Bupivacaine binds with Na channels more strongly than lidocaine. This is due to its high protein binding character. It dissociates with Na channels very slowly that is why it is called as Fast In Slow Out Drug. while lidocaine shows fast in fast out features. Studies have shown that myocardial uptake of bupivacaine is greater as compared to lidocaine, as a result, it has the potential to cause severe cardiac arrhythmias similar to torsos de pointese.
Fatal ventricular fibrillation is seen with bupivacaine but not with lidocaine or tetracaine. Factors affecting cardiotoxicity of Bupivacaine: 1. Pregnancy- pregnant patients are more susceptible to Cardiotoxicity of local anaesthetic due to prolonged rise in progesterone levels. It has been suggested that progesterone increases the tissue sensitivity for local anaesthetic. Moreover, free drug levels are increased in pregnancy due to…
