Effects of ketorolac tromethamine (Toradol) on a functional model of microvascular thrombosis.

Ketorolac tromethamine (Toradol), a potent nonsteroidal anti-inflammatory drug used for postoperative pain, also strongly inhibits platelet aggregation. The anti-thrombotic effects of intramuscular ketorolac were assessed with a described rat model of microarterial thrombosis. After a single dose of ketorolac mean bleeding times were significantly prolonged (p < 0.01) and platelet aggregation was markedly reduced. Patency rates at 20 min were significantly higher in ketorolac groups compared to controls (p < 0.005). However, all vessels were thrombosed at 24 h. Scanning electron microscopy demonstrated decreased platelet aggregation and decreased thrombus formation in ketorolac treated animals at 20 min. The prolonged bleeding time and reduction in platelet aggregation add support to concerns of bleeding complications reported in patients treated with ketorolac perioperatively. Thus, ketorolac should probably not be used for pain relief in patients in whom postoperative haematoma formation is a particular concern. In addition, in this model, ketorolac as a single agent was ineffective for long-term prevention of microarterial thrombosis.