Faviravir200 mg

Faviravir is an antiviral medicine that inhibits viral RNA-dependent RNA polymerase (RdRp). Its approved and emergency-use indications differ by country, and its role is best understood by the strength of evidence behind each use.

• Novel/re-emerging influenza virus infections (established, approved use in country of origin): Faviravir is approved in Japan for infections caused by novel or re-emerging influenza viruses for which other antivirals are ineffective or insufficiently effective. It is not approved or intended for routine seasonal influenza and is normally reserved by national stockpile/public-health authorities for outbreak situations.
• COVID-19 (emergency/conditional-use indication): Faviravir received emergency or conditional-use authorisation in several countries, including Bangladesh, India, Russia, and others, for mild-to-moderate COVID-19 in adults. This is not an FDA- or EMA-approved indication. Evidence of meaningful clinical benefit is limited; a 2024 Cochrane systematic review found no clear benefit of Faviravir on mortality, need for mechanical ventilation, or hospitalization in COVID-19. Faviravir should be used for COVID-19 only under a physician's supervision and in line with current local treatment guidance, not as a substitute for vaccination or other established supportive care.
• Investigational/off-label use: Faviravir has been studied against other RNA viruses (e.g., certain other viral haemorrhagic fever pathogens) in research settings, but such uses remain investigational and are not established indications.

Faviravir is not approved by the US FDA or the European Medicines Agency for any indication.

Each film-coated tablet contains Favipiravir INN 200 mg.

Faviravir is a synthetic pyrazinecarboxamide-derivative antiviral drug that acts as a selective inhibitor of viral RNA-dependent RNA polymerase (RdRp). It was originally developed and approved in Japan (brand name Avigan) for novel and re-emerging influenza virus infections and has since been used, under emergency or conditional regulatory provisions in a number of countries including Bangladesh, for mild-to-moderate COVID-19.

Faviravir is supplied in Bangladesh as an oral film-coated tablet and is available only on prescription. It carries important reproductive safety warnings (teratogenicity), and its use requires careful patient selection and physician supervision.

Antiviral drug — RNA-dependent RNA polymerase (RdRp) inhibitor. Faviravir belongs to the pyrazinecarboxamide class of synthetic antivirals.

Favipiravir is a prodrug. After oral absorption it is intracellularly phosphoribosylated to its active form, Favipiravir-ribofuranosyl-5'-triphosphate (Favipiravir-RTP).

• Favipiravir-RTP is recognized by the viral RNA-dependent RNA polymerase (RdRp) as a purine nucleotide analogue (mimicking guanosine/adenosine) and is incorporated into the nascent viral RNA strand.
• This incorporation inhibits RdRp activity and causes chain termination and lethal mutagenesis of the viral genome, which selectively blocks replication of a range of RNA viruses (including influenza virus).
• Because mammalian RNA polymerases are not efficiently recognized by Favipiravir-RTP, activity against host cell replication is limited, giving the drug its viral selectivity, though this selectivity is not absolute (see Precautions).
• Favipiravir is well absorbed orally, is largely metabolized by aldehyde oxidase (with a minor contribution from xanthine oxidase), and is predominantly renally excreted as an inactive metabolite.

Take Faviravir tablets by mouth, swallowed whole with a glass of water. It may be taken with or without food, but taking it at the same times each day helps maintain even blood levels. Do not crush or chew unless advised by a physician. Complete the full prescribed course.

Faviravir has clinically significant interactions with the following:

• Pyrazinamide: Both drugs raise serum uric acid; co-administration increases the risk of hyperuricemia and gout flares. Monitor uric acid levels if used together.
• Repaglinide: Faviravir inhibits the CYP2C8 enzyme responsible for repaglinide metabolism, which can raise repaglinide plasma levels and increase the risk of hypoglycemia. Avoid co-administration where possible, or monitor blood glucose closely.
• Theophylline: May increase plasma concentrations of Faviravir; monitor for Faviravir-related adverse effects if co-administered.
• QT-prolonging drugs: Faviravir itself can prolong the QT interval; combining it with other QT-prolonging medicines (e.g., certain antiarrhythmics, some antipsychotics, some macrolide/fluoroquinolone antibiotics) increases the risk of serious arrhythmia. See Precautions and Warnings.

Always inform the prescribing physician or pharmacist of all other medicines being taken before starting Faviravir.

Adverse effects reported with Faviravir include:

• Common: hyperuricemia (raised blood uric acid), diarrhea, nausea, vomiting, decreased appetite, elevated liver transaminases (ALT/AST).
• Less common but clinically important: neutropenia, QT interval prolongation, psychiatric/behavioral disturbances (confusion, abnormal behavior), and skin rash.
• Rare: severe hepatic dysfunction, serious cardiac arrhythmia associated with QT prolongation.

