Enzyme inhibitor

Indazoles of Formula (I) (I) in which R1, R2, R3 and R4 are each separately selected from hydrogen, halogeno, halogenoalkyl, formyl, carboxy, sulpho, cyano, nitro, COR and +NRR'R'' groups, wherein R, R' and R'' are each separately alkyl, aralkyl or aryl groups, and R5 is selected from hydrogen, halogeno, halogenoalky, formyl, carboxy, sulpho, cyano, nitro, hydroxy, alkoxy, alkyl, COR, NHCOR and +NRR'R'' groups, wherein R, R' and R'' are each separately alkyl, aralkyl or aryl groups, which may optionally be in the form of a physiologically acceptable ester or salt, are of value for use as an analgesic or in the treatment of any condition where the inhibition of brain/spinal cord nitric oxide synthase is advantageous, for example in neurodegenerative disease.