Comparison of ondansetron or lignocaine pretreatment for reduction in pain due to propofol intravenous injection: Single blind randomized study

To reduce pain due to propofol injection, various drugs have been triedsuch as lignocaine, ketorolac, paracetamol, ketamine, magnesium sulfate ortopical nitroglycerine application but complete attenuation of pain due topropofol injection was not observed. Mixing lignocaine withpropofol is most commonly used method for prevention of propofol injection pain. Ondansetron is a selective serotonin receptor antagonist (5-HT3),currently used for the prophylaxis and treatment of postoperative nausea andvomiting. Some studies have demonstrated that ondansetron can produce localanesthetic effect, probably by blocking sodium channels. It blocks theperipheral nociceptive effect of serotonin thus having antinociceptive effect. Ondansetronbinds to the opioid μ receptors and acts as an agonist.Twocomparative studies between lignocaine and ondansetron have been carried out inIndia with variable results and they had recruited 40-50 patients.7,8 Routinely ondansetron is administeredpreoperatively to prevent post-operative nausea and vomiting. Therefore,instead of another drug, ondansetron will be compared with lignocaine to assessthe analgesic effect in larger number of individuals.