Neuraminidase inhibitors (NAIs) are antiviral medications used for the treatment and prevention of influenza A and B. They work by inhibiting the neuraminidase enzyme, preventing the release of new viral particles from infected cells and limiting viral spread. Common examples include oseltamivir (oral), zanamivir (inhaled), and peramivir (intravenous). When started early, these drugs can shorten the duration of symptoms by up to about 2.5 days.