context: Antiviral drugs are prescription medications that may help prevent flu complications or shorten the severity and duration of flu once you have it. Here are the latest antiviral drug recommendations. After you read this, talk to your doctor to see if antiviral drugs can help you feel better. Antiviral drugs are medicines that decrease the ability of flu viruses to reproduce. When used as directed, antiviral drugs may help reduce the duration of flu symptoms in otherwise healthy children and adults and may reduce the severity of common flu symptoms. Antiviral drugs are recommended for both treatment and prevention of flu. Antiviral drugs work best when taken within 48 hours of onset of flu symptoms, but they may still offer benefits when taken later. These medications may reduce the duration of flu by one to two days and prevent severe flu complications. Your doctor may prescribe an antiviral if you come in close contact with family members or others who have the flu and you want to try to avoid getting sick. However, the CDC discourages this as a routine practice, as it can lead to drug-resistant strains of the virus. Instead, the CDC recommends that people at risk of severe flu -- such as pregnant women or people with asthma, diabetes, or heart disease -- begin antiviral treatment as soon as flu symptoms appear. Others at high risk for complications from the flu include infants, the elderly, those with chronic illness, Native Americans and Alaskan Natives It's important, however, to remember that vaccination is the most effective way to prevent flu. The CDC recommends the antiviral drugs baloxavir marboxil ( Xofluza), oseltamivir ( Tamiflu), and zanamivir ( Relenza) for both flu prevention and treatment.. Baloxavir marboxil is taken orally and is approved for use in treatment of children 12 years of age and older. Oseltamivir, which is taken by mouth, is approved for treating flu in those over 2 weeks of age and preventing flu in people one year of age and older. Peramivir, given in one intravenous dose, is approved for people over the age of 2 for treatment only. Zanamivir is approved for treating flu in people 7 years and older and for preventing flu in people 5 years and older. Relenza is inhaled through the mouth. All four antivirals are most effective when given within 48 hours of the onset of flu symptoms, although they may still prevent severe flu complications when given more than 48 hours after symptoms appear. For in-depth information, see Web MD's Flu Prevention Strategies. Side effects of antivirals may include nausea, vomiting, runny nose, stuffy nose, cough, diarrhea, and behavioral changes. Zanamivir is not recommended for individuals who have asthma, chronic obstructive pulmonary disease ( COPD), or other lung disease. Based on your individual health status, your doctor will prescribe the antiviral drug that's safest for you. Ideally, you should talk to your doctor about the flu vaccine and antiviral drugs, including side effects, before the flu season begins. When you do get flu symptoms, it's important to call your doctor soon after symptoms appear. Flu drugs are most effective when taken within the first 48 hours of flu symptoms, although they may help prevent severe disease when taken later.