"
Trikatu"-an Ayurvedic formulation comprising of a 1:1:1 ratio of dried fruits of Piper nigrum, Piper longum and dried rhizomes of Zingiber officinale is widely used to enhance the bioavailability of drugs, like
vasicine,
indomethacin, etc. The enhanced
biological response might lead to alteration of therapeutic regimens of commonly prescribed drugs. The present work was aimed to study the effect of concomitant administration of
Trikatu on the pharmacokinetics and pharmacodynamics of
diclofenac sodium, a frequently prescribed non-steroidal anti-inflammatory
drug, having a poor oral bioavailability (54 +/- 2%). The effect of
Trikatu on the bioavailability profile of
diclofenac sodium was studied in rabbits. It was observed that
Trikatu significantly decreased the serum levels of
diclofenac sodium. The pharmacodynamic study was carried out to evaluate the effect of
Trikatu on the anti-inflammatory activity of
diclofenac sodium using carragenin-induced rat paw
edema model. It was observed that the mean percent
edema inhibition shown by the combination of
Trikatu and
diclofenac was similar to that shown by
Trikatu alone but significantly less than that shown by
diclofenac alone. Thus, the experimental findings indicated that
Trikatu pretreatment might decrease the bioavailability of certain drugs probably through a drug-herb interaction thereby adversely affecting the therapeutic efficacy of these drugs.