Analgesic agent comprising cyclic phosphatidic acid derivative

A method of alleviating pain comprising administering an effective amount to a patient in need thereof, a compound represented by the formula (1):

• wherein R presents C1-C30 linear or branched alkyl, C2-C30 linear or branched alkenyl, or C2-C30 linear or branched alkynl, provided that such groups are optionally substituted by a cycloalkane ring or an aromatic ring;
• X and Y each independently represents —O— or —C2—, provided that X and Y do not simultaneously represent —CH2—;
• and M represents a hydrogen atom or a counter cation, or a pharmacologically acceptable salt thereof, to alleviate pain.