Best Flu Medicines & Their Side Effects

The flu or influenza is an infection of the respiratory system caused by a flu virus. Most people recover without taking flu medicine. However, it is possible to take flu pills for symptomatic treatment, that is, to help relieve symptoms and discomfort.

What flu medicines can be taken?

The most effective remedy for the flu is rest, hydration and taking antipyretics for fever, if it causes discomfort. There is no effective treatment or medication for the flu, and taking antibiotics for the flu is not indicated as it is a viral infection. Only on rare occasions, when a bacterial superinfection (such as pneumonia) occurs, can they be prescribed.

The flu is a respiratory infectious disease that is spread very easily through saliva, sneezing or coughing from people around you. It mainly affects the nose, throat and lungs and presents very annoying symptoms such as:

  • High fever
  • Headache
  • Dry cough
  • Muscle and joint pain
  • Sore throat and rhinitis
  • Major general malaise

Most people recover without taking flu medicine.

The body’s immune system usually fights the virus without needing to take flu medicine to cure itself. Infection with more acute symptoms usually lasts a week, and most people recover from the flu in one to two weeks.

Unlike a common cold, there is no way to get out of the flu fast and there is no truly effective flu treatment, as the flu virus changes every year. Medications for the flu are actually those that help us reduce general discomfort, such as paracetamol or ibuprofen to lower high fever or home remedies for flu to lower fever.

However, if you are over 65 years of age or have a weakened immune system (for example, from HIV/AIDS or a chronic illness such as diabetes), a flu infection can become much more serious. There is a risk that you will develop pneumonia (inflammation of the lungs) or other infections and you may need treatment for flu with superinfection.

If you’ve been in contact with someone with the flu and you’re 65 or older, have chronic lung disease, heart disease, chronic kidney disease, diabetes, or have a weakened immune system, you’ll need flu medication to prevent further complications. If you are in that risk group, your doctor will explain what to take for the flu.

In the UK, the National Institute for Health and Clinical Excellence (NICE) has issued recommendations on the specific groups of people who are eligible to receive influenza medicines. Such people include those who:

  • Are 65 or older
  • Have a chronic lung disease, such as asthma
  • Have some heart disease
  • Have chronic renal failure
  • Have diabetes
  • Have a weakened immune system

If you fall into any of these categories, if you have been in contact with someone who has the flu (for example, if you live with that person), and if you are not protected by a flu vaccine, your GP may prescribe flu medications.

These medicines stop viruses from spreading within your body, so they can reduce or sometimes prevent flu symptoms. Flu medications can also reduce the duration of the illness and your risk of developing complications.

However, to be effective, you need to start taking them within 48 hours of your exposure to the virus or the onset of symptoms.

A flu pandemic occurs when a new version of a flu virus appears and spreads easily and rapidly in different parts of the world. Medicines against the virus are sometimes used to treat pandemic flu. However, until a flu pandemic begins, doctors cannot know for sure whether anti-virus drugs will work against that particular virus.

What are the main types of flu medicines?

Best Flu Medicines
zanamivir and oseltamivir.are two flu antiviral drugs currently recommended for prevention and treatment

There are two flu antiviral drugs currently recommended for prevention and treatment: zanamivir and oseltamivir. They work to treat both influenza A and influenza B (the two main types of seasonal influenza viruses).

Another of the flu medications, amantadine, is licensed to prevent aznd treat influenza A, but its use is no longer recommended.

How do flu medicines work?

Zanamivir and oseltamivir are part of a group of flu antiviral drugs called “neuraminidase inhibitors.” When a virus infects a person’s body, it multiplies inside cells. These flu medicines inhibit a protein called “neuramidase.” In this way, the virus is prevented from being released from infected cells and thus the reproduction of the virus within the organism is reduced.

How to take flu medicine?

Zanamivir is available in inhalers, which are similar to those used to treat asthma. Each shot contains a small amount of the medicine. To treat the flu (if you have symptoms), you must use the inhaler twice a day for five days . To prevent the flu after you have been exposed to the disease, you will need to use this flu medicine once a day for ten days. If there is a flu epidemic, you may be prescribed zanamivir for up to 28 days.

Oseltamivir is available as a capsule or syrup. To treat the flu, you will need to take two capsules a day for five days. Doctors prescribe lower doses for children over one year of age, based on their body weight. To prevent the flu, you should take one capsule a day for ten days after being exposed to the virus, or up to six weeks if there is an epidemic.

For oseltamivir and zanamivir to be effective, you need to start taking them within 48 hours after your first symptoms appear.

Special care when taking medicines for the flu

Zanamivir is the flu medicine of choice for pregnant women, and oseltamivir is generally recommended for breastfeeding women.

If you have advanced kidney failure, you may not be able to take oseltamivir.

Always check with your GP before taking flu medicines, and read the patient information leaflet that comes with the medicine.

Side effects of flu medicines

Some of the side effects of the antiviral oseltamivir are as follows:

These side effects usually appear after you take the first dose of the medication and go away as you continue to take it. The chances of getting these side effects from taking flu medicines are reduced if you take oseltamivir with food.

Side effects of the antiviral zanamivir are rare, but may include:

  • Swelling of the face, mouth or throat
  • Rash
  • Difficulty breathing

Because zanamivir can cause shortness of breath, it is generally not recommended for patients with underlying disease that affects the respiratory system. Such diseases include asthma and chronic obstructive neuropathy. Check with your GP for more information.

Resistance to flu drugs

Because the flu virus is constantly changing, strains can appear that are not controlled by antiviral drugs . This phenomenon is called “resistance”.

Since the beginning of 2008, in several European countries, including the United Kingdom, there have been reports of influenza A strains that are resistant to oseltamivir. These resistant strains can still be treated with zanamivir.

Over the counter flu medicine

The following chart shows generic and brand names of flu medicines.

Generic NameBrand Name

Can flu medicines be used as an alternative to the flu vaccine?

No. Flu medicines are not a substitute for the vaccine.

Can I take flu medicine if I am not part of a risk group?

No. It is unlikely that you will be prescribed a flu medication if you are under 65 years of age and in good general health.

Can I buy medicines against the flu virus online?

The flu drugs zanamivir and oseltamivir can be purchased online, often being shipped from other countries. However, be careful if you plan to purchase medications this way. If you buy medicines online, there is a risk that they are coming from unregulated or illegal websites. If so, there will be no guarantee of the safety, quality, or efficacy of the medications you receive.


The flu vaccine is the most effective way to prevent the flu. Medications against the flu virus cannot be used instead of the vaccine.

The flu vaccine is available free of charge to people age 65 and older and is recommended for those who are at risk of flu complications. Groups at risk include adults and children (over six months of age) who have:

If you fall into one of these categories, ask your GP about a flu shot. The usual time to get the flu vaccine is between September and early November, which is usually before the start of the flu season.

Dr. Ashwani Kumar is highly skilled and experienced in treating major and minor general medicine diseases.