What is the use and application of the scopolamine (transdermal patch)?

Scopolamine Transdermal Patch: Uses and Application

The scopolamine transdermal patch is primarily indicated for the prevention of nausea and vomiting associated with motion sickness and for post-operative nausea and vomiting (PONV) following anesthesia and/or surgery. 1

Primary Indications

• Motion Sickness Prevention: The transdermal patch delivers approximately 1 mg of scopolamine over 3 days and should be applied at least 4 hours before the antiemetic effect is required 1
• Post-Operative Nausea and Vomiting (PONV): For surgeries other than cesarean section, apply one patch the evening before scheduled surgery and remove 24 hours following surgery 1
• Palliative Care: Used to reduce excessive secretions associated with dyspnea in palliative care settings 2
• Breakthrough Nausea and Vomiting: Can be used as a rescue medication for breakthrough nausea and vomiting when other antiemetics have failed 2

Application Instructions

• Placement: Apply to the hairless area behind one ear (postauricular area) 1
• Duration: Each patch is effective for up to 3 days 1, 3
• Handling:
  • Wash hands thoroughly with soap and water after application
  • Avoid touching or applying pressure to the patch once applied
  • Do not cut the patch
  • Only wear one patch at a time 1
• Removal: Fold used patch in half with sticky side together and discard properly to prevent accidental contact or ingestion 1

Pharmacokinetics

• Delivery System: Contains 1.5 mg of scopolamine with a priming dose (140 μg) in the adhesive layer to accelerate achievement of steady-state blood levels 3, 4
• Onset of Action: Reaches protective plasma concentration (50 pg/mL) after approximately 6 hours 3
• Steady State: Achieves steady-state plasma concentration of about 100 pg/mL at 8-12 hours after application 3, 4
• Duration: Maintains therapeutic levels for approximately 72 hours 3, 4

Efficacy

• Motion Sickness: Reduces incidence and severity by 60-80% compared to placebo 3, 5
• PONV: Significantly reduces risk of postoperative nausea (RR=0.59), vomiting (RR=0.68), and overall PONV (RR=0.73) in the first 24 hours after anesthesia 6
• Comparison to Other Antiemetics: More effective than oral meclizine or cinnarizine, similar to oral scopolamine 0.6 mg or promethazine plus ephedrine 3, 5

Adverse Effects

• Common Side Effects (>15% for motion sickness):

  • Dry mouth
  • Drowsiness
  • Blurred vision
  • Dilation of pupils 1, 5

• PONV-Related Side Effects (≥3%):

  • Dry mouth
  • Dizziness
  • Somnolence
  • Agitation
  • Visual impairment
  • Confusion 1

• Serious Adverse Effects:

  • Acute angle closure glaucoma (contraindicated in patients with angle closure glaucoma) 1
  • Neuropsychiatric reactions (particularly in elderly patients) 1
  • Urinary retention 1, 4

Special Considerations

• Contraindications:

  • Angle closure glaucoma
  • Hypersensitivity to scopolamine or other belladonna alkaloids 1

• Cautions:

  • Monitor intraocular pressure in patients with open-angle glaucoma 1
  • Use with caution in patients with intestinal obstruction, pyloric obstruction, or impeded urine flow 1
  • Not recommended for immediate use in imminently dying patients due to 12-hour onset of action 2

• Pregnancy: Should be administered to pregnant women only under observation 4

Alternative Applications

• Excessive Secretions in Palliative Care: Used to reduce secretions in end-of-life care, though glycopyrrolate may be preferred in some cases as it is less likely to cause delirium due to limited blood-brain barrier penetration 2

• Combination Therapy: For faster protection against motion sickness, the patch may be applied 1 hour before journey in combination with oral scopolamine (0.3 or 0.6 mg) 3

The scopolamine transdermal patch offers significant advantages over oral or parenteral administration, including extended duration of action and reduced incidence of side effects, making it particularly valuable for situations requiring prolonged antiemetic effect 3, 4.