A medicament for therapeutic and prophylactic treatment of diseases caused by hyperplasia of the smooth muscle cells are

摘要

A medicament for the therapeutic and prophylactic treatment of a disease caused by smooth muscle cell hyperplasia which comprises as an active ingredient an aminopyridazine derivative or a salt thereof represented by the following Formula (I), e.g. (R) - 1 - (cyclohexylethylamino) - 4 - phenylphthalazine.