The effect of oral clonidine pretreatment on intraocular pressure and hemodynamic stability after succinylcholine injection and intubation in cataract surgery

Providing better surgical conditions with meticulous control of Intraocular Pressure (IOP) is one of the most important factors that affect the success rate in ophthalmic surgery. Clonidine is a selective central α2 agonist with analgesic, antianxiety and sedative effects which makes it a good choice in premedication recently. In this study, we compared the effects of oral clonidine with oral diazepam as premedicants on IOP and hemodynamic stability after injection of succinylcholine and intubation in cataract surgery. 109 patients with physical status 1-2 were randomly assigned in 2 groups. The C Group (54 cases) was treated with oral clonidine (3 mic/kg) and the D group (55 cases) was treated with oral diazepam (0.15 mg/kg), 2 hours before induction of anesthesia. Induction of general anesthesia in all patients was performed with sodium thiopental (5mg/kg), fontanel (2mic/kg) & succinylcholine (1.5mg/kg). Heart rate and mean arterial blood pressure were measured before and immediately after induction and 5 & 10 minutes after intravenous injection of succinylcholine. Measurements of IOP were performed before and 5 and10 minutes after injection of succinylcholine. IOPs’ were always lower in C group as compared with D group but the IOP difference between groups was only significant at 5 minutes after succinylcholine injection. Mean arterial blood pressure and pulse rate were lower in C group compared with D group and the most significant difference observed was at the time 5 minutes after succinylcholine injection. Small doses of oral clonidine as premedicant can effectively reduce the IOP and provide better hemodynamic stability after intravenous injection of succinylcholine and intubation in cataract surgery.