Influenza is treated with a combination of antiviral medications and symptom relief, with the most important factor being how quickly treatment begins. Antiviral drugs work best when started within 48 hours of your first symptoms, though they can still help in serious cases even when started later. Most people recover at home with rest, fluids, and over-the-counter medications to manage fever and discomfort.
Antiviral Medications
Four antiviral drugs are currently approved for treating the flu. The most widely prescribed is oseltamivir (Tamiflu), taken as a capsule or liquid twice a day for five days. Adults receive a standard 75 mg dose, while children’s doses are adjusted by body weight. Three other options exist: zanamivir (an inhaled powder), peramivir (given as a single IV dose), and baloxavir (a single oral dose taken just once).
These drugs work in two different ways. Oseltamivir, zanamivir, and peramivir block the virus from escaping infected cells, which slows its spread through your body. Baloxavir takes a different approach, shutting down the virus’s ability to copy its genetic instructions in the first place, which directly reduces the amount of virus in your system. Nearly all circulating flu strains remain susceptible to these medications, so resistance is not a practical concern for most patients right now.
Antivirals don’t cure the flu instantly. They typically shorten your illness by one to two days and reduce the severity of symptoms. For people at high risk of complications, though, that difference can be significant enough to prevent hospitalization.
Why Timing Matters
The 48-hour window after symptoms begin is the sweet spot for starting antiviral treatment. The virus replicates rapidly in those early hours, so the sooner a drug interferes with that process, the less total damage it causes. If you suspect you have the flu, getting a prescription quickly is worth the effort.
That said, missing the 48-hour window doesn’t mean treatment is pointless. Studies of hospitalized patients have found that antivirals can still reduce complications and mortality when started up to four or five days after symptoms appear. One study in children showed that oseltamivir started at 72 hours still shortened symptoms by about a day. The general rule: if you’re otherwise healthy and it’s been more than two days, antivirals may offer limited benefit. If you’re severely ill or in a high-risk group, starting treatment late is still better than skipping it entirely.
Managing Symptoms at Home
Whether or not you take an antiviral, most flu recovery happens at home with over-the-counter medications targeting your worst symptoms. Acetaminophen and ibuprofen bring down fever and ease body aches. For a persistent cough, dextromethorphan (the active ingredient in many cough suppressants) is the most effective widely available option. Nasal congestion responds best to pseudoephedrine. If your symptoms are keeping you awake at night, a first-generation antihistamine can help with sleep while also drying up a runny nose.
Beyond medication, the basics matter more than people expect. Rest gives your immune system the energy it needs to fight the virus. Staying well-hydrated replaces fluids lost through fever and sweating. Water, broth, and electrolyte drinks all work. You don’t need to force large meals, but small amounts of food help maintain your energy.
Most healthy adults feel significantly better within a week, though fatigue and a lingering cough can hang on for another week or two.
Treating Children Safely
Children can take oseltamivir starting at age one, with doses based on their weight. Baloxavir is also approved for children, though age cutoffs vary. The treatment timeline and goals are the same as for adults: start early, manage symptoms, and watch for worsening signs.
One critical safety rule applies to anyone under 18: never give aspirin during the flu. Aspirin use during a viral illness is linked to Reye’s syndrome, a rare but serious condition where the liver swells, blood sugar drops, and dangerous pressure can build in the brain. Children with underlying fatty acid oxidation disorders are especially vulnerable. Use acetaminophen or ibuprofen for fever and pain instead. Check the labels of combination cold medicines too, since some contain aspirin or aspirin-related compounds.
Pregnancy and High-Risk Groups
Pregnant women face a higher risk of flu complications, which is why the CDC recommends starting antiviral treatment on suspicion alone, without waiting for a confirmed test result. Oseltamivir is the preferred drug during pregnancy because it has the most safety data available. The standard five-day course applies, though some evidence suggests pregnant women may need a slightly higher dose because their kidneys clear the drug faster than usual. Baloxavir is not recommended during pregnancy or breastfeeding due to a lack of safety data.
Other high-risk groups, including adults 65 and older, people with asthma or chronic lung disease, heart disease, diabetes, and those with weakened immune systems, should also prioritize early antiviral treatment. For hospitalized patients with severe infections, especially those in intensive care, treatment courses sometimes extend beyond the standard five days.
Warning Signs That Need Emergency Care
Most flu cases resolve on their own, but certain symptoms signal that something more dangerous is happening. In adults, go to the emergency room if you experience difficulty breathing, chest or abdominal pain, sudden dizziness, confusion, severe vomiting, or flu symptoms that seem to improve and then return worse than before. That last pattern, a rebound with worsening fever and cough, can indicate a secondary bacterial infection like pneumonia.
For children, the warning signs include bluish skin or lips, fast or labored breathing, extreme irritability, fewer wet diapers than usual or no tears when crying (signs of dehydration), refusal to eat or drink, or a fever accompanied by a rash. Any of these warrants an immediate ER visit regardless of how many days into the illness your child is.