The recommended antiviral drugs available for the treatment and prevention of influenza are neuraminidase inhibitors (NAIs). The aim of this study was to evaluate age-related clinical manifestations of adverse events (AEs) related to NAIs. FAERS and WebMD data were downloaded. The available NAIs selected for the analysis were oseltamivir, peramivir, zanamivir, and laninamivir. Disproportionality was analyzed using the proportional reporting ratio (PRR), the reporting odds ratio (ROR), and the information component (IC) methods. In total, 16729 AEs from 4598 patients and 575 AEs from 440 patients in the FAERS and WebMD, respectively, were included in the analysis. In the FAERS, AEs were more common among those who were younger (<19 years) for zanamivir, while for those who were older (>65 years) for peramivir. A disproportionality analysis showed that signals for vomiting and hallucinations were detected in younger patients given oseltamivir, while an abnormal hepatic function, cardiac failure, shock, and cardio-respiratory arrest were detected in older patients given peramivir. Psychiatric disorders were most common in younger and older patients, while gastrointestinal disorders were most common in adult given oseltamivir in the WebMD. Adverse symptoms related to NAIs varied and depended on the drugs used and the age of the patient.Influenza remains a major threat to public health in spite of the fact that an influenza vaccination has been shown to be effective for preventing infection. Every year worldwide, there are an estimated one billion cases of influenza, of which approximately three to five million are severe cases, resulting in 290,000 to 650,000 influenza-related deaths 1 . The recommended antiviral drugs available for the treatment and prevention of influenza are neuraminidase inhibitors (NAIs) 2 . After oseltamivir and zanamivir were approved by the U.S. Food and Drug Administration (FDA) in 1999, peramivir and laninamivir were developed for the prevention and control of influenza 3,4 , peramivir and laninamivir were developed for the prevention and control of influenza 5,6 . The two NAIs oseltamivir and zanamivir were widely used during the 2009 influenza A (H1N1) pandemic 7 . The most common adverse effects for oseltamivir are nausea, vomiting, and diarrhea 8 . Zanamivir can cause bronchospasm when administered by inhalation 4 . The U.S. FDA has recently approved the intravenous use of peramivir 5 , but has not approved laninamivir for use.Reports mostly from Japan in 2005 and 2006 suggested that oseltamivir increased the risk of neuropsychiatric symptoms such as delirium, hallucinations, and abnormal behaviors, and could lead to thoughts of self-injury or suicide in teenagers 9 . However, the U.S. FDA's pediatrics advisory committee concluded that the deaths were not related to oseltamivir, though twelve deaths were reported in Japanese children who were taking it in 2005 10 . In 2006, therefore, the U.S. FDA added a warning to the label of oseltamivir, drawing attention to the risk of developing n...