Swine flu sufferers with viruses resistant to Tamiflu may be treated with an unlicensed treatment instead, doctors have said.
A woman with severe swine flu was not responding to Tamiflu, so doctors gave her an intravenous dose of the antiviral Relenza, an article in medical journal The Lancet reports.
The 22-year-old caught the H1N1 virus after having chemotherapy for Hodgkin's disease, and her lungs subsequently filled with fluid. She needed a ventilator to help her breathe, and Tamiflu and other drugs did not help.
Relenza, or zanamivir, is usually inhaled and is not licensed to be given intravenously, but doctors got permission to administer the drug this way from the patient's family and a hospital committee. Shortly after using a dose provided by GlaxoSmithKline, the producers of zanamivir, the patient began to recover from the virus.
Michael Kidd, of University College London, leader of the study, said: "This may provide a third route to treat patients that are not responding to antiviral treatment because the active drug is not getting to the lungs.
"Although we now know our patient did not have Tamiflu-resistant virus, the intravenous zanamivir could potentially be used to treat such a case."