2009 H1N1 Influenza: Resources for Pharmacists

February 5, 2010, 11:00 AM ET

This page was updated December 1, 2009 to include new information on antiviral availability and additional information that may be useful for pharmacists working in both outpatient and inpatient settings.

General Information for Pharmacists

CDC has issued recommendations for clinicians on the use of antiviral medications for the treatment and prevention of influenza for the 2009-2010 season. The Food and Drug Administration (FDA) has authorized emergency use of oseltamivir (Tamiflu®) and zanamivir (Relenza®) under certain circumstances not included in the FDA-approved uses or outside of the FDA-approved uses in response to the declaration of a public health emergency involving 2009 H1N1 influenza A virus made by the Secretary of Health and Human Services on April 26, 2009.  Additionally, FDA has recently issued an Emergency Use Authorization for the use of an unapproved (investigational) intravenous drug (peramivir) for the treatment of 2009 H1N1 influenza virus in certain hospitalized adult and pediatric patients. 

The current public health emergency has affected the nation’s pharmacists as a greater number of people than usual seek to fill prescriptions for influenza antiviral drugs or antibiotics to treat secondary infections, in addition to seeking advice on over-the-counter cough and cold medications. This may have an impact on supplies and availability of antiviral medications and other materials that may be needed to fill such prescriptions.

Antiviral Availability

At this time, CDC discussions with the antiviral supply chain (manufacturers, distributors and retailers) indicate that supplies of the Tamiflu® adult capsule formulation (75 mg) and pediatric formulations (30 mg and 45 mg capsules and Oral Suspension) and Relenza® Inhalation Powder are meeting current demand for these products. Spot shortages for these products may occur if in an area there is an unexpected increase in flu activity.

For children who are too young to use Relenza or who cannot swallow capsules, if commercial Tamiflu oral suspension product is not available, pharmacies may compound Tamiflu suspension using adult capsules. In addition, Tamiflu 30 and 45mg capsules may be mixed into a sweetened liquid by a caregiver (see detailed information below).

Pharmacies should be aware of the importance of providing patients with these influenza medications as quickly as possible when they are prescribed.  Having product at the pharmacy store level, including doses of Tamiflu® and Relenza®, and supplies to compound Tamiflu® Oral Suspension, will be critical to ensure that patients needing treatment receive it as quickly as possible.

• Limited Availability of Commercial Tamiflu® Oral Suspension
  Supplies of commercially-manufactured Tamiflu® Oral Suspension were limited in September – November 2009. In response to this, Tamiflu® Oral Suspension has been released from the CDC Strategic National Stockpile to enhance availability at state and local levels.  Some of these lots of suspension product have an expired date on the label. Under the emergency use authorization for Tamiflu® FDA has authorized the use of certain lots of expired Tamiflu®. Based on scientific review, FDA found that some Tamiflu® may be used past the expiration date printed on the package. If you want to look up the lot number for your Tamiflu to see if it has been authorized for use past its expiration date, please see the listing of antivirals at or nearing expiry.
  
  When local supplies of commercially-manufactured oral suspension are limited, physicians should consider infants and children less than one year of age or less than 33 lbs to be the highest priority for receiving the commercial suspension.
  • FDA: Information for Healthcare Professionals – Authorization of Use of Expired Tamiflu for Oral Suspension
• Supply of Ingredients Needed to Compound Tamiflu® Oral Suspension
  Tamiflu® capsules (75 mg) may be compounded using either of two vehicles: Cherry Syrup (Humco) or Ora-Sweet SF (sugar-free) (Paddock Laboratories).  As of October 28, 2009, these products may be in short supply in some locations if there is increased demand for compounding an oral suspension from Tamiflu® 75 mg capsules.  
  
  Humco reports that they have increased production of Cherry Syrup and that they are releasing new production weekly to wholesalers.  If pharmacists are having difficulty obtaining Humco Cherry Syrup, they may contact Humco directly to locate supplies at 1-800-662-3435.  Paddock Laboratories reports that they have increased production of Ora-Sweet SF and they are releasing new production daily to customers. 
  • FDA: Tamiflu Oral Suspension Shortage Information

CDC will provide additional information and updates regarding antiviral drug supplies as needed.

Antiviral Prescription and Dispensing Considerations

Oseltamivir (Tamiflu®)

• Complete information for the Emergency Use Authorization for Tamiflu® is available from CDC.  
• CDC: Emergency Use Authorization for Tamiflu®
  
• Alternatives to Tamiflu® Oral Suspension for Pediatric Patients
  While commercially-manufactured Tamiflu® Oral Suspension (12 mg/mL) is the preferred product for pediatric and adult patients who have difficulty swallowing capsules or where lower doses are needed, this product may not be locally available.
  • For patients who are less than one year old, there is one alternative:
    • a suspension compounded by a retail pharmacy (see links below)
  • For children who are at least one year old there are two alternatives:
    • a suspension compounded by a retail pharmacy (see links below)
    • 30mg, 45mg, or 75 mg capsules, which may be mixed into a sweetened liquid by a caregiver if the child cannot swallow capsules (see links below).
• Tamiflu® Oral Suspension Compounded by a Retail Pharmacy
  Compounding an oral suspension from Tamiflu® 75mg capsules as described in the FDA-approved manufacturer package insert is an alternative when commercially-manufactured oral suspension formulation is not readily available. Tamiflu® 75 mg capsules may be compounded using either of two vehicles: Cherry Syrup (Humco) or Ora-Sweet SF (sugar-free) (Paddock Laboratories). Other supplies needed include mortar and pestle and a standard pharmacy bottle, such as an amber glass or amber polyethyleneterephthalate (PET) bottle.

