Zanamivir, sold under the brand name Relenza among others, is an anti-viral medication used to treat and prevent influenza caused by influenza A and influenza B viruses. It is a neuraminidase inhibitor and was developed by the Australian biotech firm Biota Holdings. It was licensed to Glaxo Wellcome in 1990 and approved in the US in 1999, only for use as a treatment for influenza. In 2006, it was approved for prevention of influenza A and B. Zanamivir is the first neuraminidase inhibitor commercially developed. It was developed by GlaxoSmithKline.