Zanamivir

>10%

Headache (13-24%)

Throat/tonsil pain (8-19%)

Cough ( 7-17%)

Viral infection (3-13%)

>1%

Dizziness (2%)

Nausea (3%)

Diarrhea (3% adults, 2% children)

Vomiting (1% adults, 2% children)

Sinusitis (3%)

Bronchitis (2%)

Infection (ear, nose, & throat; 2% adults, 5% children)

<1%

Malaise

Fatigue

Fever

Abdominal pain

Myalgia

Arthralgia

Urticaria

Postmarketing Reports

Allergic Reactions: Allergic or allergic-like reaction, including oropharyngeal edema

Psychiatric: Delirium, including symptoms such as altered level of consciousness, confusion, abnormal behavior, delusions, hallucinations, agitation, anxiety, nightmares

Cardiac: Arrhythmias, syncope.

Neurologic: Seizures, vasovagal-like episodes shortly after administration

Respiratory: Bronchospasm, dyspnea

Skin: Facial edema; rash, including serious cutaneous reactions (eg, erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis); urticaria

Zanamivir is an antiviral medication. It blocks the actions of viruses in your body.

Zanamivir is used to treat flu symptoms caused by influenza virus in patients who have had symptoms for less than 2 days. Zanamivir may also be given to prevent influenza in people who may be exposed but do not yet have symptoms. Zanamivir will not treat the common cold.

Zanamivir should not be used in place of getting a yearly flu shot. The Centers for Disease Control recommends an annual flu shot to help protect you each year from new strains of influenza virus.

Zanamivir may also be used for purposes not listed in this medication guide.

Zanamivir should not be used in place of getting a yearly flu shot. The Centers for Disease Control recommends an annual flu shot to help protect you each year from new strains of influenza virus.

Before using zanamivir, tell your doctor if you have asthma, chronic obstructive pulmonary disease (COPD), or any other chronic lung condition. Serious or life-threatening bronchospasm (difficulty breathing) and other effects on the lungs can occur while using zanamivir. Stop using zanamivir and call your doctor at once if you have wheezing or severe breathing problems.

Do not use a nebulizer or ventilator to give zanamivir. Zanamivir inhalation powder should never be mixed with a liquid.

Treatment with zanamivir should start as soon as possible when flu symptoms appear, such as fever, chills, muscle aches, sore throat, and runny or stuffy nose.

Do not use this medication to treat flu symptoms in a child younger than 7 years old. Children as young as 5 years old may use the medication to prevent flu symptoms.

Do not use an inhaled nasal flu vaccine (FluMist) within 2 weeks before or 48 hours after using zanamivir. Zanamivir may interfere with the drug action of FluMist, making the vaccine less effective. Follow your doctor's instructions.

Some people using zanamivir have had rare side effects of confusion, delirium and self-injury. These symptoms have occurred most often in children. It is not known whether zanamivir was the exact cause of these symptoms. However, anyone using zanamivir should be watched closely for signs of confusion or unusual behavior. Call a doctor at once if you or the child using zanamivir has any of these symptoms.

You should not use this medication if you are allergic to zanamivir or to lactose (milk protein).

Before using zanamivir, tell your doctor if you have asthma, chronic obstructive pulmonary disease (COPD), or any other chronic lung condition. Serious or life-threatening bronchospasm (difficulty breathing) and other effects on the lungs can occur while using zanamivir.

If you have asthma, COPD, or other chronic lung disease, make sure you have a fast-acting inhaled bronchodilator available to treat any serious breathing problems that may occur while using zanamivir. Fast-acting bronchodilators include albuterol (Ventolin, Proventil), bitolterol (Tornalate), metaproterenol (Alupent), and pirbuterol (Maxair). Talk with your doctor about which medicine is best for you.

If you are scheduled to use a bronchodilator at the same time as zanamivir, use the bronchodilator first.

FDA pregnancy category C. It is not known whether zanamivir will harm an unborn baby. Tell your doctor if you are pregnant. Your doctor will decide whether you should receive zanamivir, especially if you have a high risk of infection with influenza.

It is not known whether zanamivir passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

Do not use this medication to treat flu symptoms in a child younger than 7 years old. Children as young as 5 years old may use the medication to prevent flu symptoms.

Zanamivir is part of the drug class:

• Neuraminidase inhibitors

Some patients have had bronchospasm (wheezing) or serious breathing problems when they used zanamivir. Many but not all of these patients had previous asthma or chronic obstructive pulmonary disease. Zanamivir has not been shown to shorten the duration of influenza in people with these diseases. Because of the risk of side effects and because it has not been shown to help them, zanamivir is not recommended for people with chronic respiratory disease such as asthma or chronic obstructive pulmonary disease.

