, and urea for enhanced permeation through the stratum corneum of the patient or subject.
