To work well, you must take these medicines within 48 hours after the flu begins. They reduce the length or time fever and other symptoms last and allow you to return to your daily routine quicker. You can have flu complications if you get a bacterial infection, which causes pneumonia in your weakened lungs. Pneumonia also can be caused by the flu virus itself. Symptoms of complications will usually appear after you start feeling better.
Pneumonia can be a very serious and sometimes life-threatening condition.
If you have any of these symptoms, you should contact your doctor immediately so that you can get the appropriate treatment. Reye's syndrome, a condition that affects the nerves, sometimes develops in children and adolescents who are recovering from the flu. The syndrome often begins in young people after they take aspirin to get rid of fever or pain. Although very few children develop Reye's syndrome, you should consult a doctor before giving aspirin or products that contain aspirin to children. Acetaminophen does not seem to be associated with Reye's syndrome.