5 HT3 antagonists
Background
Distressing symptoms like Postoperative nausea and vomiting (PONV) commonly occur after laparoscopic surgeries under general anesthesia (Kannan S et al. 2019). PONV is said to have a multifactorial etiology. Shirin S et al. 2019 observed that reduced morbidity is associated with cholecystectomy by laparoscopic surgery (An accepted procedure for symptomatic cholelithiasis). But this procedure has increased the incidence of PONV(53-72%) (Milnes V et al. 2015). Carbon dioxide insufflation led to the dilatation of intentional loops and observed as a risk factor for nausea and vomiting after laparoscopic surgery. After the stimulation of gut wall-associated mechanoreceptors, serotonin is synthesized, which triggers the medulla’s chemoreceptors, and finally, vagus nerve terminals are activated and evoke an emetic response (Fujii Y et al. 2011).
Granisetron is first-generation, non-competitive, 5 HT3 antagonists. It is superior over tropisetron and does not affect the activity of hepatic enzymes in-vitro (Leowen et al. 2000). It is used as an anti-emetic drug ( Wilson et al. 1996). It acts directly on enterochromaffin cells and acts solely through 5 HT3 receptors on vagal afferents. It crosses the placental membrane in a dose-dependent manner ( Edwin et al. 2019). It is administered with various routes.it has similar efficacy compared to other first-generation 5- HT3 antagonists (tropisetron, ondansetron, and dolasetron).
Ondansetron is also a first selective 5 HT antagonist and safest effective anti-emetic agents. It has a similar mechanism of action with granisetron (Anh L Ngo et al. 2019 & Ahmet A et al. 2019). It affects the vagus nerve terminals where 5-HT-3 are present. It is well known that the vagus nerve is responsible for the triggering of nausea and vomiting, and this drug is metabolized with the help of cytochrome P450 present in the liver (Patel P et al. 2019).
It is suggested that the selection of both drugs over the other be based on comparison bases for the prevention of postoperative nausea and vomiting in patients undergoing laparoscopic cholecystectomy under general anesthesia.
Therefore, we conducted a study to compare the efficacy of the 5- HT3 antagonists i.e., granisetron against ondansetron, that has proven to be an effective and safest drug in preventing nausea and vomiting after laparoscopic cholecystectomy. This study aims to compare Ondansetron with Granisetron in preventing postoperative nausea and vomiting in patients undergoing laparoscopic cholecystectomy under General anesthesia.