Transdermal scopolamine: a review of its effects upon motion sickness, psychological performance, and physiological functioning.

Scopolamine is the most effective single drug for the prophylaxis and treatment of motion sickness. However, oral or injected scopolamine displays a comparatively short duration of action (5-6 hours), and leads to deleterious side effects on autonomic and central nervous system cholinergic functions. The transdermal scopolamine system was designed to reduce these problems, but while it does deliver scopolamine over a prolonged time period (72 h), deleterious side effects are also produced. Transdermal scopolamine provides significant motion sickness protection, similar in extent to that provided by oral scopolamine or dimenhydrinate. Its autonomic nervous system effects comprise reduced salivation, bradycardia, and blurred vision due to reduced visual accommodation. The visual problems increase following repeated patch applications, with hypermetropic ("long sighted") individuals particularly at risk. Central nervous system effects comprise reduced memory for new information, impaired attention, and lowered feelings of alertness. Variation in response to transdermal scopolamine has also been reported, both between individuals, and between different patch applications on the same individual.