• FDA Drug Safety Information: Emergency Compounding of an Oral Suspension from Tamiflu® 75 mg Capsules (Final Concentration 15 mg/mL)
• FDA: Guidance to Pharmacies on Advance Compounding of Tamiflu® Oral Suspension to Provide for Multiple Prescriptions
• Institute for Safe Medication Practices Safety Alert: Tamiflu® Oral Suspension Shortage Contributing to Dosing Errors
• Opening and Mixing Tamiflu® Capsules with Liquids
  In addition, for children who may not be able to swallow capsules, Tamiflu® capsules may be opened and mixed with sweetened liquids, such as regular or sugar-free chocolate syrup, if oral suspension is not available.  Instructions for caregivers in print and video form are linked below.
  • CDC: Q&A for Caregivers: Opening and Mixing Tamiflu® Capsules with Liquids if Child Cannot Swallow Capsules
  • CDC: Caregiver Instruction Sheet: Opening and Mixing Tamiflu® Capsules with Liquids if Child Cannot Swallow Capsules
  • CDC: Opening and Mixing Tamiflu® Capsules with Liquids if Child Cannot Swallow Capsules
• Commercial Tamiflu® Oral Suspension – Potential Dosing Device Errors
  Pharmacists with access to Tamiflu® Oral Suspension should be aware that an oral dosing dispenser with 30 mg, 45 mg, and 60 mg graduations is provided in the manufacturer’s packaging, rather than graduations in milliliters (mL) or teaspoons (tsp). There have been cases where the units of measure on the prescription dosing instructions (mL, tsp) do not match the units on the dosing device (mg), which can lead to patient or caregiver confusion and dosing errors. When dispensing commercially-manufactured Tamiflu® Oral Suspension, pharmacists should ensure the units of measure on the dosing instructions match the dosing device provided. If dosing instructions specify administration using mL or tsp the device included in the Tamiflu® product package should be removed and replaced with an appropriate measuring device. When dispensing Tamiflu® Oral Suspension for children younger than 1 year of age or to children who are to receive a dose <30 mg, the oral dosing dispenser that is included in the product package should always be removed and replaced with an appropriate measuring device.

• FDA Public Health Alert: Potential Medication Errors with Tamiflu® for Oral Suspension
• Dear Healthcare Professional letter (Roche)

Zanamivir (Relenza®)

• Complete information for the Emergency Use Authorization for zanamivir is available from CDC.
  • CDC: Emergency Use Authorization for Relenza®
• 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.
• FDA Drug Safety Alert: Relenza (zanamivir) Inhalation Powder
• Dear Healthcare Professional letter (GlaxoSmithKline)

Peramivir IV

• Complete information for the Emergency Use Authorization for Peramivir IV is available from CDC.
  • CDC: Emergency Use Authorization for Peramivir IV

Note on Special Populations

Pregnant Women

Pharmacists are likely to be asked many questions from their pregnant patients about the efficacy and safety of antiviral drugs and vaccinations this flu season. Pregnant women are a particularly high-risk population for serious complications and death when infected with 2009 H1N1 influenza. Vaccination and treatment guidelines specific to pregnant women are provided below. 

• CDC: H1N1 Flu (Swine Flu): Resources for Obstetric Health Care Providers  

Pregnant women, regardless of trimester of pregnancy, should receive the inactivated seasonal influenza vaccine (trivalent inactivated vaccine) and the inactivated influenza A (H1N1) 2009 monovalent vaccine.   Pregnant women should not receive the seasonal or 2009 H1N1 monovalent live attenuated influenza vaccine (LAIV) (nasal spray)

• CDC: 2009 H1N1 Influenza Vaccine and Pregnant Women: Information for Healthcare Providers

Pregnant women or women up to 2 weeks postpartum (including following pregnancy loss) with suspected influenza should be treated with antiviral medications as early as possible in the course of their illness and at any point in their pregnancy. Treatment should not wait for laboratory confirmation of influenza.

• CDC: Updated Interim Recommendations for Obstetric Health Care Providers Related to Use of Antiviral Medications in the Treatment and Prevention of Influenza for the 2009-2010 Season

Informational Materials for Patients and Parents/Caregivers

• CDC: Q&A for Caregivers: Opening and Mixing Tamiflu Capsules with Liquids if Child Cannot Swallow Capsules
• CDC: Caregiver Instruction Sheet: Opening and Mixing Tamiflu® Capsules with Liquids if Child Cannot Swallow Capsules [PDF]
• CDC: Opening and Mixing Tamiflu Capsules with Liquids if Child Cannot Swallow Capsules
• CDC: H1N1 Flu (Swine Flu): Resources for Pregnant Women
• FDA Drug Safety Information: Tamiflu: Consumer Questions and Answers
• FDA Drug Safety Information: Relenza: Consumer Questions and Answers