What is more effective for postoperative nausea, Ondansetron (Zofran) or Scopolamine (transdermal patch)?

From the Guidelines

Zofran (ondansetron) is generally considered more effective for immediate post-operative nausea, while scopolamine patches are more effective for prevention of post-operative nausea and vomiting (PONV) in high-risk patients or when nausea is expected to last longer than 24 hours. The choice between Zofran and scopolamine patches depends on the specific patient and situation. Zofran works by blocking serotonin receptors in the brain and gut that trigger nausea, and is typically given as 4mg IV every 8 hours as needed 1. Scopolamine patches (1.5mg, applied behind the ear 2-4 hours before surgery) block acetylcholine receptors and are effective for up to 72 hours 1.

Comparison of Zofran and Scopolamine Patches

• Zofran has a quicker onset but shorter duration, while scopolamine patches have a slower onset but longer-lasting effects
• Side effect profiles differ: Zofran may cause headache or constipation, while scopolamine can cause dry mouth, blurred vision, and occasionally confusion, particularly in elderly patients
• For most routine surgeries, Zofran is the first-line treatment, but combining both medications may provide better control for high-risk patients 1

Recommendations for Post-Operative Nausea and Vomiting (PONV) Prophylaxis

• All patients should have a risk assessment for PONV using a scoring system such as the Apfel score 1
• Patients with a score of 1 should receive a combination of two drugs using first-line antiemetics as prophylaxis
• Patients with a score of 2 or more should receive 2-3 antiemetics
• Additional measures to reduce PONV include total intravenous anesthesia (TIVA) rather than volatile gases and multimodal analgesia rather than the liberal use of opioids 1

From the Research

Comparison of Zofran and Scopolamine Patch for Post-Op Nausea

• The effectiveness of Zofran (ondansetron) and scopolamine patch for preventing postoperative nausea and vomiting (PONV) has been studied in various clinical trials 2, 3, 4, 5.
• A study published in 2020 found that ondansetron, the active ingredient in Zofran, was effective in reducing vomiting within 24 hours postoperatively, with a risk ratio of 0.55 (95% CI 0.51 to 0.60) compared to placebo 3.
• Another study published in 2011 reviewed the clinical evidence regarding the safety and efficacy of a fixed-dose combination of ondansetron and transdermal scopolamine for preventing PONV in adolescent patients, but did not provide a direct comparison with Zofran alone 2.
• A 1997 systematic review of ondansetron for treatment of established postoperative nausea and vomiting found that all doses of ondansetron (1 mg, 4 mg, and 8 mg) were more efficacious than placebo in preventing further episodes of nausea or vomiting, with no significant differences between doses 4.
• A 1991 randomized, double-blind study compared ondansetron with placebo for treatment of postoperative nausea and vomiting and found that ondansetron was effective in 78% of patients, while placebo was effective in 28% of patients 5.
• There is limited direct comparison between Zofran and scopolamine patch in the provided studies, but a 2020 network meta-analysis found that scopolamine was effective in reducing vomiting, although the certainty of evidence was low 3.

Efficacy of Zofran and Scopolamine Patch

• The efficacy of Zofran (ondansetron) in preventing PONV has been well established, with high-certainty evidence showing that it reduces vomiting within 24 hours postoperatively 3.
• The efficacy of scopolamine patch in preventing PONV has also been studied, although the certainty of evidence is lower compared to Zofran 3.
• The choice between Zofran and scopolamine patch may depend on individual patient factors, such as the type and duration of surgery, anesthesia, and personal preferences.

Safety and Side Effects

• The safety and side effects of Zofran (ondansetron) and scopolamine patch have been studied in various clinical trials 3, 4, 5.
• Common side effects of Zofran include headache, constipation, and dizziness 3, 4, 5.
• Scopolamine patch has been associated with side effects such as dry mouth, dizziness, and blurred vision 3.