What are some problems a diver may encounter while taking motion sickness medications?

Many divers opt to take medication to relieve the symptoms of motion sickness associated with boat travel.  Divers that take anti-histamines such as Dramamine may experience drowsiness, lack of judgment and an increased risk of nitrogen narcosis. Divers that opt for a patch containing scopolamine may cause dilated pupils, dry mouth, and if taken in high doses it has been known to cause disorientation; even with such side effects, the patch is preferred by more divers than Dramamine and other anti-histamines.