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Information |
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Drug Groups
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approved |
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Description
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Dimetindene (Fenistil) is an antihistamine/anticholinergic used orally and locally as an antipruritic. |
| Indication |
Indicated as symptomatic treatment of allergic reactions: urticaria, allergies of the upper respiratory tract such as hey fever and perennial rhinitis, food and drug allergies; pruritus of various origins, except pruritus due to cholestasis; insect bites. Dimethindene is also indicated for pruritus in eruptive skin diseases such as chicken-pox. Dimethindene can also be used as an adjuvant in eczema and other pruriginous dermatoses of allergic origin. |
| Pharmacology |
Dimethindene occurs as a racemic mixture. The (S)-(+)-dimethindene is a potent M2-selective muscarinic receptor antagonist (with lower affinity for M1, M3, and M4 muscarinic receptors). The (R)-(-)-enantiomer is the eutomer (responsible for bioactivity) for histamine H1 receptor binding. |
| Toxicity |
As with other antihistaminic drugs, overdosage can produce the following symptoms: CNS depression accompanied by drowsiness (especially in adults), CNS stimulation and antimuscarinic effects (especially in children) including the following: excitation, ataxia, hallucinations, tonic or clonic spasms, mydriasis, dryness of the mouth, redness of the face, urine retention, fever and tachycardia. Blood hypotension is also possible. In its terminal phase, coma can be aggravated by cardiorespiratory colapse and death. There has been no report of a fatal outcome of Dimethindene overdosage. |
| Affected Organisms |
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Humans and other mammals |
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| References |
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Lambrecht G, Gross J, Mutschler E: Neuronal soma-dendritic and prejunctional M1-M4 receptors in gastrointestinal and genitourinary smooth muscle. Life Sci. 1999;64(6-7):403-10.
[Pubmed]
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[Novartis Pamphlet]
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