Zanamivir Oral Inhalation

Zanamivir is a prescription approved by the Food and Drug Administration (FDA). This is a type of medicine called a neuraminidase inhibitor used to treat and prevent influenza type A or B. Zanamivir helps stops the flu virus from spreading around the body. This medication is usually used in adults and children aged five years and over. 

Influenza is a viral infection that attacks your respiratory system. For most people, influenza resolves on its own. Initially, the flu may seem like a common cold. But, colds usually develop slowly whereas the flu tends to come on suddenly. The common signs and symptoms of influenza are:

  • Aching muscles
  • Headache
  • Chills and sweats
  • Fatigue 
  • Weakness
  • Dry and persistent cough
  • Sore throat
  • Nasal congestion 
  • Fever over 100.4 F or 38 C 

People at higher risk of developing flu complications may include:

  • Adults older than age 65
  • Young children under age 5 
  • Pregnant women 
  • Residents of nursing homes 
  • People with a weakened immune system
  • People who are very obese
  • People with chronic illnesses (diabetes, asthma, kidney/liver disease, or heart disease)

Flu viruses travel through the air in droplets when someone with the infection sneezes or coughs. You can inhale the droplets directly or you can pick up the germs from an object. People with viruses are likely contagious from the day or so before symptoms first appear. The viruses of influenza are constantly changing with new strains appearing regularly. If you’ve had influenza in the past, your body has already made antibodies to fight that particular strain of the virus. If future influenza viruses are similar to those you’ve encountered before, those antibodies may prevent infection or lessen its severity. It’s either by having the disease or by being vaccinated. But, antibodies against flu viruses you’ve encountered in the past can’t protect you from new influenza strains. Those can be very different immunologically from what you had before. 

How does Zanamivir work for flu?

When the flu virus enters the body, it invades cells in the airways. Wherein, it replicates to form lots of new copies of the virus. The new copies of the virus leave the first cells and move on to infect neighboring cells. It is where exactly the process is being repeated. After a couple of days, enough cells have been infected that the patient feels flu symptoms. The symptoms usually continue for about a week until the immune system of the body kills the virus. 

To leave one cell and infect another, the flu virus uses a chemical helper called neuraminidase. Zanamivir works by stopping this chemical helper from working. Without it, newly formed copied of the virus can’t leave the infected cells to infect other cells. This prevents the flu virus from spreading and so confines the infection to a smaller area. This makes the symptoms of the infection less severe. It also makes it easier for the immune system of the body to kill the virus. 

How to use Zanamivir?

For flu treatment

Inhale this medication through your mouth usually 2 inhalations twice a day for 5 days or as directed by your doctor. If possible, on the first day of treatment, take two doses, waiting at least 2 hours between doses. 

For flu prevention

Inhale the medication by your mouth usually 2 inhalations once a day or as directed by your doctor. The usual length time of this medicine that you will take is 10 days if there is a sick household member.  

Remove the cover on the disk inhaler. Before use, check the mouthpiece to be sure it is clean and free of particles. Load the medication disk into the disk inhaler. Puncture one medication blister. Keep the disk inhaler level so that the medication will not spill out. Breathe out through your mouth, put the mouthpiece into your mouth, and breathe in through your mouth as deeply as you can. This will draw the medication into your lungs. Hold your breath for a few seconds. To take another inhalation, advance to the next medication blister and repeat the process. Replace the cover of the disk inhaler. Carefully read the manufacturer’s instructions that describe how to prepare and inhale a dose of Zanamivir using the disk inhaler. Be sure to ask your doctor if you have any questions about how to prepare or inhale this medication.

What are the side effects?

Common side effects:

  • Ear pain
  • Cough
  • Wheezing
  • Trouble breathing
  • Nausea
  • Diarrhea
  • Vomiting
  • Headache
  • Dizziness
  • Cold symptoms such as sneezing, stuffy nose, or sore throat 

Call your doctor right away if you have these serious side effects:

  • Trouble speaking
  • Sudden confusion
  • Seizure
  • Tremors or shaking
  • Hallucinations 
  • Nasal irritation 
  • Ear, nose, and throat infections 
  • Sudden unusual changes in mood or behavior 


  • For some people, Zanamivir may cause the airways to narrow after it has been inhaled which makes breathing difficult. If this happens, stop using Zanamivir and call your doctor right away. 
  • If you suffer from COPD or asthma and using a regular bronchodilator, you use it before inhaling your dose of Zanamivir. You should have your reliever at hand when you are taking this drug. 
  • This medication should not be used as a substitute for being vaccinated against seasonal flu. 
  • Zanamivir may be prescribed to women who are pregnant in situations where the potential benefit of taking the medicine outweighs any potential risks. Your doctor can give you more information on what we know about the safety of Zanamivir during pregnancy. 
  • Zanamivir may pass into breast milk in very small amounts. This prescription may be prescribed to women who are breastfeeding if the potential benefit to the mother outweighs any potential risk to the nursing infant. Ask your doctor for advice if you are breastfeeding.
  • Tell your doctor what prescription and non-prescription medications, nutritional supplements, vitamins, and herbal products you are taking or plan to take. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
  • If you forget to inhale a dose, inhale it as soon as you remember it. If it is 2 hours or less until the next dose, skip the missed dose and continue your regular dosing schedule. Do not inhale a double dose to make up for a missed one. If you miss several doses, call your doctor to find out what to do.