A comparative study of clinical efficacy of pretreatment between intravenous Granisetron and intravenous Lignocaine to allaevate pain on Propofol injection during general anaesthesia.

Propofol, a non-opioid intravenous anaesthetic agent, is frequently used as an inducing agent in general anaesthesia. Direct irritant effect of propofol on vein and kinin cascade release causes the pain in 30%-90% of the patients during intravenous injection (IV) though its pH and osmolality are close to those of blood.1,2

The American anaesthesiogist had ranked pain induced by propofol injection as the 7th most common problem of current clinical anaesthesiology.3 Various methods have been tried for attenuating pain during i.v. injection of propofol. Non pharmacological methods like injection in a fast running i.v. fluid, injection in a larger vein, diluting with 10% intra lipid, cooling propofol to 4°C have been tried with little success.4,5

Amongst pharmacological methods pre-treatment with several agents have been tried like lignocaine, fentanyl, ketamine, dexamethasone, dexmetomidine, clonidine, ketoprofen, tramadol.6-9

But, Neither a single agent nor any method is found till date that has 100% efficacy to relieve the pain of propofol injection. Pretreatment with IV lignocaine has proven to be efficacious, by reducing propofol induced pain by nearly 50-60% but is associated with paresthesia that lasts far beyond the duration of anesthesia, sensations of numbness, swelling, tingling, and itching.2

Injection pain is not only a cause of concern but, Post Operative Nausea and Vomiting (PONV) incidences are also high in patients undergoing general surgeries.10, 11 Other peri-operative factors like haemodynamic stability, analgesia andreduced adverse effects to drugs administered are subject of interest to anesthesiologists for better patient care who undergo surgery under general anaesthesia.

In this context, new pharmacological agents like 5HT3 receptor antagonists (ondansetron) have been tried to preventpain on IV propofol injection along with added benefit of preventing PONV, analgesia and reduced parasthesia.12Granisetron, a higher congener of ondansetron, has betterantiemetic effect. The preliminary evidence suggests that granisetron is effective in preventing pain on IV propofol administration by multifaceted activities such as a sodium channel blocker and μ opioid agonist apart from 5HT3 receptor antagonist activity. 10,13,14

 In our practice, 5HT3antagonists like ondensetron and granisetronis routinely administeredas pre-medication to prevent post-operative nausea and vomiting in patients undergoing surgeries under general anaesthesia.

Hence, in this study we want to compare the analgesic efficacy between IV granisetron (2mg in 2 ml) and IV lignocaine 2% (40mg in 2 ml) in allevating pain on IV propofol injection.