Postoperative nausea and vomiting (PONV) remains a significant challenge in perioperative care, often leading to prolonged hospital stays and decreased patient satisfaction. The use of anti-emetics in the preoperative or postoperative periods aims to minimize PONV, but the optimal timing remains a subject of study. Both approaches offer distinct advantages, and what treatment regimen is best is influenced by the patient profile, the type of surgery, and the specific antiemetic used.
Preoperative administration of anti-emetics is favored for its preventive potential, especially in high-risk patients. Administering drugs such as dexamethasone or ondansetron prior to induction of anesthesia can preemptively block the pathways responsible for nausea and vomiting. Studies suggest that preoperative administration of the anti-emetic dexamethasone significantly reduces the incidence of PONV compared to postoperative administration, particularly in procedures known to be at high risk for PONV, such as gastrointestinal and gynecologic surgery (1). In addition, preoperative dexamethasone has been shown to be effective in reducing postoperative pain, contributing to better overall recovery outcomes (2).
In contrast, postoperative administration is often used as a reactive strategy to treat nausea and vomiting once it has occurred. This approach is particularly useful in cases where the patient’s risk factors for PONV were not initially apparent or when the duration of surgery exceeds predictions. A randomized controlled trial comparing preoperative and postoperative administration of ondansetron as an anti-emetic found that postoperative administration was slightly more effective in cases where nausea manifested after emergence from anesthesia (3).
One of the critical considerations in the timing of antiemetic administration is the pharmacokinetics of the chosen drug. For example, ondansetron has a short half-life and is most effective when administered close to the time of emetogenic stimuli, such as extubation or the immediate postoperative period. Conversely, dexamethasone, with its longer duration of action, shows optimal results when administered preoperatively as part of a multimodal antiemetic regimen (2).
While both approaches may be effective, combining preoperative and postoperative anti-emetics has been proposed as a strategy to maximize efficacy. This dual approach may be particularly beneficial in patients with multiple risk factors for PONV, such as a history of motion sickness, non-smoking status, or use of volatile anesthetics. In a study of colorectal surgery, a combination of preoperative dexamethasone and postoperative ondansetron resulted in significantly lower rates of PONV compared to either strategy alone (3).
However, the choice between preoperative and postoperative administration is also influenced by the side effect profile of the drugs used. Preoperative dexamethasone may increase blood glucose levels, which could be detrimental in diabetic patients, while postoperative ondansetron has been associated with headache and constipation. Therefore, patient-specific factors must always guide the decision-making process.
Enhanced Recovery After Surgery (ERAS) protocols increasingly emphasize preoperative antiemetic use as part of a proactive approach to PONV prevention. These protocols recommend preoperative administration because it is consistent with the goal of minimizing postoperative discomfort and reducing length of hospital stay (4). However, despite these recommendations, real-world application often requires individualized consideration, especially in patients undergoing long or complex procedures.
In conclusion, both preoperative and postoperative anti-emetics play a critical role in the management of PONV. Preoperative administration offers the advantage of prophylaxis, particularly with agents such as dexamethasone, while postoperative administration of agents such as ondansetron may better manage nausea when it becomes clinically evident. A combination approach may be optimal for high-risk patients. Ultimately, tailoring antiemetic strategies based on the patient’s risk profile, surgical factors, and drug characteristics is essential for effective management of PONV.
References
- deGraft-Johnson PKG, Djagbletey R, Baddoo HK, et al. Safety and efficacy of single-dose preoperative intravenous dexamethasone on post-operative nausea and vomiting following breast surgery at Korle-Bu Teaching Hospital. Ghana Med J. 2020;54(4):207-214. doi:10.4314/gmj.v54i4.2
- Kluger MT, Skarin M, Collier J, et al. Steroids to reduce the impact on delirium (STRIDE): a double-blind, randomised, placebo-controlled feasibility trial of pre-operative dexamethasone in people with hip fracture. Anaesthesia. 2021;76(8):1031-1041. doi:10.1111/anae.15465
- Holder-Murray J, Esper SA, Boisen ML, et al. Postoperative nausea and vomiting in patients undergoing colorectal surgery within an institutional enhanced recovery after surgery protocol: comparison of two prophylactic antiemetic regimens. Korean J Anesthesiol. 2019;72(4):344-350. doi:10.4097/kja.d.18.00355
- Shan X, Yang Y, Xiao X, et al. Enhanced efficacy of aprepitant-based triple prophylaxis in preventing postoperative nausea and vomiting following metabolic bariatric surgery: a single-center, retrospective cohort study. Front Med (Lausanne). 2025;12:1481720. Published 2025 Feb 17. doi:10.3389/fmed.2025.1481720