# 3073
The surprise is that this H1N1 Swine Flu is still sensitive to Oseltamivir (Tamiflu), given that nearly 100% of the seasonal H1N1 viruses tested over the last flu season were not.
The virus is also sensitive to Zanamivir (Relenza).
How long that situation will last is anyone’s guess, but it is good news for now.
The bad news is, unlike the other H1N1 viruses in circulation, this new virus is resistant to the older Amantadines (includes Rimantadine).
Overnight the CDC released new guidelines for the use of antivirals in suspected, probable, and confirmed cases of swine flu. They also weigh in on Antiviral Chemoprophylaxis.
There is also new information on the use of antivirals on children under the age of 1 years, and pregnant women.
It is rather long, and much of it is of direct interest mostly to clinicians, so I’ll just post excerpts.
Note: I know a great many people have stockpiled Tamiflu over the past few years in anticipation of a bird flu pandemic.
Swine flu is (for now, anyway) a much less dangerous virus than H5N1.
Decisions on whether to use antivirals to treat a Swine Flu infection may not be as clear-cut as with bird flu. As with any drug, there is the possibility of adverse reactions.
Do yourself a favor and consult your physician before attempting to treat yourself or a family member.
Follow the link for the entire set of guidelines.
Interim Guidance on Antiviral Recommendations for Patients with Confirmed or Suspected Swine Influenza A (H1N1) Virus Infection and Close Contacts
April 28, 2009 05:00 AM ET
Antiviral Treatment
Confirmed, Probable and Suspected Cases
Recommendations for use of antivirals may change as data on antiviral susceptibilities become available.
Empiric antiviral treatment should be considered for confirmed, probable or suspected cases of swine influenza A (H1N1) virus infection. Treatment of hospitalized patients and patients at higher risk for influenza complications should be prioritized. Antiviral treatment with zanamivir or oseltamivir should be initiated as soon as possible after the onset of symptoms. Evidence for benefits from treatment in studies of seasonal influenza is strongest when treatment is started within 48 hours of illness onset. However, some studies of treatment of seasonal influenza have indicated benefit, including reductions in mortality or duration of hospitalization even for patients whose treatment was started more than 48 hours after illness onset. Recommended duration of treatment is five days. Recommendations for use of antivirals may change as data on antiviral susceptibilities and effectiveness become available. Antiviral doses recommended for treatment of swine influenza A (H1N1) virus infection in adults or children 1 year of age or older are the same as those recommended for seasonal influenza (Table 1). Oseltamivir use for children < 1 year old was recently approved by the U.S. Food and Drug Administration (FDA) under an Emergency Use Authorization (EUA), and dosing for these children is age-based (Table 2).
Antiviral Chemoprophylaxis
For antiviral chemoprophylaxis of swine influenza A (H1N1) virus infection, either oseltamivir or zanamivir are recommended (Table 1). Duration of antiviral chemoprophylaxis post-exposure is 10 days after the last known exposure to an ill confirmed case of swine influenza A (H1N1) virus infection. For pre-exposure protection, chemoprophylaxis should be given during the potential exposure period and continued for 10 days after the last known exposure to an ill confirmed case of swine influenza A (H1N1) virus infection. Oseltamivir can also be used for chemoprophylaxis under the EUA (Table 3).
Antiviral chemoprophylaxis (pre-exposure or post-exposure) with either oseltamivir or zanamivir is recommended for the following individuals:
- Household close contacts who are at high-risk for complications of influenza (e.g., persons with certain chronic medical conditions, persons 65 or older, children younger than 5 years old, and pregnant women) of a confirmed, probable or suspected case.
- School children who are at high-risk for complications of influenza (children with certain chronic medical conditions) who had close contact (face-to-face) with a confirmed, probable, or suspected case.
- Travelers to Mexico who are at high-risk for complications of influenza (e.g., persons with certain chronic medical conditions, persons 65 or older, children younger than 5 years old, and pregnant women).
- Health care workers or public health workers who were not using appropriate personal protective equipment during close contact with an ill confirmed, probable, or suspect case of swine influenza A (H1N1) virus infection during the case’s infectious period.
Pre-exposure antiviral chemoprophylaxis with either oseltamivir or zanamivir can be considered for the following:
- Any health care worker who is at high-risk for complications of influenza (e.g., persons with certain chronic medical conditions, persons 65 or older, children younger than 5 years old, and pregnant women) who is working in an area of the healthcare facility that contains patients with confirmed swine influenza A (H1N1) cases, or who is caring for patients with any acute febrile respiratory illness.
- Non-high risk persons who are travelers to Mexico, first responders, or border workers who are working in areas with confirmed cases of swine influenza A (H1N1) virus infection.
