Circulatory disorder improving agent

A method for suppressing decrease in various organ blood flow volumes, which is associated with hypertension, comprising administering, for the purpose of suppressing decrease in various organ blood flow volumes, which is associated with hypertension, a pharmaceutically effective amount of a dihydropyridine compound of the formula (I) ##STR6## wherein R.sup.1, R.sup.2 and R.sup.3 are the same or different and each is an alkyl having 1-6 carbon atoms, a cycloalkyl having 3-6 carbon atoms or an alkoxyalkyl;

• R.sup.4 and R.sup.5 are the same or different and each is a hydrogen atom, an alkyl having 1-6 carbon atoms, a cycloalkyl having 3-6 carbon atoms, a halogenated alkyl, an alkylsufonyl, an alkylsulfinyl, an alkylthio, an alkoxy, a halogenated alkoxy, an alkoxycarbonyl, a cyano, a halogen or a nitro, provided that R.sup.4 and R.sup.5 are not hydrogen atoms at the same time;
• X is a vinylene or --CH.dbd.N--;
• A is an alkylene;
• and
• B is a group of the formula --N(R.sup.6)(R.sup.7) or ##STR7## wherein R.sup.6 and R.sup.7 and R.sup.8 are the same or different and each is a hydrogen atom, an alkyl having 1-6 carbon atoms, a cycloalkyl having 3-6 carbon atoms, a phenyl C.sub.1 -C.sub.3 alkyl, a phenyl, a naphthyl, or a pyridyl, Ar is a phenyl, a naphthyl or a pyridyl and n is an integer of 0, 1 or 2 or an acid addition salt thereof;
• and a pharmaceutically acceptable carrier.