Heterocyclic amidines with anti-inflammatory and analgesic activity that inhibit nitrogen oxide production, of formula (I): in which: G1 and G2 are hydrogen, halogen, hydroxyl, C1-C4 alkoxy, C1-C4 alkyl, and an amidino substituent of formula Q, provided that, for each compound of formula (I), only one of the two substituents G1 or G2 is an amidino substituent of formula Q: and in which the substituents W, Y and X are combined to form 9- or 10-membered bicyclic heteroaromatic derivatives containing up to 2 hetero atoms in the same ring; and Z is an aryl or heteroaryl group, a linear or branched C1-C6 alkyl or alkenyl chain, a C1-C4 alkyl-aryl group or a C1-C4 alkyl-heteroaryl group.