Dimetinden

Structural formula
Simplified structural formula without stereochemistry
General
Non-proprietary name	Dimetinden
other names	( RS ) - N , N -dimethyl-3- [1- (2-pyridyl) -ethyl] -1 H -inden-2-ethanamine Latin : Dimetindenum
Molecular formula	C 20 H 24 N 2
Brief description	oily liquid
External identifiers / databases
CAS number 5636-83-9 3614-69-5 [ dimetindene maleate (1: 1)] EC number 227-083-8 ECHA InfoCard 100.024.622 PubChem 21855 ChemSpider 20541 DrugBank DB08801 Wikidata Q426070
Drug information
ATC code	D04 AA13 R06 AB03
Drug class	Antihistamines
properties
Molar mass	292.42 g · mol -1
boiling point	165-175 ° C (67 Pa )
solubility	very sparingly soluble in water: 239 mg l −1 (37 ° C)
safety instructions
Please note the exemption from the labeling requirement for drugs, medical devices, cosmetics, food and animal feed GHS labeling of hazardous substances Maleate Caution H and P phrases H: 302 P: 264-270-301 + 312-330-501
Toxicological data	618 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 .

Dimetinden is a drug from the group of H ₁ antihistamines of the first generation with pronounced anticholinergic effects, which is used, mostly as dimetindene maleate , in the treatment of allergic diseases .

Clinical information

Application areas (indications)

The active ingredient is used for the symptomatic treatment of allergic diseases . The range of indications also includes allergic reactions, itching with skin diseases and insect bites, complaints with food allergies and allergies before medical examinations or before anesthesia. In the treatment of anaphylaxis and anaphylactic shock , Dimetinden iv can be used in accordance with guidelines .

Drug interactions

Concomitant use of tricyclic antidepressants and dimetindene maleate can lead to an attack in patients with a tendency to develop glaucoma . The effect of alcohol and centrally active drugs can be increased by dimetindene maleate.

Use during pregnancy and breastfeeding

1st trimester:  Long market experience has not confirmed the earlier suspicion of teratogenic effects in humans for any of the sedating antihistamines.

2-3 Trimester / Perinatal:  With some older antihistamines (e.g. diphenhydramine and hydroxyzine), adjustment disorders such as tremor and diarrhea have been described in individual cases after long-term therapy up to birth.

Clinical features:  With long-term therapy, symptoms such as restlessness or slight sedation in the infant cannot be ruled out with all antihistamines. No data on excretion in breast milk are available for dimetinden. 

Recommendation:  Dimetinden can be taken during breastfeeding if the infant is closely observed. If symptoms occur in the breastfed infant, the preparation should be changed. Primarily non-sedating antihistamines such as loratadine or cetirizine are possible.

Pharmacological properties

Mechanism of action (pharmacodynamics)

Dimetindene is an antihistamine of the type of the H ₁ receptor - antagonist and inhibits in vitro and in vivo by H ₁ receptors of histamine-mediated effects. In addition, as a muscarinic receptor antagonist, Dimetinden is a potent anticholinergic , which makes it possible to use it off-label (especially in neurology ).

Side effects and toxicology

Unwanted anticholinergic effects and poisoning by dimetindene maleate are expressed primarily through central nervous symptoms. These range from drowsiness, ataxia, and tremors to tonic-clonic seizures. In addition, shortness of breath, increased saliva secretion and mydriasis can occur. On the acute toxicity of dimetindene, data are available for rats, mice, guinea pigs and dogs:

Acute toxicity of dimetindene maleate:

species	LD50 (mg / kg body weight)
Rat po	618.24 ± 72.3
Rat iv	26.8 ± 2.1
Mouse po	760 (670-940)
Guinea pig po	888.0 ± 92
Dog iv	40

Stereochemistry

( S ) -enantiomer (top) and ( R ) -enantiomer (bottom) of dimetindene

Dimetinden is a chiral drug with a stereocenter . The racemate , the 1: 1 mixture of the ( S ) and ( R ) isomers, is used therapeutically , mostly as the salt of maleic acid ( dimetindene maleate ).

Trade names

Monopreparations

Fenistil (D, A, CH, I), Feniallerg (CH), Histakut (D, A)

Combination preparations

Vibrocil (A, CH)

Individual evidence

1. ↑ ^{a b c} Entry on Dimetinden. In: Römpp Online . Georg Thieme Verlag, accessed on November 11, 2014.
2. ↑ Entry on Dimetinden in the ChemIDplus database of the United States National Library of Medicine (NLM) .
3. ↑ ^{a b} LGC Standards: Dimetindene Maleate , accessed December 27, 2019.
4. ↑ AWMF: Guideline on acute therapy and management of anaphylaxis . In: Allergo J Int. 23, 2014, p. 96.
5. ↑ Embryotox - drug safety in pregnancy and lactation: Database drugs and active ingredients: Dimetinden. In: www.embryotox.de. Retrieved June 9, 2016 . 
6. ^ O. Pfaff, C. Hildebrandt, M. Waelbroeck, X. Hou, U. Moser, E. Mutschler, G. Lambrecht: The (S) - (+) - enantiomer of dimethindene: a novel M2-selective muscarinic receptor antagonist . In: European journal of pharmacology. Volume 286, Number 3, November 1995, pp. 229-240, PMID 8608784 .
7. ↑ TM Böhme, C. Keim, K. Kreutzmann, M. Linder, T. Dingermann, G. Dannhardt, E. Mutschler, G. Lambrecht: Structure-activity relationships of dimethindene derivatives as new M2-selective muscarinic receptor antagonists. In: Journal of medicinal chemistry. Volume 46, Number 5, February 2003, pp. 856-867, doi : 10.1021 / jm020895l , PMID 12593665 .
8. ↑ External identifiers of or database links to dimetinden maleate : CAS number: 3614-69-5, EC number: 222-789-2, ECHA InfoCard: 100.020.718 , PubChem : 5282414 , ChemSpider : 4445569 , Wikidata : Q27265113 .

This article is about a health issue. It is not used for self-diagnosis and does not replace a diagnosis by a doctor. Please note the information on health issues !