Compounds of formula (1) (in which R<1> R<2>, R<3> and R<4> are the s"ame as or different from each other and each represents an oxo group, a hydroxy group, a mercapto group, a hydrogen atom, a halogen atom, an alkoxy group or an aryloxy group and the dotted line indicates that there may be a single or dour e bond between one of the respective pairs of carbon atoms) and esters thereof can be administered by transdermal administration. They are particularly effective when applied as a patch, preferably with an adhesive comprising a copolymer of from 40 to 60% by weight of methoxyethyl acrylate, from 30 to 40% by weight of lauryl acrylate or lauryl methacrylate and from 10 to 25% by weight of a polar monomer.
