ALFENTANIL-MEDIATED ANALGESIA DURING PROPOFOL INJECTION - NO EVIDENCEFOR A PERIPHERAL ACTION

We have investigated if alfentanil acts via peripheral opioid receptor s to relieve the pain which occurs on injection of propofol. Thirty se conds before induction of anaesthesia and immediately after a tourniqu et at 50 mm Hg greater than systolic pressure was inflated on the uppe r arm, patients were given either placebo (n = 22), alfentanil 1 mg (n = 22) or lignocaine 40 mg (n = 22) via an i.v. cannula in the dorsum of the hand. Pain during injection of propofol was assessed using a th ree-point verbal rating scale, recorded at 8-s intervals. We found a s ignificant reduction in pain after lignocaine compared with the two ot her groups (P < 0.001), but there was no difference between the placeb o and alfentanil groups. We conclude that alfentanil does not relieve pain on injection with propofol via an action on peripheral opioid rec eptors when alfentanil is limited to the forearm for 30 s before induc tion of anaesthesia.