Patients should seek prompt medical attention for irregular heartbeat, palpitations, yellowing of the skin/eyes, severe abdominal pain, or unusual behavioral changes while taking Faviravir.

Pregnancy: Faviravir is contraindicated in pregnancy. It has shown clear teratogenic and embryotoxic effects (including fetal death and skeletal/structural abnormalities) in every animal species tested. Faviravir must not be given to a woman who is pregnant or who may become pregnant during treatment.

• Patients who could become pregnant must use effective contraception throughout treatment with Faviravir and for at least 7 days (through completion of a full menstrual cycle, where advised by the physician) after the last dose.
• Male patients whose partner could become pregnant should use a reliable barrier method (e.g., condom) during sexual intercourse throughout treatment and for at least 7 days after the last dose of Faviravir, because Faviravir has also been detected in semen and animal data raise concern for effects mediated through male exposure.
• A pregnancy test is recommended before starting Faviravir in patients of reproductive potential where pregnancy cannot be excluded.

Lactation: Faviravir passes into breast milk. Breastfeeding is not recommended during treatment with Faviravir and for a period after the last dose as advised by the physician; discuss safe infant feeding options with a healthcare provider before starting therapy.

Faviravir requires careful clinical supervision because of the following well-documented risks:

• Reproductive toxicity: Faviravir is teratogenic; see Contraindications and Pregnancy and Lactation for mandatory contraception requirements.
• QT interval prolongation: Faviravir can prolong the QT interval. Use with caution, and obtain an ECG where feasible, in patients with congenital long QT syndrome, significant bradycardia, uncorrected electrolyte abnormalities (hypokalemia/hypomagnesemia), or concurrent use of other QT-prolonging drugs.
• Hepatotoxicity: Elevations in liver transaminases have been reported. Liver function should be monitored during treatment, particularly in patients with pre-existing hepatic impairment or prolonged treatment courses.
• Hyperuricemia: Faviravir raises serum uric acid. Use with caution in patients with gout or a history of hyperuricemia, and monitor uric acid levels, especially with concurrent pyrazinamide.
• Psychiatric/behavioral effects: Abnormal behavior has been reported; patients (and caregivers) should be monitored, particularly early in treatment.
• Antiviral stewardship: Take Faviravir exactly as prescribed by the physician; do not stop, extend, skip doses, or share this medicine with others without medical advice, as incomplete courses may reduce effectiveness and contribute to resistance.

There is limited clinical experience with Faviravir overdose. In case of a suspected overdose of Faviravir, seek immediate medical attention or contact emergency services / a poison control center. Treatment is supportive and symptomatic, with monitoring of cardiac rhythm (QT interval), liver function, and uric acid; there is no specific antidote. Do not attempt to manage a suspected overdose at home.

Store at room temperature (below 30°C), away from light and moisture. Keep out of reach of children.

• Hepatic impairment: Use Faviravir with caution in patients with hepatic impairment; monitor liver function closely. Data in severe hepatic impairment are limited, and use should be avoided unless the physician judges the benefit outweighs the risk.
• Renal impairment: Use Faviravir with caution in patients with renal impairment, as exposure to the drug and its metabolite may increase; dose adjustment recommendations are not firmly established, so use should be individualized by the treating physician, and avoided in severe renal impairment unless clearly needed.
• Elderly patients: No specific dose adjustment is established, but elderly patients should be monitored closely given higher likelihood of hepatic/renal impairment and concomitant QT-prolonging medications.
• Patients of reproductive potential: See Pregnancy and Lactation for mandatory contraception requirements.

Duration of Faviravir treatment is indication-specific: typically 5 days for approved influenza indications, and commonly 5 to 14 days for COVID-19 under emergency-use protocols, as directed by the prescribing physician. The full prescribed duration should always be completed even if symptoms resolve earlier, and should not be extended beyond what is prescribed without medical advice.

Antiviral agents; RNA-dependent RNA polymerase (RdRp) inhibitors; pyrazinecarboxamide derivatives.

Favipiravir is a prodrug that is converted intracellularly to its active triphosphate form, Favipiravir-RTP. Favipiravir-RTP is mistaken by the viral RNA-dependent RNA polymerase (RdRp) for a natural purine nucleotide and is incorporated into the growing viral RNA chain, causing chain termination and lethal mutagenesis. This selectively suppresses replication of susceptible RNA viruses, including influenza virus, while sparing host-cell RNA/DNA polymerases, which do not efficiently recognize Favipiravir-RTP.

The safety and efficacy of Faviravir in children and adolescents have not been established. Faviravir is generally not recommended for use in pediatric patients outside of investigational or specific public-health emergency protocols directed by a physician. Where used in an emergency-authorized pediatric protocol, dosing must be individualized and supervised by a specialist, and is not a matter of routine self-administration.