Explanation. The quarterly trend chart illustrates changing levels of adverse events over time. Results from both the FDA Adverse Event Database (FAERS) and adverse events extracted from social media by Druginformer are plotted side-by-side for easy comparison. Common adverse drug reactions (ADRs) associated with oseltamivir therapy (occurring in over 1 percent of people) include nausea and vomiting. In adults, oseltamivir increased the risk of nausea for which the number needed to harm was 28 and for vomiting was 22. Antiviral Agents for the Treatment and Chemoprophylaxis of Influenza: Recommendations of the Advisory Committee on Immunization Practices (ACIP) Zanamivir is a medication used to treat and prevent influenza caused by influenza A and B viruses. It is a neuraminidase inhibitor and was developed by the Australian biotech firm Biota Holdings. Content on this page was developed during the 2009-2010 H1N1 pandemic and has not been updated. The H1N1 virus that caused that pandemic is now a regular human flu virus and continues to circulate seasonally worldwide. In Summary. Commonly reported side effects of oseltamivir include: nausea and vomiting. Other side effects include: abdominal pain. See below for a comprehensive list of adverse effects. Flu season can hit us pretty hard. Unfortunately, it isn’t all about runny noses and just not feeling well — the flu can be deadly. Tamiflu is an antiviral that alleviates flu symptoms as well as the duration of the flu in children age 1 and older. However, Tamiflu side effects may outweigh its benefits. Each pre-dispensed quantity of inhalation powder (one blister) contains 5 mg zanamivir. Each delivered inhalation (the amount that leaves the mouthpiece of the Diskhaler) contains 4.0 mg zanamivir. Table 2: Adverse Events* Reported Spontaneously by ≥ 1% of Subjects Within 21 Days After Administration of Afluria or Placebo, Irrespective of Causality† (Studies 1 and 2, Adult Populations) Learn about Relenza (Zanamivir) may treat, uses, dosage, side effects, drug interactions, warnings, patient labeling, reviews, and related medications.