Effect of clonidine added to lidocaine for sub-Tenon’s (episcleral) anesthesia in cataract surgery

Abstract

We aimed to evaluate the duration of anesthesia, analgesia and ocular akinesia of clonidine added to lidocaine in sub-Tenon's anesthesia in patients undergoing cataract surgery. Forty patients were prospectively enrolled. They were randomized to two sub-Tenon's anesthesia groups: group L (6 ml of lidocaine 2 %, 1 ml of 0.9 % saline and 25 UI/ml of hyaluronidase), and group C (6 ml lidocaine 2 %, clonidine 1 μg/kg, 1 ml of 0.9 % saline and 25 UI/ml of hyaluronidase). Duration of sensory anesthesia, ocular akinesia in all directions, akinesia of the levator palpebrae superioris and orbicularis oculi muscles, the duration of analgesia (time to the first postoperative use of analgesics), the overall use of analgesics and the presence of adverse effects were recorded . The duration of sensory anesthesia and akinesia of the four rectus, levator palpebrae superioris, and orbicularis oculi muscles was significantly longer in group C (p < 0.05). The number of patients who required analgesics was similar between the groups but the duration of analgesia was longer in group C (p < 0.05). No significant adverse effects were observed. The addition of clonidine 1 μg/kg to 2 % lidocaine in sub-Tenon's anesthesia for cataract surgery increased the duration of sensory anesthesia, ocular akinesia, and the duration of analgesia.