In the UK, the HPA has recorded eight cases of oseltamivir-resistant H1N1pdm09 in the community setting.

BBC: Drug-resistant pandemic swine flu 'community risk'

Routine sampling in the UK has shown that there is currently no resistance to oseltamivir or zanamivir.

BBC: Tamiflu

Oseltamivir (Tamiflu) or zanamivir (Relenza) should be administered as soon as possible to patients with a suspected or confirmed H7N9 infection, the two wrote.

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The new strain of swine flu has been resistant to the antiviral drugs amantadine and rimantadine, but has responded to the other licensed options: oseltamivir and zanamivir.

CNN: CDC confirms 7 cases of swine flu in humans

But Tamiflu (oseltamivir) is now powerless against the strain that has been found in people in the community rather than sick patients with serious underlying conditions and weak immune systems.

BBC: Drug-resistant pandemic swine flu 'community risk'

There have been sporadic instances of resistance to oseltamivir -- the generic name for Tamiflu, one of the main drugs used against influenza -- but such cases are still "isolated and infrequent, " he said.

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To date, the CDC has not found any incidence of Influenza A or B resistance to the two main anti-viral medications given to patients within the first 48 hours of infection: oseltamivir and zanamivir.

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The antiviral medications Tamiflu (oseltamivir) and Relenza (zanamivir) can reduce the severity of symptoms and the length of illness, but the drug has to be taken within 48 hours of the first appearance of symptoms -- you know, the "I will not get sick" phase -- to be most effective.

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