Nitroparacetamol exhibits anti‐inflammatory and anti‐nociceptive activity

Nitroparacetamol (NCX‐701) is a newly synthesized nitric oxide‐releasing derivative of paracetamol. Following i.p. administration, nitroparacetamol inhibits carrageenan‐induced hindpaw oedema formation (ED 50 , 169.4 μmol kg −1 ) and mechanical hyperalgesia (ED 50 , 156 μmol kg −1 ) in the rat. In contrast, the parent compound, paracetamol, exhibits no significant anti‐oedema activity in this model (ED 50 >1986 μmol kg −1 , i.p.) and is markedly less potent than nitroparacetamol as an inhibitor of carrageenan‐mediated hyperalgesia (ED 50 , 411.6 μmol kg −1 , i.p.). In a second model of nociception (inhibition of acetic acid induced abdominal constrictions in the mouse), nitroparacetamol administered orally (ED 50 , 24.8 μmol kg −1 ), was again considerably more potent than paracetamol (ED 50 , 506 μmol kg −1 , p.o.). Thus, compared with paracetamol, nitroparacetamol not only exhibits augmented antinociceptive activity in both rat and mouse but, intriguingly, is also anti‐inflammatory over a similar dose range. British Journal of Pharmacology (2000) 130 , 1453–1456; doi: 10.1038/sj.bjp.0703509