The present invention provides a DP receptor antagonist. General formula (I): (In the formula, all symbols are as shown in the specification.) The compounds represented and their pharmaceutically acceptable salts have DP receptor antagonistic activity and high safety, so they are used for DP receptor mediation Effective ingredients of medicines for diseases are useful. In addition, the compound represented by the general formula (I) and the pharmaceutically acceptable salts thereof also have good migration to the central nervous system. Therefore, as DP receptor-mediated diseases, they are particularly affected by the DP present in the central nervous system. It is useful as a preventive and/or therapeutic agent for body-related diseases, that is, sleep-wake disorder.本發明提供一種DP受體拮抗劑。通式(I)：(式中，全部之記號如說明書中所示)所表示之化合物、及其藥學上所容許之鹽由於具有DP受體拮抗活性，且安全性亦高，故而作為用於DP受體介導性疾病之醫藥品之有效成分有用。又，通式(I)所表示之化合物、及其藥學上所容許之鹽由於亦具有良好之向中樞之移行性，故而作為DP受體介導性疾病中尤其是與存在於中樞之DP受體相關之疾病、即睡眠覺醒障礙之預防及/或治療劑有用。
