Dimenhydrinate
Dimenhydrinate, sold under the brand name Dramamine, among others, is an over-the-counter drug used to treat motion sickness and nausea. Dimenhydrinate is a theoclate salt composed of diphenhydramine, an ethanolamine derivative, and 8-chlorotheophylline, a chlorinated theophylline derivative, in a 1∶1 ratio.

Medical uses
Nausea
Dimenhydrinate is an over-the-counter (OTC) antihistamine indicated for the prevention and relief of nausea and vomiting from a number of causes. It is an H1 receptor antagonist that demonstrates anticholinergic activity.

Medicinal chemistry
Diphenhydramine is the primary constituent of dimenhydrinate and dictates the primary effect. The main difference relative to pure diphenhydramine is a lower potency due to being combined with 8-chlorotheophylline. By weight, dimenhydrinate is between 53% to 55.5% diphenhydramine.

Side effects
Common side effects may include:
Drowsiness
Dry mouth, nose, or throat
Constipation
Blurred vision
Feeling restless or excited (especially in children)

Recreational use
Dimenhydrinate is recreationally used as a deliriant. Slang terms for Dramamine used this way include "drama", "dime", "dime tabs", "D-Q", "substance D", "d-house", and "drams". Abusing Dramamine is sometimes referred to as Dramatizing or "going a dime a dozen", a reference to the amount of Dramamine tablets generally necessary for a trip.Many users report a side-effect profile consistent with tropane alkaloid (e.g. atropine) poisoning as both show antagonism of muscarinic acetylcholine receptors in both the central and autonomic nervous system, which inhibits various signal transduction pathways.Other CNS effects occur within the limbic system and hippocampus, causing confusion and temporary amnesia due to decreased acetylcholine signaling. Toxicology also manifests in the autonomic nervous system, primarily at the neuromuscular junction, resulting in ataxia and extrapyramidal side effects and the feeling of heaviness in the legs, and at sympathetic post-ganglionic junctions, causing urinary retention, pupil dilation, tachycardia, irregular urination, and dry red skin caused by decreased exocrine gland secretions, and mucous membranes. Considerable overdosage can lead to myocardial infarction (heart attack), serious ventricular arrhythmias, coma, and death. Such a side effect profile is thought to give ethanolamine-class antihistamines a relatively low abuse liability. An antidote that can be used for dimenhydrinate poisoning is physostigmine.

Brand names
Dimenhydrinate is marketed under many brand names: in the US, Mexico, Turkey and Serbia as Dramamine; in Ukraine as Driminate; in Canada, Costa Rica, and India as Gravol; in Iceland as Gravamin; in Russia and Croatia as Dramina; in South Africa and Germany as Vomex; in Australia and Austria as Vertirosan; in Brazil as Dramin; in Colombia as Mareol; in Ecuador as Anautin; in Hungary as Daedalon; in Indonesia as Antimo; in Italy as Xamamina or Valontan; in Peru as Gravicoll; in Poland and Slovakia as Aviomarin; in Portugal as Viabom, Vomidrine, and Enjomin; in Spain as Biodramina; in Thailand as Daimenin; in Israel as Travamin; in Pakistan as Gravinate; and in Ethiopia as dimenhydrinate.

Popular culture
Modest Mouse produced a song titled "Dramamine" on their 1996 debut album This Is a Long Drive for Someone with Nothing to Think About. The song uses side effects of the drug as a metaphor for the deteriorating state of a personal relationship.

References
External links
 Media related to Dimenhydrinate at Wikimedia Commons
"Diphenhydramine". Drug Information Portal. U.S. National Library of Medicine.
"8-Chlorotheophylline". Drug Information Portal. U.S. National Library of Medicine.