Oseltamivir is approved for the treatment of the flu in people aged 2 weeks and older. This medicine can also be taken by pregnant women.

Common side effects include nausea and vomiting. These may happen within the first two days of taking oseltamivir. There is also a risk, especially in children, of unusual behavior (eg, self-injury, confusion). It is important that people who take this medicine be closely monitored.

Zanamivir, which comes in a disk inhaler, is approved for people aged seven years and older who do not have breathing or heart problems. Common side effects include:

• Dizziness
• Sinusitis
• Nasal congestion
• Cough
• Diarrhea
• Nausea
• Headache
• Bronchitis
• Ear, nose, or throat infections

Like oseltamivir, zanamivir may cause unusual behavior, especially in children.

While amantadine (Symmetrel) and rimantadine (Flumadine) are also antivirals, they are in a different drug class than oseltamivir and zanamivir. Amantadine and rimantadine have been prescribed in the past for people with influenza A viruses. However, influenza A viruses have developed a resistance to these medicines, so they are not recommended now.

Most people who get the flu do not need antivirals. Your doctor may recommend these drugs if you:

• Have severe flu symptoms
• Have the flu and are at high risk for serious complications

People who are at high risk include:

• Children younger than five years old (especially those younger than two years)
• Adults aged 50 years and older
• Pregnant women and women who have given birth in the past two weeks
• People with chronic conditions (eg, asthma, heart failure, lung disease) or weakened immune systems (eg, patients with diabetes, patients with HIV infection)
• People aged 18 years and younger who are on long-term aspirin therapy

Antivirals should be taken as early as possible—within the first two days of your illness. In general, the medicine is taken twice a day for five days.

Antivirals can reduce your symptoms and shorten how long you have the flu. If you are hospitalized due to the flu, antivirals may be able to shorten your hospital stay and reduce your risk of complications.

Antivirals can be used to prevent the flu. But the best strategy is to be vaccinated every year! The CDC recommends that everyone aged six months and older get the flu vaccine as soon as it becomes available.