Content on this page was developed during the 2009-2010 H1N1 pandemic and has not been updated.
The H1N1 virus that caused that pandemic is now a regular human flu virus and continues to circulate seasonally worldwide.
The English language content on this website is being archived for historic and reference purposes only.
For current, updated information on seasonal flu, including information about H1N1, see the CDC Seasonal Flu website.
Antiviral Safety Information
The Public Health Emergency determination for 2009 H1N1 Influenza expired on June 23, 2010,
terminating Emergency Use Authorizations issued during the pandemic, including some related to antiviral medications.
Emergency Use Authorization (EUA) for Tamiflu®: Fact Sheet for Healthcare Providers The Food and Drug Administration (FDA) has issued an EUA for the use of oseltamivir in patients younger than 1 year of age, for use in patients who are symptomatic for more than 2 days, and use in patients with complicated illness requiring hospitalization due to the 2009 H1N1 influenza virus. Please consult this Fact Sheet for general information on possible side effects of oseltamivir.
Compounding Oseltamivir Suspension – Potential Dosing Errors In the event that commercial supplies of Tamiflu® Oral Suspension are limited, oseltamivir 75 mg capsules can be compounded at most retail pharmacies. The commercially-manufactured Tamiflu® Oral Suspension concentration is 12 mg/mL; the compounded suspension concentration is 15 mg/mL.
Commercial Tamiflu® Oral Suspension – Potential Dosing Device Errors An oral dosing dispenser with 30 mg, 45 mg, and 60 mg graduations is provided with Tamiflu® Oral Suspension, rather than graduations in milliliters (mL) or teaspoons (tsp). When dispensing commercially-manufactured Tamiflu® Oral Suspension, pharmacists should ensure the units of measure on the prescription instructions match the dosing device. When dispensing Tamiflu® Oral Suspension for children younger than 1 year of age, or whose dose is less than 30 mg, the oral dosing dispenser that is included in the Tamiflu® product package should always be removed and an oral syringe that is capable of accurately measuring the prescribed dose in milliliters (mL) should be provided.
Relenza® Inhalation Powder – Warning: Powder Must Not Be Nebulized The commercial formulation of Relenza® Inhalation Powder is not designed or intended for reconstitution in any liquid formulation and is not recommended for use in any nebulizer or mechanical ventilator.
Emergency Use Authorization (EUA) for Peramivir IV: Fact Sheet for Healthcare Providers The Food and Drug Administration (FDA) has issued an EUA for the use of the unapproved (investigational) drug intravenous Peramivir for treatment of 2009 H1N1 influenza virus in certain hospitalized adult and pediatric patients. Data on the safety of Peramivir IV are limited. Please consult this Fact Sheet for general information on possible side effects of Peramivir IV. Healthcare providers who prescribe Peramivir IV are responsible for mandatory reporting to FDA MedWatch of all medication errors and selected adverse events occurring during Peramivir IV treatment within 7 calendar days from the onset of the event. The fact sheet includes information on what selected adverse events should be reported to FDA MedWatch.
FDA MedWatch Forms All medication errors and selected adverse events can be reported to FDA MedWatch online or using a PDF form. If completing a MedWatch Form for Peramivir IV, please be sure to include the Peramivir IV Request Number to which the adverse event report corresponds.
Rare Neuropsychiatric Events in Children Rarely, transient neuropsychiatric events (delirium, hallucinations, abnormal behavior) have been reported in postmarketing surveillance among persons taking oseltamivir and zanamivir. The majority of reports were among children and adolescents living in Japan. Because influenza infection itself can be associated with a variety of neurologic and behavioral symptoms, including seizures, delirium, and hallucinations, the contribution of the neuraminidase inhibitors to these neuropsychiatric effects is unclear. Until additional data are available, FDA advises that persons receiving neuraminidase inhibitors be monitored for abnormal behavior.
While oseltamivir and zanamivir are "Pregnancy Category C" medications, the available risk-benefit data indicate pregnant women with suspected or confirmed influenza should receive prompt antiviral therapy.
