Neuraminidase inhibitors (NAIs) are a class of
drug
A drug is any chemical substance that causes a change in an organism's physiology or psychology when consumed. Drugs are typically distinguished from food and substances that provide nutritional support. Consumption of drugs can be via inhala ...
s which block the
neuraminidase
Exo-α-sialidase (EC 3.2.1.18, sialidase, neuraminidase; systematic name acetylneuraminyl hydrolase) is a glycoside hydrolase that cleaves the glycosidic linkages of neuraminic acids:
: Hydrolysis of α-(2→3)-, α-(2→6)-, α-(2→8)- glyc ...
enzyme. They are a commonly used
antiviral drug
Antiviral drugs are a class of medication used for treating viral infections. Most antivirals target specific viruses, while a broad-spectrum antiviral is effective against a wide range of viruses. Unlike most antibiotics, antiviral drugs do n ...
type against influenza.
Viral neuraminidase
Viral neuraminidase is a type of neuraminidase found on the surface of influenza viruses that enables the virus to be released from the host cell. Neuraminidases are enzymes that cleave sialic acid (also called neuraminic acid) groups from ...
s are essential for influenza reproduction, facilitating viral
budding
Budding or blastogenesis is a type of asexual reproduction in which a new organism develops from an outgrowth or bud due to cell division at one particular site. For example, the small bulb-like projection coming out from the yeast cell is kno ...
from the host cell.
Oseltamivir (Tamiflu),
zanamivir (Relenza),
laninamivir (Inavir), and
peramivir belong to this class. Unlike the
M2 inhibitors, which work only against the influenza A virus, NAIs act against both
influenza A and
influenza B
''Influenza B virus'' is the only species in the genus ''Betainfluenzavirus'' in the virus family ''Orthomyxoviridae''.
Influenza B virus is known only to infect humans and seals. This limited host range is apparently responsible for the lack ...
.
The NAIs oseltamivir and zanamivir were approved in the US and Europe for treatment and prevention of influenza A and B. Peramivir acts by strongly binding to the neuraminidase of the influenza viruses and inhibits activation of neuraminidase much longer than oseltamivir or zanamivir. However, laninamivir in the cells is slowly released into the respiratory tract, resulting in long-lasting anti-influenza virus activity. Thus the mechanism of the long-lasting activity of laninamivir is basically different from that of peramivir.
The efficacy was highly debated in recent years. However, after the pandemic caused by
H1N1
In virology, influenza A virus subtype H1N1 (A/H1N1) is a subtype of influenza A virus. Major outbreaks of H1N1 strains in humans include the Spanish flu, the 1977 Russian flu pandemic and the 2009 swine flu pandemic. It is an orthomyxoviru ...
in 2009, the effectiveness of early treatment with neuraminidase inhibitors in reducing serious cases and deaths was reported in various countries.
In countries where influenza-like illness is treated using NAIs on a national level, statistical reports show a low fatality record for symptomatic illness because of the universal implementation of early treatment using this class of drugs.
Although oseltamivir is widely used in these countries, there have been no outbreaks caused by oseltamivir-resistant viruses and also no serious illness caused by oseltamivir-resistant viruses has ever been reported.
The United States Centers for Disease Control and Prevention continues to recommend the use of oseltamavir treatment for people at high risk for complications and the elderly and those at lower risk who present within 48 hours of first symptoms of infection.
Common side effects include
nausea
Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of th ...
and
vomiting
Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose.
Vomiting can be the result of ailments like food poisoning, gastroenter ...
. The abnormal behaviors of children after taking oseltamivir that have been reported may be an extension of
delirium
Delirium (also known as acute confusional state) is an organically caused decline from a previous baseline of mental function that develops over a short period of time, typically hours to days. Delirium is a syndrome encompassing disturbances ...
or hallucinations caused by influenza.
It occurs in the early stages of the illness, such as within 48 hours after onset of the illness. Therefore, children with influenza are advised to be observed by their parents until 48 hours after the onset of the influenza illness, regardless of whether the child is treated with NAIs.
Specific neuraminidase inhibitors
*
Laninamivir
*
Oseltamivir (Tamiflu)
*
Peramivir (Rapivab)
*
Zanamivir (Relenza)
Structures of the viral neuraminidase inhibitors in use
Natural products
A natural product is a natural compound or substance produced by a living organism—that is, found in nature. In the broadest sense, natural products include any substance produced by life. Natural products can also be prepared by chemical sy ...
* Cyanidin-3-sambubioside (extracted from
black elderberry)
*
Coptisine
*
Berberine
Berberine is a quaternary ammonium salt from the protoberberine group of benzylisoquinoline alkaloids found in such plants as ''Berberis vulgaris'' (barberry), ''Berberis aristata'' (tree turmeric), ''Mahonia aquifolium'' (Oregon grape), ''Hydras ...
See also
*
Discovery and development of neuraminidase inhibitors
References
External links
{{DEFAULTSORT:Neuraminidase Inhibitor
Carbohydrate chemistry