Umifenovir, sold under the brand name Arbidol, is an antiviral medication for the treatment of

influenza Influenza, commonly known as "the flu", is an infectious disease caused by influenza viruses. Symptoms range from mild to severe and often include fever, runny nose, sore throat, muscle pain, headache, coughing, and fatigue. These symptoms ...

and COVID infections used in Russia and

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

. The drug is manufactured by

Pharmstandard JSC Pharmstandard (russian: ПАО "Фармстандарт", PAO "Farmstandart") is a Russian multinational pharmaceutical company. It is headquartered in Dolgoprudny, Moscow Oblast. Pharmstandard's makes and exports over 400 generic and propri ...

(russian: Фармстандарт). It is not approved by the U.S. Food and Drug Administration (FDA) for the treatment or prevention of influenza. Chemically, umifenovir features an indole core, functionalized at all but one positions with different substituents. The drug has been shown in studies to inhibit viral entry into target cells and stimulate the immune response.

Status

Testing of umifenovir's efficacy has mainly occurred in China and Russia, and it is well known in these two countries. Some of the Russian tests showed the drug to be effective and a direct comparison with oseltamivir showed similar efficiency ''in vitro'' and in a clinical setting. In 2010 Arbidol was the drug brand with the highest sales volume in Russia. In the first quarter of 2020 it had a 16 percent share in the Russian antiviral market.

Mode of action

Biochemistry

Umifenovir inhibits membrane fusion of influenza virus. Umifenovir prevents contact between the virus and target host cells. Fusion between the viral envelope (surrounding the

viral capsid A capsid is the protein shell of a virus, enclosing its genetic material. It consists of several oligomeric (repeating) structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or ma ...

) and the cell membrane of the target cell is inhibited. This prevents viral entry to the target cell, and therefore protects it from infection. Some evidence suggests that the drug's actions are more effective at preventing infections from

RNA virus An RNA virus is a virusother than a retrovirusthat has ribonucleic acid (RNA) as its genetic material. The nucleic acid is usually single-stranded RNA ( ssRNA) but it may be double-stranded (dsRNA). Notable human diseases caused by RNA viruses ...

es than infections from DNA viruses. As well as specific antiviral action against both influenza A and

influenza B ''Influenza B virus'' is the Monotypic taxon, only species in the genus ''Betainfluenzavirus'' in the virus family ''Orthomyxoviridae''. Influenza B virus is known only to infect humans and Pinniped, seals. This limited host range is apparently ...

viruses, umifenovir exhibits modulatory effects on the immune system. The drug stimulates a

humoral immune response Humoral immunity is the aspect of immunity that is mediated by macromolecules - including secreted antibodies, complement proteins, and certain antimicrobial peptides - located in extracellular fluids. Humoral immunity is named so because it in ...

, induces

interferon Interferons (IFNs, ) are a group of signaling proteins made and released by host cells in response to the presence of several viruses. In a typical scenario, a virus-infected cell will release interferons causing nearby cells to heighten the ...

-production, and stimulates the phagocytic function of

macrophage Macrophages (abbreviated as M φ, MΦ or MP) ( el, large eaters, from Greek ''μακρός'' (') = large, ''φαγεῖν'' (') = to eat) are a type of white blood cell of the immune system that engulfs and digests pathogens, such as cancer cel ...

Clinical application

A Russian packet of Arbidol capsules Umifenovir is used primarily as an antiviral treatment for influenza. The drug has also been investigated as a candidate drug for treatment of

hepatitis C Hepatitis C is an infectious disease caused by the hepatitis C virus (HCV) that primarily affects the liver; it is a type of viral hepatitis. During the initial infection people often have mild or no symptoms. Occasionally a fever, dark urine, a ...

. More recent studies indicate that umifenovir also has ''in vitro'' effectiveness at preventing entry of Zaire ebolavirus (Kikwit strain), Tacaribe arenavirus and Kaposi's sarcoma-associated herpesvirus in mammalian cell cultures, while confirming umifenovir's suppressive effect ''in vitro'' on Hepatitis B and poliovirus infection of mammalian cells when introduced either in advance of viral infection or during infection.

Side effects

Side effects in children include sensitization to the drug. No known overdose cases have been reported and allergic reactions are limited to people with hypersensitivity. The is more than 4 g/kg.

Criticism

In 2007, the Russian Academy of Medical Sciences stated that the effects of Arbidol (umifenovir) are not scientifically proven. Russian media criticized lobbying attempts by

Tatyana Golikova Tatiana Alexeyevna Golikova (Russian: Татьяна Алексеевна Голикова; born 9 February 1966) is a Russian politician and economist who serves as the Deputy Prime Minister of Russia for Social Policy, Labour, Health and Pen ...

(then-Minister of Healthcare) to promote umifenovir, and the unproven claim that Arbidol can speed up recovery from flu or cold by 1.3-2.3 days. They also made claims that the efficacy of umifenovir is supported by peer-reviewed studies.

Names

Arbidol is the INN. The brand name Arbidol is known as russian: Арбидол and .

Research

, umifenovir and darunavir were being studied as a potential combination treatment for COVID-19 in China.

References

External links

* {{Portal bar , Medicine Anti-influenza agents Anti–RNA virus drugs Indoles Bromoarenes Phenols Dimethylamino compounds Thioethers Ethyl esters Russian drugs Drugs in the Soviet Union