Seasonal Influenza (Flu)

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Antiviral Agents for Influenza

Guidance on the Use of Influenza Antiviral Agents

(Current for the 2012-2013 Influenza Season)

Current Antiviral Treatment Recommendations are available.

This page contains excerpts from Antiviral Agents for the Treatment and Chemoprophylaxis of Influenza - Recommendations of the Advisory Committee on Immunization Practices (ACIP).
PDF Version [1 MB, 28 pages]

Four licensed prescription influenza antiviral agents are available in the United States: amantadine, rimantadine, zanamivir, and oseltamivir. Zanamivir and oseltamivir are related antiviral medications in a class of medications known as neuraminidase inhibitors. These two medications are active against both influenza A and B viruses. They differ in pharmacokinetics, safety profiles, routes of administration, approved age groups, and recommended dosages (Table 1).

Amantadine and rimantadine are related antiviral drugs in a class of medications known as adamantanes. These medications are active against influenza A viruses but not influenza B viruses. In recent years, widespread adamantane resistance among influenza A (H3N2) virus strains has made this class of medications less useful clinically. In addition, circulating 2009 H1N1 virus strains are resistant to adamantanes [110]. Therefore, amantadine and rimantadine are not recommended for antiviral treatment or chemoprophylaxis of currently circulating influenza A virus strains.

Review the references cited in this guidance.

TABLE 1. Recommended dosage and schedule of influenza antiviral medications^* for treatment^† and chemoprophylaxis^§
Antiviral agent		Age group (yrs)
Antiviral agent		0--6	7--9	10--12	13--64	65 and older
Zanamivir	Treatment, influenza A and B	NA	10 mg (2 inhalations) twice daily	10 mg (2 inhalations) twice daily	10 mg (2 inhalations) twice daily	10 mg (2 inhalations) twice daily
Zanamivir	Chemoprophylaxis, influenza A and B	NA for ages 1--4	Ages 5--9 10 mg (2 inhalations) once daily	10 mg (2 inhalations) once daily	10 mg (2 inhalations) once daily	10 mg (2 inhalations) once daily
Oseltamivir^¶	Treatment,** influenza A and B	Dose varies by child's weight**	Dose varies by child's weight**	Dose varies by child's weight** More than 40 kg = adult dose	75 mg twice daily	75 mg twice daily
Oseltamivir^¶	Chemoprophylaxis, influenza A and B	Dose varies by child's weight^††	Dose varies by child's weight^††	Dose varies by child's weight^†† More than 40 kg = adult dose	75 mg once daily	75 mg once daily
Abbreviation: NA = not approved * Zanamivir is manufactured by GlaxoSmithKline (Relenza --- inhaled powder). Zanamivir is approved for treatment of persons aged 7 years and older and approved for chemoprophylaxis of persons aged 5 years and older. Zanamivir is administered through oral inhalation by using a plastic device included in the medication package. Patients will benefit from instruction and demonstration of the correct use of the device. Zanamivir is not recommended for those persons with underlying airway disease. Oseltamivir is manufactured by Roche Pharmaceuticals (Tamiflu --- tablet). Oseltamivir is approved for treatment of persons aged 2 weeks and older and for chemoprophylaxis of persons aged 1 year and older. Oseltamivir is available for oral administration in 30 mg, 45 mg, and 75 mg capsules and liquid suspension. This information is based on data published by the Food and Drug Administration (FDA). † Recommended duration for antiviral treatment is 5 days. Longer treatment courses can be considered for patients who remain severely ill after 5 days of treatment. § Recommended duration of post-exposure chemoprophylaxis for high-risk patients is 7 days after the most recent known exposure if chemoprophylaxis can be started within 48 hours of exposure; however, early treatment if symptomatic is preferred. For control of outbreaks in long-term care facilities and hospitals, CDC recommends antiviral chemoprophylaxis for a minimum of 2 weeks and up to 1 week after the most recent known case was identified ¶ See Table 4 for information about use of oseltamivir for infants aged younger than 1 year. A reduction in the dose of oseltamivir is recommended for persons with creatinine clearance less than 30 mL/min. ** The treatment dosing recommendation for oseltamivir for children aged 2 weeks to younger than one year is 3mg/kg twice a day. The treatment dosing recommendation for oseltamivir for children aged 1 year and older who weigh 15 kg or less is 30 mg twice a day. For children who weigh more than 15 kg and up to 23 kg, the dose is 45 mg twice a day. For children who weigh more than 23 kg and up to 40 kg, the dose is 60 mg twice a day. For children who weigh more than 40 kg, the dose is 75 mg twice a day. †† The chemoprophylaxis dosing recommendation for oseltamivir for children aged 1 year and older who weigh 15 kg or less is 30 mg once a day. For children who weigh more than 15 kg and up to 23 kg, the dose is 45 mg once a day. For children who weigh more than 23 kg and up to 40 kg, the dose is 60 mg once a day. For children who weigh more than 40 kg, the dose is 75 mg once a day.

TABLE 4. Dosing recommendations for treatment or chemoprophylaxis of children aged younger than 1 year using oseltamivir*
Age	Recommended treatment dose for 5 days†	Recommended chemoprophylaxis†
Younger than 3 mos	3 mg/kg/dose twice daily	Not recommended unless situation judged critical because of limited data on use in this age group
3--11 mos	3 mg/kg/dose twice daily	3 mg/kg/dose once daily
* An Emergency Use Authorization (EUA) was issued by the FDA on April 28, 2009, and expired on June 23, 2010. This EUA allowed use of oseltamivir for treatment or chemoprophylaxis of 2009 pandemic influenza A (H1N1) virus infection during the pandemic in infants aged younger than 1 year. Currently circulating 2009 H1N1, seasonal influenza A (H3N2), and B viruses are susceptible to oseltamivir. † Current weight-based dosing recommendations are not appropriate for premature infants. Premature infants might have slower clearance of oseltamivir because of immature renal function, and doses recommended for full-term infants might lead to very high drug concentrations in this age group. Very limited data from a small cohort of premature infants suggested that oseltamivir concentrations among premature infants administered oseltamivir 1 mg/kg twice daily would be similar to those observed with the recommended treatment dose in term infants (3 mg/kg twice daily). Observed drug concentrations were highly variable among premature infants. These data are insufficient to recommend a specific dose of oseltamivir for premature infants [202].