Dimetindene , also sold under the brand name Fenistil, is an

antihistamine Antihistamines are drugs which treat allergic rhinitis, common cold, influenza, and other allergies. Typically, people take antihistamines as an inexpensive, generic (not patented) drug that can be bought without a prescription and provides re ...

anticholinergic Anticholinergics (anticholinergic agents) are substances that block the action of the neurotransmitter called acetylcholine (ACh) at synapses in the central and peripheral nervous system. These agents inhibit the parasympathetic nervous system ...

. It is a first generation selective

H1 antagonist H1 antagonists, also called H1 blockers, are a class of medications that block the action of histamine at the H1 receptor, helping to relieve allergic reactions. Agents where the main therapeutic effect is mediated by negative modulation of h ...

. Dimetindene is an atypical first generation H1 antagonist as it only minimally passes across the

blood–brain barrier The blood–brain barrier (BBB) is a highly selective semipermeable membrane, semipermeable border of endothelium, endothelial cells that prevents solutes in the circulating blood from ''non-selectively'' crossing into the extracellular fluid of ...

. Dimetindene is also an

M2 receptor The muscarinic acetylcholine receptor M2, also known as the cholinergic receptor, muscarinic 2, is a muscarinic acetylcholine receptor that in humans is encoded by the ''CHRM2'' gene. Multiple alternatively spliced transcript variants have been ...

antagonist. It was patented in 1958 and came into medical use in 1960.

Medical use

Dimetindene is used orally and topically as an

antipruritic Antipruritics, abirritants, or anti-itch drugs, are medications that inhibit the itching (Latin: ''pruritus'') often associated with sunburns, allergic reactions, eczema, psoriasis, chickenpox, fungal infections, insect bites and stings like those ...

. It is used topically to treat skin irritations, such as insect bites. Dimetindene is also administered orally to treat allergies, such as

hay fever Allergic rhinitis, of which the seasonal type is called hay fever, is a type of inflammation in the nose that occurs when the immune system overreacts to allergens in the air. Signs and symptoms include a runny or stuffy nose, sneezing, red, i ...

. It is commonly formulated as its

maleic acid Maleic acid or ''cis''-butenedioic acid is an organic compound that is a dicarboxylic acid, a molecule with two carboxyl groups. Its chemical formula is HO2CCH=CHCO2H. Maleic acid is the ''cis''-isomer of butenedioic acid, whereas fumaric acid ...

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantitie ...

, dimethindene maleate.

Names

It is sold under the brand name

Fenistil Fenistil is a brand name for some over the counter medications distributed by GlaxoSmithKline and Novartis. Products include: * Fenistil Gel, containing dimetindene * Fenistil Cold Sore Cream, containing penciclovir * FeniHydrocort, containing cort ...

among others.

References

{{Muscarinic acetylcholine receptor modulators H1 receptor antagonists Indenes Muscarinic antagonists 2-Pyridyl compounds