What is zanamivir, and how does it work (mechanism of action)?
Zanamivir is an inhaled drug that is used for treating and preventing influenza (the "flu"). Zanamivir decreases the spread of influenza A and B viruses, the viruses responsible for the flu. It does this by blocking the action of neuraminidase, an enzyme produced by the viruses that enables the viruses to spread from infected cells to healthy cells. By preventing the spread of virus from cell to cell, the symptoms and duration of influenza infection are reduced. On average, zanamivir reduces the duration of symptoms by one day if treatment is started within forty-eight hours after symptoms begin.
- The FDA approved zanamivir in July 1999.
- The brand name for Zanamivir is Relenza.
- Zanamivir is available over-the-counter (OTC).
What are the side effects of zanamivir?
The most frequent side effects are:
Other important side effects include:
- increase or decrease in appetite,
- fever,
- chills,
- weakness,
- sinusitis, and
- ear; nose; and throat infections,
- skin reactions,
- muscle or joint pain,
- allergic reactions,
- bronchospasm, and
- behavioral disturbances.
Patients with respiratory diseases may experience breathing problems when treated with zanamivir due to irritation of the breathing tubes by the particles from the inhaler. If breathing problems occur, zanamivir should be discontinued. Patients who have asthma or other breathing problems that make them sensitive to inhaled particles should have a fast acting, inhaled bronchodilator available to treat any breathing problem that may occur when zanamivir is used.
![](https://images.medicinenet.com//images/slideshow/natural_cold_remedies_s1_woman_blowing_nose_on_couch.jpg)
SLIDESHOW
How to Get Rid of a Cold: Natural Remedies See SlideshowWhat is the dosage for zanamivir?
Zanamivir is administered by oral inhalation. The recommended dose is two inhalations (5 mg per inhalation) twice daily (approximately 12 hours apart) for five days. Two doses (separated by at least two hours) should be administered on the first day of treatment. For best results, treatment should begin as soon as symptoms develop. The recommended dose for prevention of influenza in a household setting is 10 mg once daily for 10 days. The recommended dose for preventing influenza in a community setting is 10 mg once daily for 28 days.
Which drugs or supplements interact with zanamivir?
Zanamivir potentially may interfere with the action of injections of live attenuated flu vaccine because zanamivir prevents viral replication. Therefore, live attenuated flu vaccine should not be administered from 2 weeks before to 48 hours after administration of zanamivir. Trivalent inactivated influenza vaccine can be administered while using zanamivir.
Health News
- STD Specialists Warn of Shortage of Vital Syphilis Drug
- Immediate Body Contact With Parents Helps Preemie Newborns Thrive
- Identical Twins Study Shows Vegan Diets Helping the Heart
- Timing of Menopause Could Affect a Woman's Muscle Loss
- One Food Could Boost Health of Colon Cancer Survivors
More Health News »
Is zanamivir safe to take if I'm pregnant or breastfeeding?
The Centers for Disease Control (CDC) states that pregnancy is not a contraindication for use of zanamivir in pregnant women because the benefits outweigh the risks.
It is not known whether zanamivir is excreted in breast milk. However, the CDC recommends that nursing women who develop flu after child birth should be treated with antiviral drugs.
Summary
Zanamivir (Relenza) is a prescription inhaled medication used to treat and prevent the flu (influenza)including H1N1 (swine flu). Zanamivir (Relenza) decreases and suppresses the spread of influenza A and B viruses (to include H1N1 or swine flu. Side effects, drug interactions, warnings and precautions, and patient information should be reviewed prior to taking any medication.
Multimedia: Slideshows, Images & Quizzes
-
Cold, Flu, and Cough: 13 Foods to Eat When Fighting the Flu
The best foods to eat when you have the flu soothe symptoms and help you feel better faster. Good foods to eat with the flu...
-
Cold, Fever and Flu Symptoms in Children: Medications and Home Remedies
How long does a cold last? How long is a cold contagious? Colds and fevers are some of the most common ailments in children....
-
How to Get Rid of a Cold: Natural Remedies
What home remedies work to get rid of a cold fast? Many claim cold symptoms and flu symptoms can be relieved with Echinacea,...
-
Cold & Flu Quiz: Influenza vs. Common Cold
Aches? Pain? Fever? This Cold & Flu Quiz tests your knowledge on the difference between coming down with the common cold and...
-
Picture of Influenza Virus
The flu is caused by viruses that infect the respiratory tract which are divided into three types, designated A, B, and C. See a...
Related Disease Conditions
-
Flu (Influenza)
Influenza (flu) is a respiratory illness caused by a virus. Flu symptoms include fever, cough, sore throat, runny nose, headache, fatigue, and muscle aches. The flu may be prevented with an annual influenza vaccination.
-
Bird Flu (Avian Influenza, Avian Flu)
Bird flu (avian flu, avian influenza) infection in humans may result from contact with infected poultry. There is a vaccine to prevent human infection with the H5N1 strain of the avian flu virus.
-
Swine Flu (Swine Influenza A [H1N1 and H3N2])
Novel H1N1 influenza A virus infection (swine flu) is an infection that generally is transferred from an infected pig to a human, however there have been reported cases where infection has occured with no contact with infected pigs. Symptoms of swine flu are "flu-like" and include fever, cough, and sore throat. Treatment is generally with the antibiotics oseltamivir (Tamiflu) or zanamivir (Relenza).
Treatment & Diagnosis
- Cold & Flu FAQs
- How To Reduce Your Medication Costs
- Pharmacy Visit, How To Get The Most Out of Your Visit
- Indications for Drugs: Approved vs. Non-approved
- Drugs: The Most Common Medication Errors
- Medication Disposal
- Dangers of Mixing Medications
- Drugs: Buying Prescription Drugs Online Safely
- Swine Flu: One New York City Pediatrician's View
- Swine Flu Symptoms, Diagnosis, and Vaccination
- Flu: What to Do if You Get the Flu
- Generic Drugs, Are They as Good as Brand-Names?
- Influenza A (H3N2)v: What Goes Around Comes Around
Medications & Supplements
Prevention & Wellness
Subscribe to MedicineNet's General Health Newsletter
By clicking Submit, I agree to the MedicineNet's Terms & Conditions & Privacy Policy and understand that I may opt out of MedicineNet's subscriptions at any time.
Health Solutions From Our Sponsors
![FDA Logo](https://images.medicinenet.com/images/logo_fda.png)
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
Relenza FDA Prescribing Information.
CDC.gov. What You Should Know About Flu Antiviral Drugs. September 17, 2013.