The Effects of Lidocaine with Epinephrine on Bupivacaine-Induced Cardiotoxicity

Bupivacaine, a local anaesthetic substance, is used as a regional-anaesthesia agent. Lidocaine, a sodium channel blocker, is used in combination with epinephrine for regional anaesthesia. We aimed to evaluate the effects of lidocaine with epinephrine (LE) at different doses on bupivacaine-induced cardiotoxicity in rats.

In our study, 24 Wistar albino rats were divided into four groups: I) Control; II) LE, 1 mg kg^-1; III) LE, 3 mg kg^-1 and IV) LE, 6 mg kg^-1. Intravenous bupivacaine was administered at a dose of 3 mg kg^-1 min^-1 to the anaesthetized rats in all groups until cardiac asystole was achieved. LE was administered at the doses of 1, 3 and 6 mg kg^-1 min^-1 using infusion, simultaneously with bupivacaine. The asystole time and 75% decrement time in mean arterial blood pressure (MABP) were determined. P-Q, Q-T and QRS intervals were measured using electrocardiography (ECG) recordings.

LE significantly increased the asystole time and 75% decrement time in MABP at the doses of 3 and 6 mg kg^-1 compared to the control group (p<0.05) and significantly increased these values at the dose of 1 mg kg^-1 compared to the control and other treatment groups (p<0.05). LE abolished the prolongation of P-Q, Q-T and QRS intervals in ECG recordings at the dose of 1 mg kg^-1 (p<0.05).

These results reveal that LE has a protective effect against bupivacaine cardiotoxicity. In clinical application, the simultaneous application of LE and bupivacaine may reduce the risk of cardiotoxicity due to bupivacaine.