Comparison of ondansetron-olanzapine combination with ondansetron alone for PONV prophylaxis in patients scheduled for laparoscopic cholecystectomy: A Randomized Controlled Study

Study Title: Comparison of ondansetron-olanzapine combination with ondansetron alone for PONV prophylaxis in patients scheduled for laparoscopic cholecystectomy: A Randomized Controlled Study

 Rationale: Post operative nausea and vomiting is a distressing complication following surgery. The incidence of PONV is as high 50-70% in laparoscopic cholecystectomy surgeries. Ondansetron 4mg iv has been used to prevent PONV after laparoscopic cholecystectomies, but in 22% patients, PONV is still seen even after use of ondansetron. Olanzapine has been used to prevent and treat nausea and vomiting in patients undergoing chemotherapy. Moreover, synergism is a known phenomenon when a combination of drugs is used. Review of literature did not reveal any study comparing the efficacy of combination of ondansetron and olanzapine with ondansetron alone for PONV prophylaxis in laparoscopic cholecystectomy surgeries.

**AIM:**To compare the efficacy of ondansetron-olanzapine combination with ondansetron alone for PONV prophylaxis in patients scheduled for laparoscopic cholecystectomy

OBJECTIVES: To compare the efficacy of ondansetron-olanzapine combination with ondansetron alone for PONV prophylaxis in terms of:

Primary:

Incidence of PONV in the initial 24 hrs after surgery

Secondary:

1.     Severity of PONV in the first 24 hr

2. Total requirement of rescue antiemetic in the first 24 hr
3. Incidence of drug-related side effects, if any.

Materials and method

SETTING: Department of Anaesthesiology and Critical Care

UCMS & G.T.B. Hospital, Delhi-95

Study design: Randomized Double - Blind study

Time frame: August 2025 – November 2026

 Participants:

Inclusion Criteria:

·       Patients aged >18 years, with ASA physical status I or II, undergoing laproscopic cholecystectomy for gallstone disease under GA

Exclusion Criteria :

·       Pregnant patients

·       Patients with cardiac, hepatic and renal disease

·       Patients with history of psychiatric disorder or currently on olanzapine.

·       Allergic to any drug used in study

·       Long term use of long acting antiemetics, emetogenic drugs, opioids, glucocorticoids or cancer chemotherapy.

Primary outcome

Incidence of PONV in the initial 24 hrs after surgery

Secondary outcome

1.     Severity of PONV in the first 24 hr

2. Total requirement of rescue antiemetic in the first 24 hr
3. Incidence of drug-related side effects, if any

ALLOCATION

Patients will be randomly allocated into:

Group T (n=51) – Patients will receive Olanzapine 5 mg orally (2 hrs before surgery) and Ondansetron 4 mg i.v (given near the end of surgery)

Group C (n=51)- Patients will receive Ondansetron 4mg i.v. (given near the end of the surgery)

Randomization will be done using computer-generated random number tables. The allocation concealment will be done using sequentially numbered opaque-coloured sealed envelopes. The study drug will be prepared by the third person not involved in the study.

Statistical analysis:

Categorical variables will be compared using the chi-square test or fisher’s exact test. Continuous variables will be compared using independent t-test. P- value less than 0.05 will be considered statistically significant.