The prevention of pain from injection of rocuronium by magnesium sulphate, lignocaine, sodium bicarbonate and alfentanil.

We compared the efficacy of magnesium sulphate, lignocaine, sodium bicarbonate or alfentanil in minimizing pain due to injection of rocuronium in 250 patients. After tourniquet application on the forearm, the patients were given saline, magnesium sulphate, lignocaine, sodium bicarbonate 8.4% or alfentanil, diluted into a 3 ml solution. The occlusion was released after 20 seconds, and rocuronium was injected over 10 to 15 seconds. The patients were observed and asked immediately if they had pain in the arm and the response was assessed. Reactions such as discomfort and pain, withdrawal of the hand and screaming after the administering of the rocuronium were recorded as side-effects and patients were reassessed at 24 hours postoperatively. We concluded that magnesium sulphate, lignocaine, sodium bicarbonate or alfentanil decreased the level of rocuronium injection pain. Of these drugs, magnesium sulphate, lignocaine and sodium bicarbonate were the most effective while alfentanil was the least effective.