Condensed pyridine compounds represented by formula (I): wherein: R1 and R3 are, independently, hydrogen, halogen, lower alkyl, or lower alkoxy; R2 represents 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.