Dimenhydrinate

Structural formula
General
Non-proprietary name	Dimenhydrinate
other names	(2-benzhydryloxyethyl) -dimethylammonium-8-chloro-1,3-dimethyl-3,7-dihydropurine-2,6-dione; Dramamines;
Molecular formula	C 24 H 28 ClN 5 O 3
External identifiers / databases
EC number	208-350-8
ECHA InfoCard	100.007.593
PubChem	10660
DrugBank	DB00985
Wikidata	Q420439
Drug information
ATC code	R06 AA02
Drug class	Antihistamine , antiemetic
Mechanism of action	Competitive antagonism to histamine at the H 1 receptor .
properties
Molar mass	469.96 g mol −1
safety instructions
	Please note the exemption from the labeling requirement for drugs, medical devices, cosmetics, food and animal feed
GHS labeling of hazardous substances Caution
H and P phrases	H: 302
	P: no P-phrases
Toxicological data	1320 mg kg −1 ( LD 50 , rat , oral )
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Dimenhydrinate is a salt made from diphenhydramine and 8-chloro theophylline and thus a combination of two active ingredients. Diphenhydramine is an H ₁ receptor antagonist ( 1st generation antihistamine ) and is mainly used as a remedy for nausea and vomiting ( antiemetic ) and as a sedative (sedative). Chlor theophylline is a mild stimulant and is added to reduce tiredness. Diphenhydramine is also a non-selective serotonin reuptake inhibitor and may therefore also have a mood-enhancing effect.

Mechanism of action

The drug acts on the central nervous system, where it primarily competitively blocks H ₁ receptors . The diphenhydramine acts as an inverse agonist . Like other first-generation H1 antihistamines, it is also a dirty drug that also has anticholinergic properties. In addition, 8-chlorotheophylline is used as an A receptor antagonist in order to curb the tiredness that is triggered by the H ₁ blockade (in the sense of a functional antagonist).

application areas

According to German, Austrian and Swiss approval, dimenhydrinate may be used for the prevention and symptomatic treatment of nausea and vomiting of various causes, in particular travel sickness.

Dimenhydrinate is not suitable on its own for the treatment of nausea and vomiting caused by chemotherapy .

In the United States, dimenhydrinate is freely available as a tablet, a chewable tablet, and a prescription injection.

Contraindications

For dimenhydrinate for intravenous injection (trade name Vomex A) the following absolute contraindications are listed in the technical information:

Vomex A must not be used in

Hypersensitivity / allergy to dimenhydrinate, other antihistamines or another component of the drug
acute asthma attack
Angle-closure glaucoma
Pheochromocytoma
Porphyria
Prostatic hyperplasia with residual urine
Seizures ( epilepsy , eclampsia )

The following relative contraindications (referred to as administration with particular caution ) are given:

Impaired liver function
Irregular heartbeat (arrhythmias)
Low in potassium ( hypokalaemia ), low in magnesium ( hypomagnesaemia )
Slow heart ( bradycardia )
Congenital long QT syndrome or other clinically significant heart disorders (especially coronary artery disease, conduction disorders)
Simultaneous use of drugs that also prolong the QT interval (e.g. antiarrhythmics class IA or III, antibiotics, antimalarials, antihistamines, neuroleptics) or lead to hypokalaemia
Chronic breathing difficulties and asthma
Nausea caused by a narrowed stomach outlet ( pyloric stenosis )

Side effects

Temporary numbness of the oral mucous membranes may occur while chewing dimenhydrinate preparations. Depending on the individual sensitivity and the dose taken, Dimenhydrinat u. a. cause drowsiness and drowsiness. As anticholinergic side effects dry mouth, increased to a stuffy nose, blurred vision, increased intraocular pressure and disturbances of the heartbeat sequence, sensation when urinating. Patients with congenital long QT syndrome should refrain from taking it, as the QT interval in the ECG can be dangerously prolonged by dimenhydrinate if predisposed to it.

Diphenhydramine can have a hallucinogenic and delirious effect in higher doses (of approx. 400 mg). In the drug scene it is referred to as "DMH". In this context, however, pure diphenhydramine products (without 8-chloro theophylline component) are preferred.

Trade names

Monopreparations

Antemin (CH), Emedyl (A), Reisefit Hennig (D), Reisegold (D), Reiseabletten (D), Superpep (D), Travel-Gum (A), Trawell (CH), Vertigo-Vomex (D), Vertirosan (A), Vomacur (D), Vomex A (D), RubieMen (D)

Combination preparations

Antemin compositum (CH), Arlevert (D, A), Dropa (CH), Gem Voyage (CH), Neo-Emedyl (A), Rhin-X (CH), Rotpunkt Apotheke Reiseragées (CH), Synkapton (A), Tesero (CH), Vertirosan Vitamin B ₆ (A)

Individual evidence

↑ ^a ^b ^c Datasheet Dimenhydrinate from Sigma-Aldrich , accessed on March 25, 2011 ( PDF ).
↑ ^a ^b Technical information, Astellas company, Vomex A injection solution, status 11/2008, accessed September 24, 2012.
^ Food & Drug Administration - MedlinePlus: Dimenhydrinate . Retrieved April 8, 2014.
^ Food & Drug Administration: Dimenhydrinate . Retrieved April 8, 2014.

[sigma-1] Datasheet Dimenhydrinate from Sigma-Aldrich , accessed on March 25, 2011 ( PDF ).

[fachinfo-2] Technical information, Astellas company, Vomex A injection solution, status 11/2008, accessed September 24, 2012.

[3] Food & Drug Administration - MedlinePlus: Dimenhydrinate . Retrieved April 8, 2014.

[4] Food & Drug Administration: Dimenhydrinate . Retrieved April 8, 2014.