Detailed drug Information for Tamiflu. Includes common brand names, drug descriptions, warnings, side effects and dosing information. Tamiflu is a prescription medication used to treat influenza, or flu, virus. It can shorten the duration of the flu if taken as soon as symptoms start. Tamiflu (oscltamivir phosphate) is an antiviral medication used to treat flu symptoms caused by influenza virus in patients who have had symptoms for less than 2 days. Tamiflu (oseltamivir) is an antiviral medication that blocks the actions of influenza virus types A and B in your body. Tamiflu is used to treat flu symptoms caused by influenza virus in people have had symptoms for less than 2 days. Find information about common, infrequent and rare side effects of Tamiflu Oral. 2 11 Signs It's More Serious Than the Common Cold Doctors explain how to tell if you have the common cold or something more. What should I discuss with my healthcare provider before using oseltamivir (Tamiflu)? You should not use oseltamivir if you are allergic to it. Q. What is Tamiflu and what is it approved for? A. Tamiflu (oseltamivir phosphate) is an antiviral drug. It works by attacking the flu virus to keep it from multiplying in your body and by. Learn more from WebMD about flu treatment with antiviral drugs, which shorten the duration of the virus and may ease the severity of symptoms. FREE SHIPPING on all orders! Buy prescription Tamiflu without prescription! The above Tamiflu information is intended to supplement, not substitute for, the expertise and judgment of your physician, or other healthcare professional.