DRUG HAVING ERYTHROCYTE COAGULATION INHIBITOR

PURPOSE: To obtain a drug containing a specific compound such as a dihydropyrrolo-benzimidazole derivative. CONSTITUTION: This drug contains a compound of formula I [R1 is a group of formula II (R2 to R4 are each H, an alkanesulfonyloxy, an alkanesulfonylamino, an alkylsulfonylmethyl, hydroxycarbonyl, etc.), a 5-membered heterocyclic group or a 6-membered heterocyclic group; X is a bond (R1 may be H, an alkyl, an alkenyl, etc.), an alkylene or vinylene; A is N or CR5 (R5 is H, an alkyl, CN, an aryl, etc.); B is O, S, NR6 (R6 is H or an alkyl), etc.], e.g. 7,7-dimethyl-2-(4-pyridyl)-6,7-dihydro-3H,5H-pyrrolo[2,3-f]benzimidazo l-6- one.4H2 O. The drug is used for the treatment of the blood circulation disorder of the peripheral, coronary or cerebral vessel, shock, degenerative blood vessel diseases, rheumatic diseases, ulcer, tumor of gangrenous stage, degenerative disorder of retina, nerve or muscle, etc.