Kyowa Hakko Kogyo Co., Ltd.

Shizuo Shioazaki

Fumio Suzuki

Akio Ishii

Junichi Shimada

Shunji Ichikawa

Hiromi Nonaka

Joji Nakamura

Nobuaki Koike

Agents for the treatment of Parkinson's disease contain, as an active ingredient, a xanthine derivative or a pharmaceutically acceptable salt thereof. The xanthine derivative is represented by the formula: ##STR1## in which R.sup.1, R.sup.2 are R.sup.3 are independently hydrogen, lower alkyl, lower alkenyl, or lower alkynyl; and R.sup.4 represents cycloalkyl, --(CH.sub.2).sub.n --R.sup.5 (in which R.sup.5 represents substituted or unsubstituted aryl or a substituted or unsubstituted heterocyclic group; and n is an integer of 0 to 4), or ##STR2## in which Y.sup.1 and Y.sup.2 represent independently hydrogen, halogen, or lower alkyl; and Z represents substituted or unsubstituted aryl, ##STR3## in which R.sup.6 represents hydrogen, hydroxy, lower alkyl, lower alkoxy, halogen, nitro, or amino; and m represents an integer of 1 to 4, or a substituted or unsubstituted heterocyclic group; and X.sup.1 and X.sup.2 represent independently O or S.

Therapeutic agent for Parkinson's disease

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Fuji, Japan

Shizuo Shioazaki