Comparison of cardiovascular responses after injection of lidocaine with either clonidine or adrenaline: a two-year comparative analysis

Our aim was to evaluate the efficacy of clonidine with lidocaine as a local anaesthetic agent for inferior alveolar mandibular nerve blocks for dental extraction. We studied 200 patients who required extraction of mandibular teeth and divided them into two groups of 100 each, the first of which was given lidocaine and adrenaline (12.5 μg/ml) and the second lidocaine and clonidine (15 μg/ml). Cardiovascular vascular variables (blood pressure, heart rate, and mean arterial pressure) were assessed before, during, and after extraction, and postoperative pain was measured on a visual analogue scale. There was a significant reduction in systolic blood pressure (p = 0.0001) and heart rate (p = 0.000) after injection of clonidine. However, they both increased after injections of lidocaine plus adrenaline, and there was a significant reduction in pain at four hours postoperatively with clonidine (p = 0.000). Our results showed that anaesthesia with lidocaine and clonidine decreases systolic blood pressure and heart rate 10 minutes after injection for extraction of lower mandibular teeth. We suggest that patients who have local anaesthetic with lidocaine and clonidine are at minimal cardiovascular risk and there is no difference in the onset of anaesthesia.