Reduction of pain on injection of propofol: combination of nitroglycerin and lidocaine

Purpose

Pain on propofol injection is a common adverse effect. This study examined the effect of a combination of nitroglycerin and lidocaine on pain during propofol injection compared to lidocaine alone.

Methods

In a double-blind, prospective trial, 90 patients scheduled to undergo elective plastic surgery were allocated randomly to three groups, to receive lidocaine 20?mg (n?=?30), a combination of lidocaine 20?mg and nitroglycerin 0.1?μg/kg (n?=?30), or normal saline as a placebo (n?=?30), with venous occlusion for 1?min, followed by the administration of 25?% of the total calculated dose of propofol (2?mg/kg) into a dorsal hand vein. The pain intensity during the propofol injection was assessed using a four-point scale (0?=?none, 1?=?mild, 2?=?moderate, 3?=?severe). Hemodynamic variables–mean arterial pressure and heart rate–were measured during the preoperative and intraoperative periods.

Results

A significantly higher proportion of patients in the placebo group (83?%) experienced pain compared to the lidocaine and combination groups (43 and 7?%, respectively; both, P?P?P?Conclusion A combination of nitroglycerin 0.1?μg/kg and lidocaine 20?mg with venous occlusion for 1?min was more effective than lidocaine 20?mg alone in decreasing pain during propofol injection.