What is the role of Scopolamine in the management of postoperative nausea (PONV)?

Role of Scopolamine in Managing Postoperative Nausea and Vomiting

Transdermal scopolamine is an effective anticholinergic medication for preventing postoperative nausea and vomiting (PONV) and should be considered as part of a multimodal approach for patients at moderate to high risk of PONV. 1

Mechanism and Efficacy

Scopolamine is a selective competitive antagonist of muscarinic cholinergic receptors that works as an antiemetic at low serum concentrations 2. The transdermal delivery system (TDS) provides gradual release over 72 hours following an initial bolus, making it particularly effective for PONV prevention:

• Significantly reduces the risk of postoperative nausea (RR=0.59,95% CI, 0.48-0.73)
• Significantly reduces the risk of postoperative vomiting (RR=0.68,95% CI, 0.61-0.76)
• Significantly reduces overall PONV (RR=0.73,95% CI, 0.60-0.88) in the first 24 hours after anesthesia 3

FDA-Approved Indications

Scopolamine transdermal system is specifically FDA-approved for:

• Prevention of nausea and vomiting associated with motion sickness
• Prevention of PONV associated with recovery from anesthesia and/or opiate analgesia and surgery 4

Dosing and Administration

For PONV prevention in surgeries other than cesarean section:

• Apply one transdermal patch (1 mg/3 days) behind the ear the evening before surgery
• Remove 24 hours following surgery 4

Risk-Based Approach to PONV Management

Scopolamine should be incorporated into a risk-based prophylaxis approach based on the Apfel Score, which considers:

• Female gender
• Non-smoking status
• History of PONV or motion sickness
• Expected postoperative opioid use 1

Based on risk factors:

• 0-1 risk factors: Consider single antiemetic
• 1-2 risk factors: Two-drug combination
• ≥2 risk factors: Three-drug combination 1

Combination Therapy

Scopolamine is particularly effective when used as part of a multimodal approach:

• The combination of transdermal scopolamine plus ondansetron is more effective than ondansetron alone for reducing PONV in outpatient settings 5
• When combined with ondansetron, scopolamine significantly improves complete antiemetic response (48% vs 39%, p<0.02) and total response (no nausea, no vomiting/retching, no rescue medication) (35% vs 25%, p<0.01) 5

Timing of Administration

Scopolamine is effective when applied:

• The night before surgery (early application) (RR=0.56; 95% CI, 0.41-0.75)
• On the day of surgery (late application) (RR=0.61; 95% CI, 0.47-0.79) 3

Adverse Effects

Common adverse effects include:

• Dry mouth (most common)
• Drowsiness
• Blurred vision and dilation of pupils
• Visual disturbances (RR=3.35; 95% CI, 1.78-6.32) 4, 3

Contraindications

Scopolamine is contraindicated in patients with:

• Angle closure glaucoma
• Hypersensitivity to scopolamine or other belladonna alkaloids 4

Special Considerations

• Monitor for increased intraocular pressure in patients with open-angle glaucoma
• Use with caution in patients with neuropsychiatric conditions as it may cause psychiatric and cognitive effects
• Avoid in pregnant women with severe preeclampsia due to risk of eclamptic seizures
• Consider more frequent monitoring in patients with gastrointestinal or urinary disorders 4

Place in PONV Management Algorithm

1. First-line prophylaxis options:

   • For moderate-risk patients: Scopolamine + one other agent (e.g., dexamethasone)
   • For high-risk patients: Scopolamine + two other agents from different classes (e.g., ondansetron and dexamethasone) 1

2. Rescue therapy:

   • If scopolamine was used for prophylaxis, choose a rescue agent from a different class
   • If scopolamine was not used for prophylaxis, it can be considered as rescue therapy 1

Scopolamine's long duration of action (up to 72 hours) makes it particularly valuable for preventing postoperative discharge nausea and vomiting, addressing a common cause of unplanned hospital readmission 6.