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. Antiviral drugs are a class of antimicrobials, a larger group which also includes antibiotic, antifungal and antiparasitic drugs, or antiviral drugs based on monoclonal antibodies. Most antivirals are considered relatively harmless to the host, and therefore can be used to treat infections. They should be distinguished from virucides, which are not medication but deactivate or destroy virus particles, either inside or outside the body. Natural virucides are produced by some plants such as eucalyptus and Australian tea trees.
The rhinovirus is a positive-sense, single-stranded RNA virus belonging to the genus Enterovirus in the family Picornaviridae. Rhinovirus is the most common viral infectious agent in humans and is the predominant cause of the common cold.
Defective interfering particles (DIPs), also known as defective interfering viruses, are spontaneously generated virus mutants in which a critical portion of the particle's genome has been lost due to defective replication or non-homologous recombination. The mechanism of their formation is presumed to be as a result of template-switching during replication of the viral genome, although non-replicative mechanisms involving direct ligation of genomic RNA fragments have also been proposed. DIPs are derived from and associated with their parent virus, and particles are classed as DIPs if they are rendered non-infectious due to at least one essential gene of the virus being lost or severely damaged as a result of the defection. A DIP can usually still penetrate host cells, but requires another fully functional virus particle to co-infect a cell with it, in order to provide the lost factors.
Zanamivir is a medication used to treat and prevent influenza caused by influenza A and influenza B viruses. It is a neuraminidase inhibitor and was developed by the Australian biotech firm Biota Holdings. It was licensed to Glaxo in 1990 and approved in the US in 1999, only for use as a treatment for influenza. In 2006, it was approved for prevention of influenza A and B. Zanamivir was the first neuraminidase inhibitor commercially developed. It is marketed by GlaxoSmithKline under the trade name Relenza as a powder for oral inhalation.
Oseltamivir, sold under the brand name Tamiflu among others, is an antiviral medication used to treat and prevent influenza A and influenza B, viruses that cause the flu. Many medical organizations recommend it in people who have complications or are at high risk of complications within 48 hours of first symptoms of infection. They recommend it to prevent infection in those at high risk, but not the general population. The Centers for Disease Control and Prevention (CDC) recommends that clinicians use their discretion to treat those at lower risk who present within 48 hours of first symptoms of infection. It is taken by mouth, either as a pill or liquid.
Neuraminidase inhibitors (NAIs) are a class of drugs which block the neuraminidase enzyme. They are a commonly used antiviral drug type against influenza. Viral neuraminidases are essential for influenza reproduction, facilitating viral budding 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.
Peramivir is an antiviral drug developed by BioCryst Pharmaceuticals for the treatment of influenza. Peramivir is a neuraminidase inhibitor, acting as a transition-state analogue inhibitor of influenza neuraminidase and thereby preventing new viruses from emerging from infected cells. It is approved for intravenous administration.
Treatments for influenza include a range of medications and therapies that are used in response to disease influenza. Treatments may either directly target the influenza virus itself; or instead they may just offer relief to symptoms of the disease, while the body's own immune system works to recover from infection.
Umifenovir, sold under the brand name Arbidol, is sold and used as an antiviral medication for influenza in Russia and China. The drug is manufactured by Pharmstandard. It is not approved by the U.S. Food and Drug Administration (FDA) for the treatment or prevention of influenza.
Buformin (1-butylbiguanide) is an oral antidiabetic drug of the biguanide class, chemically related to metformin and phenformin. Buformin was marketed by German pharmaceutical company Grünenthal as Silubin.
Nitazoxanide, sold under the brand name Alinia among others, is a broad-spectrum antiparasitic and broad-spectrum antiviral medication that is used in medicine for the treatment of various helminthic, protozoal, and viral infections. It is indicated for the treatment of infection by Cryptosporidium parvum and Giardia lamblia in immunocompetent individuals and has been repurposed for the treatment of influenza. Nitazoxanide has also been shown to have in vitro antiparasitic activity and clinical treatment efficacy for infections caused by other protozoa and helminths; evidence as of 2014 suggested that it possesses efficacy in treating a number of viral infections as well.
Z-DNA-binding protein 1, also known as DNA-dependent activator of IFN-regulatory factors (DAI) and DLM-1, is a protein that in humans is encoded by the ZBP1 gene.
Geranium macrorrhizum is a species of hardy flowering herbaceous perennial plant in the genus Geranium, family Geraniaceae. It is native to the South east Alps and the Balkans. Its common names include bigroot geranium, Bulgarian geranium, and rock crane's-bill.
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 begin one to four days after exposure to the virus and last for about two to eight days. Diarrhea and vomiting can occur, particularly in children. Influenza may progress to pneumonia from the virus or a subsequent bacterial infection. Other complications include acute respiratory distress syndrome, meningitis, encephalitis, and worsening of pre-existing health problems such as asthma and cardiovascular disease.
An antiviral stockpile is a reserve supply of essential antiviral medications in case of shortage. Many countries have chosen to stockpile antiviral medications against pandemic influenza. Because of the time required to prepare and distribute an influenza vaccine, these stockpiles are the only medical defense against widespread infection for the first six months. The stockpiles may be in the form of capsules or simply as the active pharmaceutical ingredient, which is stored in sealed drums and, when needed, dissolved in water to make a bitter-tasting, clear liquid.
Laninamivir (CS-8958) is a neuraminidase inhibitor that is a drug used for the treatment and prophylaxis of Influenzavirus A and Influenzavirus B. It is currently in Phase III clinical trials. It is a long-acting neuraminidase inhibitor administered by nasal inhalation.
Antiviral proteins are proteins that are induced by human or animal cells to interfere with viral replication. These proteins are isolated to inhibit the virus from replicating in a host's cells and stop it from spreading to other cells. The Pokeweed antiviral protein and the Zinc-Finger antiviral protein are two major antiviral proteins that have undergone several tests for viruses, including HIV and influenza.
Influenza A virus subtype H7N9 (A/H7N9) is a subtype of the influenza A virus, which causes influenza (flu), predominantly in birds. It is enzootic in many bird populations. The virus can spread rapidly through poultry flocks and among wild birds; it can also infect humans that have been exposed to infected birds.
Favipiravir, sold under the brand name Avigan among others, is an antiviral medication used to treat influenza in Japan. It is also being studied to treat a number of other viral infections, including SARS-CoV-2. Like the experimental antiviral drugs T-1105 and T-1106, it is a pyrazinecarboxamide derivative.
Riamilovir, sold under the brand name Triazavirin, is a broad-spectrum antiviral drug developed in Russia through a joint effort of Ural Federal University, Russian Academy of Sciences, Ural Center for Biopharma Technologies and Medsintez Pharmaceutical. It has a novel triazolotriazine core, which represents a new structural class of non-nucleoside antiviral drugs.
