Recommended Dosage of Scopolamine Patches for Motion Sickness
For motion sickness prevention, apply one transdermal scopolamine patch (1 mg/3 days) to the hairless area behind one ear at least 4 hours before the antiemetic effect is required, for use up to 3 days. 1
Dosing Details and Administration
- Each scopolamine transdermal system is formulated to deliver approximately 1 mg of scopolamine over 3 days 1
- The patch contains a priming dose (140 μg) in the adhesive layer to accelerate achievement of steady-state blood levels, with the remainder released at a constant rate of approximately 5 μg/hour 2
- Apply the patch to the hairless area behind one ear on clean, dry skin 1
- For optimal effectiveness, apply the patch 6-8 hours before exposure to motion, as protective plasma concentrations (estimated at 50 pg/mL) are achieved after approximately 6 hours 2
- Steady-state plasma concentration of about 100 pg/mL is achieved 8-12 hours after application 2
- For faster protection, the patch may be applied 1 hour before the journey in combination with oral scopolamine (0.3 or 0.6 mg) 2
Duration and Replacement
- If motion sickness prevention is needed for longer than 3 days, remove the first patch and apply a new one behind the other ear 1
- After removal, fold the used patch in half with the sticky side together and discard properly to prevent accidental contact or ingestion 1
- Wash hands thoroughly with soap and water after applying or removing the patch 1
Efficacy
- Transdermal scopolamine has been shown to reduce the incidence and severity of motion sickness by 60-80% compared to placebo 2
- It is more effective than oral meclizine or cinnarizine, and similar in efficacy to oral scopolamine 0.6 mg or promethazine plus ephedrine 2, 3
- Studies at sea demonstrated that transdermal scopolamine provided protection against motion sickness at a significance level of p = 0.0001 compared to placebo 4
Important Precautions and Side Effects
- Only wear one transdermal system at any time; using two patches does not improve efficacy but increases adverse effects 2
- Common side effects include dry mouth (50-60% of users), drowsiness (up to 20%), and allergic contact dermatitis (10%) 2
- Transient impairment of ocular accommodation may occur, particularly in hypermetropic individuals 5
- Central nervous system effects may include reduced memory for new information, impaired attention, and lowered feelings of alertness 5
- Scopolamine is contraindicated in patients with angle closure glaucoma 1
- Neuropsychiatric adverse reactions may occur, including exacerbation of psychosis, agitation, speech disorder, hallucinations, paranoia, and delusions 1
- Elderly patients may be more sensitive to the neurological and psychiatric effects 1
Clinical Pearls
- Transdermal scopolamine is most effective against motion sickness 8-12 hours after application 2
- Approximately 20-30% of subjects may fail to attain the estimated protective concentration, which may explain some treatment failures 2
- The patch is particularly useful for long journeys (6-12 hours or longer) to avoid repeated oral doses 2
- Avoid touching or applying pressure to the patch while it is being worn, as this may cause scopolamine to ooze out at the edge 1
- Do not cut the transdermal system 1