Grapefruit juice potentiates the anti-inflammatory effects of diclofenac on the carrageenan-induced rat's paw oedema.

The anti-inflammatory effect of diclofenac alone or in combination with double strength grapefruit juice was investigated on carrageenan-induced rat's paw oedema. Paw was measured by using a plethysmometer 3 h after injecting the phlogestic agent. There was significant inhibition (P< 0.05) of the oedematous response after oral administration of diclofenac alone (1, 2.5, 5 mg kg(-1)p.o.) in a dose-dependent manner. Coadministration of grapefruit juice (10 ml kg(-1)p.o.) orally with all doses of diclofenac, enhanced the inhibitory effect of diclofenac on rat's paw oedema. Double-strength grapefruit juice has synergistic inhibitory effect on rat's paw oedema when administered in combination with diclofenac. Copyright 2002 Academic Press.