Scopolamine Patches for Motion Sickness and Postoperative Nausea and Vomiting
Indications and Efficacy
Scopolamine transdermal patches are highly effective for prevention of both motion sickness and postoperative nausea and vomiting (PONV), with each patch delivering 1 mg of scopolamine over 3 days at a rate of approximately 5 μg/hour. 1
- Scopolamine is an anticholinergic agent that competitively inhibits muscarinic receptors, producing both peripheral antimuscarinic effects and central sedative, antiemetic, and amnestic effects 2
- For motion sickness, scopolamine is considered the most effective single agent for prevention 2
- For PONV, scopolamine patches have been shown to significantly reduce the risk of postoperative nausea (RR = 0.59), postoperative vomiting (RR = 0.68), and overall PONV (RR = 0.73) during the first 24 hours after anesthesia 3
Dosage and Administration
For Motion Sickness:
- Apply one transdermal patch to the hairless area behind one ear at least 4 hours before antiemetic effect is required 1
- For optimal protection, apply the patch 6-8 hours before the anticipated motion exposure 4
- For faster protection, the patch may be applied 1 hour before the journey in combination with oral scopolamine (0.3 or 0.6 mg) 4
- Each patch is effective for up to 3 days; if longer protection is needed, remove the first patch and apply a new one behind the other ear 1
For Postoperative Nausea and Vomiting:
- For surgeries other than cesarean section, apply one patch behind the ear the evening before surgery and remove 24 hours following surgery 1
- Scopolamine patches are effective for PONV prevention whether applied the night before surgery (early application) or on the day of surgery (late application) 3
Pharmacokinetics
- After application, the patch delivers a priming dose (140 μg) to quickly achieve steady-state blood levels 2, 4
- Peak plasma concentrations of approximately 100 pg/mL (range 11-240 pg/mL) are reached after about 8 hours 2
- The protective plasma concentration of scopolamine is estimated to be 50 pg/mL, which is typically achieved within 6 hours of application 4
- The transdermal system functions similarly to a 72-hour slow intravenous infusion 4
Adverse Effects
- Most common adverse effects for motion sickness (>15%): dry mouth, drowsiness, blurred vision, and dilation of the pupils 1
- Most common adverse effects for PONV (≥3%): dry mouth, dizziness, somnolence, agitation, visual impairment, confusion, mydriasis, and pharyngitis 1
- Visual disturbances are significantly more common with scopolamine patches compared to placebo (RR = 3.35) 3
- Scopolamine patches produce only about half the incidence of drowsiness caused by oral antihistamines like dimenhydrinate or cinnarizine 4
Contraindications and Warnings
- Contraindicated in patients with angle closure glaucoma 1
- Contraindicated in patients with hypersensitivity to scopolamine, other belladonna alkaloids, or any component of the formulation 1
- Use with caution in patients with:
- Avoid use in pregnant women with severe preeclampsia due to risk of eclamptic seizures 1
Special Considerations
- Only wear one transdermal system at a time (standard dosing) 1
- For patients who fail to respond to a single patch, a double-dose (two patches) may be considered in certain cases, as research has shown this increases plasma scopolamine concentration without significantly worsening adverse effects 5
- Wash hands thoroughly with soap and water after application to avoid accidental transfer to eyes, which can cause blurred vision 1
- Anticholinergic withdrawal symptoms may occur 24 hours or more after removal of the patch 1
Multimodal Approach for PONV
- Scopolamine patches can be effectively used as part of a multimodal approach to PONV prevention 6
- Combination regimens (such as 5-HT3 antagonists combined with either droperidol or dexamethasone) are significantly more effective than single agents alone 6
- A multimodal approach to nausea and vomiting prevention is becoming standard of care in surgical settings 6