A therapeutic formulation comprises a topically acceptable semisolid vehicle and carbamazepine, the vehicle consisting of components that are compatible with the carbamazepine, and the carbamazepine being in a concentration sufficient to permit a therapeutically effective amount of the carbamazepine to be absorbed from the formulation into the skin of a patient. The vehicle may be a cream, ointment, or gel. A method of treating a skin condition of a patient such as psoriasis comprises applying carbamazepine topically to the patient's skin until the condition improves. A method of administering carbamazepine to a patient comprises applying a formulation comprising carbamazepine topically to the patient's skin.