what are the active ingredients in favipiravir medicine
Answers
Answer:
Favipiravir, sold under the brand name Avigan, is an antiviral medication used to treat influenza in Japan.[1] It is also being studied to treat a number of other viral infections.[1] Like the experimental antiviral drugs (T-1105 and T-1106), it is a pyrazinecarboxamide derivative.
It is being developed and manufactured by Toyama Chemical (Fujifilm group) and was approved for medical use in Japan in 2014.[2] In 2016, Fujifilm licensend API for it to Zhejiang Hisun Pharmaceutical Co. of China.[3] It became a generic drug in 2019.Medical use
Favipiravir has been approved to treat influenza in Japan.[2] It is, however, only indicated for novel influenza (strains that cause more severe disease) rather than seasonal influenza.[2] As of 2020, the probability of resistance developing appears low.[2]
Side effects
There is evidence that use during pregnancy may result in harm to the baby.[2]
Mechanism of action
The mechanism of its actions is thought to be related to the selective inhibition of viral RNA-dependent RNA polymerase.[4] Other research suggests that favipiravir induces lethal RNA transversion mutations, producing a nonviable viral phenotype.[5] Favipiravir is a prodrug that is metabolized to its active form, favipiravir-ribofuranosyl-5'-triphosphate (favipiravir-RTP), available in both oral and intravenous formulations.[6][7] Human hypoxanthine guanine phosphoribosyltransferase (HGPRT) is believed to play a key role in this activation process.[8] Favipiravir does not inhibit RNA or DNA synthesis in mammalian cells and is not toxic to them.[9] In 2014, favipiravir was approved in Japan for stockpiling against influenza pandemics.[10] However, favipiravir has not been shown to be effective in primary human airway cells, casting doubt on its efficacy in influenza treatment.[11]
Approval status
The US Department of Defense developed favipiravir in partnership with MediVector, Inc. as a broad-spectrum antiviral and sponsored it through FDA Phase II and Phase III clinical trials, where it demonstrated safety in humans and efficacy against the influenza virus.[12] Despite demonstrating safety in more than 2,000 patients and showing accelerated clearance of influenza virus by 6 to 14 hours in the Phase III trials, favipiravir remains unapproved in the UK and the USA.[13] In 2014, Japan approved favipiravir for treating influenza strains unresponsive to current antivirals.[14] Toyama Chemical initially hoped that favipiravir would become a new influenza medication that could replace oseltamivir (brand name Tamiflu). However, animal experiments show the potential for teratogenic effects, and the approval of production by The Ministry of Health, Labor and Welfare was greatly delayed and the production condition is limited only in an emergency in Japan.[15]
On 15 March 2020, the drug was approved in China for the treatment of influenza.[16]
Research
COVID-19
See also: Coronavirus disease 2019 § Research, and COVID-19 drug repurposing research
In February 2020, favipiravir was being studied in China for experimental treatment of the emergent COVID-19.[17][18] Trials are also being planned in Japan.[19]
A study on 80 people in comparison to lopinavir/ritonavir found that it reduced viral clearance time, and that 91% of people had improved CT scans with few side effects. The limitation of this study was that it was not randomized double-blinded and placebo-controlled.[20][21]
The drug has been approved for use in clinical trials of coronavirus disease 2019 in China.[16] In March 2020, Italy approved the drug for experimental use against COVID-19 and has begun conducting trials in three regions most affected by the disease.[22] The Italian Pharmaceutical Agency, however, has reminded the public that the existing evidence in support of this drug is scant and preliminary.[23] There are plans to study it in three hospitals in Massachusetts, USA as of April 20, 2020.[24] As of early May 2020, a trial is starting in London, UK [25]
Other
In experiments in animals favipiravir has shown activity against West Nile virus, yellow fever virus, foot-and-mouth disease virus as well as other flaviviruses, arenaviruses, bunyaviruses and alphaviruses.[9] Activity against enteroviruses[34] and Rift Valley fever virus has also been demonstrated.[35] Favipiravir has showed limited efficacy against Zika virus in animal studies, but was less effective than other antivirals such as MK-608.[36] The agent has also shown some efficacy against rabies,[37] and has been used experimentally in some humans infected with the virus.[38]
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