The effect of tiaprofenic acid and indomethacin on vascular prostacyclin and platelet thromboxane A2 production.

Two experimental models were used to compare tiaprofenic acid and indomethacin. The first model involved assessing their effect on in vitro prostacyclin synthesis by rat aortic rings and human umbilical endothelial cells. The results showed that the inhibitory effect of the two drugs was similar. The second model involved assessing the effect of these drugs on in vitro thromboxane A2 release by human platelets. Indomethacin was shown to be a more potent inhibitor of TXA2 release than tiaprofenic acid, but this difference was only significant at low concentrations of the drugs; at concentrations equivalent to those achieved during routine treatment, both produced near maximal inhibition of TXA2 release by platelets. It is concluded that the findings do not support the claim that tiaprofenic acid is more 'selective' in its actions on these aspects of prostaglandin synthesis than another non-steroidal anti-inflammatory drug, indomethacin.