Condensed pyridine compounds represented by formula (I): wherein: R1 and R3 are, independently, hydrogen, lower alkyl, or lower alkoxy; R2 represent an amino substituent; ring A is a benzene ring, pyridine ring, thiophene ring, or furan ring; and B represents a substituent containing a ring structure. Also, pharmaceutically acceptable salt and hydrates thereof. These compounds are clinically useful medicaments having serotonin antagonism, and in particular, for treating, ameliorating, or preventing spastic paralysis. They are also useful as central muscle relaxants for ameliorating myotonia.