| abstract |
(wherein R 1 , R 2 and R 3 are the same or different, and represent a hydrogen atom, lower alkyl, lower alkenyl or lower alkynyl; R 4 represents cycloalkyl, —(CH 2 ) n —R 5 or a group represented by the above formula (II); and X 1 and X 2 are the same or different, and represent an oxygen atom or a sulfur atom) n nThe present invention provides, for example, agents for treating migraine comprising, as an active ingredient, a xanthine derivative represented by the above formula (I) or a pharmaceutically acceptable salt thereof. |