AGENT FOR TREATMENT OF PULMONARY HYPERTENSION

PURPOSE:To obtain the subject treating agent having low toxicity and excellent therapeutic effect by using a specific compound (salt) as an active component. CONSTITUTION:The objective agent contains, as an active component, a compound of formula I [A is OH, OC(O)CH3-nXn (X is F, Cl, Br, methyl, etc.; n is 0-3), etc.; B is H or together with A form a bond; when R is H, R is H, C(Z)CH3-nXn (Z is O or S) or C(Z)NHCH3-nXn and, when R is not H, R and R together form (CH2)m (m is 4 or 5); R and R are H, 1-4C alkyl, etc.], a compound of formula II, etc., or its pharmaceutically permissible salt when the above compound can form a salt. The active component is preferably administered at a daily dose of 0.01-10mg in one or several divided doses.