Favilar200 mg

Favilar 200 mg is an antiviral medicine with regionally variable approved uses. In its original approval, it is indicated for the treatment of novel or re-emerging pandemic influenza virus infections, limited to cases in which other influenza antiviral drugs are ineffective or not sufficiently effective. In a number of countries, Favilar 200 mg has also received regional or emergency authorization for the treatment of mild to moderate COVID-19 in adults, with dosing regimens that vary by country and regulatory authority. It is effective in vitro against various influenza virus strains, including avian and swine strains.

Contains Favilar 200 mg as the active ingredient, available as oral film-coated tablets, commonly in a 200 mg strength.

Favilar 200 mg is an oral antiviral medicine that works by a different mechanism from other influenza antivirals, blocking an enzyme (RNA polymerase) that certain viruses need to replicate. It was developed and approved in Japan for pandemic influenza and has since been used, under various regional and emergency authorizations, for COVID-19 in some countries. Because SARS-CoV-2 and influenza both use a similar replication enzyme, Favilar 200 mg has been studied for COVID-19, though its approved use and recommended dosing vary by country.

Therapeutic Class: Antiviral

Favilar 200 mg is converted inside virus-infected cells to its active form, Favilar 200 mg-ribofuranosyl-5'-triphosphate, which selectively inhibits the RNA-dependent RNA polymerase of susceptible RNA viruses. This enzyme is required for viral genome replication, and its inhibition prevents the virus from multiplying.

• Taken orally, with or without food, as directed
• Swallow tablets whole with water
• Complete the full prescribed course, even if symptoms improve

The following should be assessed by a healthcare professional before combining with Favilar 200 mg:

• Pyrazinamide, which may increase blood uric acid levels when combined with Favilar 200 mg
• Repaglinide, whose blood levels may be increased by Favilar 200 mg
• Theophylline, which may increase Favilar 200 mg blood levels

Common side effects

• Diarrhoea
• Abdominal pain
• Headache
• Nausea
• Elevated blood uric acid levels
• Elevated liver enzymes (AST, ALT)

Serious side effects (seek urgent medical attention)

• Signs of liver problems: yellowing of the skin or eyes, dark urine, severe abdominal pain
• Decreased white blood cell or platelet counts
• Signs of a severe allergic reaction: rash, swelling, difficulty breathing
• Abnormal behaviour, particularly reported in influenza patients generally, such as sudden movement or wandering that could result in injury

Pregnancy

Favilar 200 mg has shown teratogenic (birth defect-causing) and embryotoxic effects in animal studies and is contraindicated in women who are known or suspected to be pregnant. A pregnancy test is generally recommended before starting treatment in women of childbearing potential, and effective contraception should be used during treatment and for a period afterward as specified in the product's labeling.

Breastfeeding

Favilar 200 mg is contraindicated during breastfeeding.

• Favilar 200 mg has shown teratogenic and embryotoxic effects in animal studies; it is contraindicated in pregnancy, and effective contraception is recommended for both female and male patients during treatment and for a period afterward (commonly around 7 days), as Favilar 200 mg has also been detected in semen.
• Monitor liver function during treatment, as elevated liver enzymes have been observed.
• Monitor blood uric acid levels, as Favilar 200 mg can raise them.
• Use with caution in patients with renal impairment, as Favilar 200 mg is primarily excreted through the kidneys; contraindicated in severe renal impairment per some labeling.
• Its use for COVID-19 is authorized only in specific countries under emergency or regional approval, and this authorization status may change; always confirm current local regulatory status and guidance before use.

Limited data are available on Favilar 200 mg overdose in humans. Suspected overdose should be evaluated promptly by a healthcare professional; treatment is generally supportive, provided in a medical facility, with monitoring of liver function and other laboratory parameters as clinically indicated.

Store at room temperature, protected from moisture and light, as directed on the product label. Keep out of reach of children.

• Renal impairment: Use with caution; contraindicated in severe renal impairment per some product labeling, given renal excretion of the drug.
• Elderly: Use with caution; specific dose adjustment recommendations should be confirmed with the treating physician.
• Hepatic impairment: Use with caution, given the risk of liver enzyme elevation associated with Favilar 200 mg.

For the approved influenza indication, treatment is given for a total of 5 days. For COVID-19, where authorized, duration varies by country guideline, ranging up to about 14 days depending on the specific regimen and clinical response. The prescribing physician determines the exact duration based on the approved regimen and the patient's condition.

Drug Class: RNA-dependent RNA polymerase (RdRp) inhibitor

Favilar 200 mg works by selectively inhibiting the RNA-dependent RNA polymerase enzyme that influenza and certain other RNA viruses, including SARS-CoV-2, need to copy their genetic material. By blocking this enzyme, Favilar 200 mg prevents the virus from replicating, helping to limit the spread of infection within the body.

Favilar 200 mg has not been well studied in the pediatric population, and its use in children is not generally established; any pediatric use should only occur under specialist guidance where clearly necessary and where an appropriate alternative is not available.