Least sedating benzodiazepine
Cholinergic agonists that do not cross into the brain such as neostigmine, do not produce motion sickness. Addiction to the patch can be managed by withdrawall, sometimes facilitated by use of oral agents containing hyocyamine. While the precise role of histamine in central vestibular processing is uncertain, there are data indicating that centrally acting antihistamines prevent motion sickness and reduce the severity of its symptoms even if taken after the onset of symptoms (Takeda et al, 1989).
It is to be hoped that agents selective for vestibular subtypes of muscarinic receptors will eventually be developed or discovered among our presently available pharmacopoeia, as these agents may provide vestibular suppression with less side effects. This has been described for scopolamine (Luetje and Wooten 1996), and other anticholinergics may also have addiction syndromes. All the antihistamines in general use for control of vertigo also have anticholinergic activity.
scopolamine) is better than any other ACH antagonist (e.g.
meclizine, hyocyamine, and many other antihistamines), but scopolamine has no central antihistamine component (which is associated with sleepiness and weight gain).
The term "vestibular suppressant" is a vague one generally used to indicate drugs that reduce nystagmus evoked by a vestibular imbalance or which reduce motion sickness.
There is evidence for involvement of several types of histamine receptors.
Serafin and others (1993) reported that histamine increases firing in MVN cells, mediated through the H2 receptor.
which affect muscarinic receptors, such as scopolamine, increase motion tolerance.
The action appears to be mainly central, although there are receptors in both the periphery and centrally.