Potential anti-thrombotic effects of local anaesthetics due to their inhibition of platelet aggregation.

The aim was to study the possible anti-aggregating effects of local anaesthetics on platelets stimulated by physiological doses of adenosine-diphosphate and collagen. Platelet-rich plasma was therefore incubated in an aggregometer with lidocaine, bupivacaine or tocainide in various concentrations and for different incubation times. It was found that of the local anaesthetics tested, lidocaine was the most effective anti-aggregating compound. Furthermore, the longer the incubation time with the different local anaesthetics, the more efficient the anti-aggregating effect. These results may have clinical implications, and they may be one of the explanations for the lower incidence of thromboembolism in patients operated on under lumbar epidural anaesthesia.