If you develop worsening respiratory symptoms such as wheezing or shortness of breath, stop using zanamivir and contact your healthcare provider right away.

If you have chronic respiratory disease such as asthma and chronic obstructive pulmonary disease and your healthcare provider has prescribed zanamivir, you should have a fast-acting, inhaled bronchodilator available for your use. If you are scheduled to use an inhaled bronchodilator at the same time as zanamivir, use the inhaled bronchodilator before using zanamivir.

You should not take zanamivir if you are allergic to zanamivir or any other ingredient of zanamivir. Also tell your healthcare provider if you have any type of chronic condition including lung or heart disease, if you are allergic to any other medicines, milk proteins or other food products, or if you are pregnant.

Zanamivir was not effective in reducing the chance of getting the flu in 2 studies in nursing home patients.

Zanamivir does not treat flu-like illness that is not caused by influenza virus.

Tell your doctor if you are allergic to zanamivir or any other medicines.

Tell your doctor if you:

• are pregnant or breastfeeding.
• have asthma or other breathing problems
• have heart, kidney, or liver disease

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements.

If you take too much zanamivir, call your local Poison Control Center or seek emergency medical attention right away.

Use exactly as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended. Follow the directions on your prescription label.

Treatment with zanamivir should start as soon as possible when flu symptoms appear, such as fever, chills, muscle aches, sore throat, and runny or stuffy nose.

Zanamivir is packaged in disk-shaped foil packs that contain 4 blisters of medicine. These disks are placed into a device called a DISKHALER that you will use to inhale the medicine. The device opens and loads a blister of zanamivir each time you use the inhaler. The disk device is not to be used with a spacer. Follow the patient instructions provided with the DISKHALER.

Do not use a nebulizer or ventilator to give zanamivir. Zanamivir inhalation powder should never be mixed with a liquid.

Do not use any other medicines in the DISKHALER. Always put the cover back on the device when not in use.

To treat flu symptoms: Use 2 inhalations every 12 hours for 5 days. Your doctor may tell you to use two doses on the first day of treatment, spaced at least 2 hours apart. On the following days, the doses should be spaced 12 hours apart. Follow your doctor's instructions.

To prevent flu symptoms: Use 2 inhalations every 24 hours for 10 to 28 days. Follow your doctor's instructions.

If you have a chronic respiratory disease such as asthma or COPD and you are scheduled to use an inhaled bronchodilator at the same time as zanamivir, use the inhaled bronchodilator before using zanamivir.

Use this medication for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Tell your doctor if your symptoms do not improve, or if they get worse.

Store at room temperature away from moisture and heat. Throw away the DISKHALER after your treatment ends.

Treatment of Seasonal Influenza A and B Virus Infections

Symptomatic treatment of uncomplicated acute illness caused by susceptible influenza A or B viruses in adults, adolescents, and children ≥7 years of age who have been symptomatic for ≤2 days.1 3 4 5 6 14 105 112 116 144

Efficacy for treatment of influenza not established in patients with underlying airways disease (e.g., asthma, COPD).1 Because of risk of serious bronchospasm, not recommended in those with underlying airways disease.1 (See Individuals with Asthma or COPD under Cautions.) No evidence that treatment with the drug reduces risk of transmission of influenza to others.1

CDC, US Public Health Service Advisory Committee on Immunization Practices (ACIP), AAP, and others recommend antiviral treatment initiated as soon as possible in all individuals with suspected or confirmed influenza who require hospitalization or have severe, complicated, or progressive illness (regardless of vaccination status or underlying illness).105 112 116 137 144 Early empiric antiviral treatment also recommended in individuals with suspected or confirmed influenza of any severity if they are at high risk of developing influenza-related complications because of age or underlying medical conditions.112 116 137 144 This includes children <2 years of age, adults ≥65 years of age, individuals of any age with certain chronic medical or immunosuppressive conditions, women who are pregnant or up to 2 weeks postpartum, individuals <19 years of age who are receiving long-term aspirin therapy, American Indians or Alaskan natives, morbidly obese individuals with body mass index (BMI) ≥40, and residents of any age in nursing homes or other long-term care facilities.112 116 137

CDC, ACIP, and AAP also state empiric antiviral treatment can be considered in previously healthy, symptomatic individuals with suspected or confirmed influenza who are not known to be at increased risk of developing severe or complicated illness if such treatment can be initiated within 48 hours of illness onset.105 112 137 144 Although these individuals typically do not require treatment, early empiric antiviral treatment might provide some benefit (e.g., shortened duration of illness).144

