Blockade of the antinociception induced by diclofenac, but not of indomethacin, by sulfonylureas and biguanides

► Diclofenac and indomethacin produce antinociception in the rat formalin test. ► Sulfonylureas and biguanides block the diclofenac-induced antinociception. ►Sulfonylureas and biguanides do not block the indomethacin-induced antinociception. ► Diclofenac, but not indomethacin, produces antinociception activating K+ channels. ► Diclofenac produces antinociception activating biguanides-induced mechanisms. ► Indomethacin does not activate biguanides-induced mechanisms.