Remedies for parkinsonism having efficacious pharmacological effects even if administered alone; and levodopa potentiators efficacious as a drug to be used in combination with levodopa in treating parkinsonism, each containing as the active ingredient compounds represented by general formula (1) or pharmacologically acceptable salts thereof, wherein R<1> represents lower alkyl optionally substituted by cycloalkyl; and R<2> represents lower alkyl.
REMEDIES FOR PARKINSONISM