Quifenadine ( rus, хифенадин, trade name: Phencarol, Фенкарол) is a 2nd generation

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 provid ...

drug, marketed mainly in

post-Soviet countries The post-Soviet states, also known as the former Soviet Union (FSU), the former Soviet Republics and in Russia as the near abroad (russian: links=no, ближнее зарубежье, blizhneye zarubezhye), are the 15 sovereign states that wer ...

. Chemically, it is a

quinuclidine Quinuclidine is an organic compound and a bicyclic amine and used as a catalyst and a chemical building block. It is a strong base with p''K''a of the conjugate acid of 11.0.{{cite journal , title=Azatriquinanes: Synthesis, Structure, and Reacti ...

derivative In mathematics, the derivative of a function of a real variable measures the sensitivity to change of the function value (output value) with respect to a change in its argument (input value). Derivatives are a fundamental tool of calculus. ...

. The drug has

antiarrhythmic Antiarrhythmic agents, also known as cardiac dysrhythmia medications, are a group of pharmaceuticals that are used to suppress abnormally fast rhythms (Tachycardia, tachycardias), such as atrial fibrillation, supraventricular tachycardia and vent ...

properties, probably due to the presence of a quinuclidine nucleus in the molecule's core. It acts as a calcium channel blocker and influences the activity of potassium channels. In children with cardiac arrhythmia, combination therapy with quifenadone and either

amiodarone Amiodarone is an antiarrhythmic medication used to treat and prevent a number of types of cardiac dysrhythmias. This includes ventricular tachycardia (VT), ventricular fibrillation (VF), and wide complex tachycardia, as well as atrial fibril ...

propafenone Propafenone, sold under the brand name Rythmol among others, is a class 1c anti-arrhythmic medication, which is used to treat illnesses associated with rapid heart beat such as atrial and ventricular arrhythmias. Mechanism of action Propafen ...

was found to be more effective than monotherapy with either amiodarone or propafenone. Quifenadine is a derivative of quinuclidylcarbinol, which reduces the effects of histamine on organs and systems. Quifenadine is a competitive blocker of H1 receptors. In addition, it activates the diamine oxidase enzyme, which breaks down about 30% of endogenous histamine. This explains the effectiveness of quifenadine in patients insensitive to other antihistamines. The antihistaminic qualities of quifenadine are associated with the presence of a cyclic quinuclidine core in the structure and the distance between the diphenylcarbinol group and the nitrogen atom. In terms of antihistaminic activity and duration of action, quifenadine is superior to diphenhydramine. Quifenadine reduces the toxic effect of histamine, eliminates or weakens its bronchoconstrictor effect and spasmodic effect on the smooth muscles of the intestines, has a moderate antiserotonin and weak cholinolytic effect, has well-defined antipruritic and desensitizing properties. Quifenadine weakens the hypotensive effect of histamine and its effect on capillary permeability, does not directly affect cardiac activity and blood pressure, does not have a protective effect in aconitine arrhythmias.

Indications

Allergic rhinitis 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 ...

* Acute and chronic

urticaria Hives, also known as urticaria, is a kind of skin rash with red, raised, itchy bumps. Hives may burn or sting. The patches of rash may appear on different body parts, with variable duration from minutes to days, and does not leave any long-last ...

Angioedema Angioedema is an area of swelling (edema) of the lower layer of skin and tissue just under the skin or mucous membranes. The swelling may occur in the face, tongue, larynx, abdomen, or arms and legs. Often it is associated with hives, which are ...

Dermatitis Dermatitis is inflammation of the skin, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened. The area of skin involved can ...

* Atopic dermatitis *

Pruritus Itch (also known as pruritus) is a sensation that causes the desire or reflex to scratch. Itch has resisted many attempts to be classified as any one type of sensory experience. Itch has many similarities to pain, and while both are unpleasant ...

Synthesis

Same precursor as for

mequitazine Mequitazine (trade name Primalan) is an H1 antagonist and anticholinergic of the phenothiazine chemical class. It is used to treat allergies and rhinitis. It was patented in 1969 and came into medical use in 1976. Contraindications Severe l ...

. Use patent:Mikhail Davydovich Mashkovsky, et al. (1978). Quifenadine synthesis

The

Grignard reaction The Grignard reaction () is an organometallic chemical reaction in which alkyl, allyl, vinyl, or aryl-magnesium halides (Grignard reagent) is added to a carbonyl group in an aldehyde or ketone. This reaction is important for the formation of ...

between methylquinuclidine-3-carboxylate 8206-86-9(1) and phenylmagnesium bromide (2) gave the benzhydryl alcohol product ~29% yield. The ethyl ester is cas: 238-33-1

References

Quinuclidines Antihistamines Tertiary alcohols Russian drugs Antiarrhythmic agents Drugs in the Soviet Union {{respiratory-system-drug-stub