If indicated, initiate treatment with an appropriate antiviral as early as possible since benefit is greatest if started within 48 hours of symptom onset.105 112 137 144 Because there is some evidence that antiviral treatment initiated up to 96 hours after illness onset might still be beneficial in reducing morbidity and mortality in hospitalized patients and in those with severe, complicated, or progressive illness, some experts state that antiviral treatment can be initiated >48 hours after illness onset in such patients.137 144 Do not delay initiation of treatment while waiting for laboratory confirmation.112 137 144

When treatment of seasonal influenza indicated, oseltamivir or zanamivir usually recommended.112 137 144 Oseltamivir usually preferred for hospitalized patients and patients with severe or complicated influenza since data are lacking regarding use of inhaled zanamivir in such patients.161

CDC states that use of investigational IV zanamivir† may be considered for hospitalized patients with severe influenza if they cannot tolerate or absorb oral oseltamivir (e.g., because of suspected or known gastric stasis, malabsorption, GI bleeding) or have infections caused by oseltamivir-resistant strains.161 Although safety and efficacy of IV zanamivir not established, an investigational aqueous solution for IV administration may be available either by enrollment in an ongoing clinical trial or under an emergency investigational new drug (EIND) protocol.161 (See Administration under Dosage and Administration.)

Consider viral surveillance data available from local and state health departments and the CDC when selecting an antiviral for treatment of seasonal influenza.112 137 144 Strains of circulating influenza viruses and the antiviral susceptibility of these strains constantly evolve;144 emergence of zanamivir-resistant influenza virus may decrease effectiveness of the drug.1 Although influenza A and B viruses circulating in US during last few years generally have been susceptible to zanamivir, consult most recent information.137 144

CDC issues recommendations concerning use of antivirals for treatment of influenza, and these recommendations are updated as needed during each influenza season.137 144 Information regarding influenza surveillance and updated recommendations for treatment of seasonal influenza are available from CDC at .

Prevention of Seasonal Influenza A and B Virus Infections

Prophylaxis of influenza caused by influenza A or B viruses in adults, adolescents, and children ≥5 years of age.1 2 17 18 105 112 116 137 144

Safety and efficacy established for prophylaxis of influenza in household settings and during community outbreaks;1 2 17 18 manufacturer states efficacy not established for prophylaxis of influenza in nursing home settings.1

Because of risk of serious bronchospasm, not recommended in those with underlying airways disease (e.g., asthma, COPD).1 (See Individuals with Asthma or COPD under Cautions.)

Annual vaccination with seasonal influenza virus vaccine, as recommended by ACIP, is the primary means of preventing seasonal influenza and its severe complications.100 105 112 116 144 488 Prophylaxis with an appropriate antiviral active against circulating influenza strains is considered an adjunct to vaccination for control and prevention of influenza.1 105 112 116 137 144 488

Indiscriminate use of antivirals for prophylaxis may promote resistance or reduce availability of antivirals for treatment.137 144 Base decisions regarding use of antivirals for prophylaxis of influenza on exposed person's risk for influenza complications, vaccination status, type and duration of contact, recommendations from local or public health authorities, and clinical judgment.144 Generally use postexposure prophylaxis only if it can be initiated within 48 hours of most recent exposure.137 144

When seasonal influenza viruses are circulating in the community, postexposure prophylaxis with oseltamivir or zanamivir can be considered for certain individuals, including those at high risk of developing influenza complications for whom influenza vaccine is contraindicated, unavailable, or expected to have low efficacy (e.g., immunocompromised individuals).112 116 137 144 Other possible candidates for antiviral prophylaxis include unvaccinated health care personnel, public health workers, and first responders with unprotected, close-contact exposure to a patient with confirmed, probable, or suspected influenza during the time when the patient was infectious.112 137 144 Also consider antiviral prophylaxis for controlling influenza outbreaks in nursing and long-term care facilities or other closed or semi-closed settings with large numbers of individuals at high risk for influenza complications.112 116 137 144 In individuals at high risk of influenza complications who receive parenteral inactivated influenza vaccine, prophylaxis can be considered during the 2 weeks after vaccination to provide protection until an adequate immune response develops.112 116 (See Influenza Virus Vaccines under Interactions.)

Consider viral surveillance data available from local and state health departments and the CDC when selecting an antiviral for prophylaxis of influenza.112 137 The most appropriate antiviral for prevention of influenza is based on the likelihood that the influenza strain is susceptible and the known adverse effects of the drug.137 144 Strains of circulating influenza viruses and the antiviral susceptibility of these strains constantly evolve;137 144 emergence of zanamivir-resistant influenza virus may decrease effectiveness of the drug.1

CDC issues recommendations concerning use of antivirals for prophylaxis of influenza, and these recommendations are updated as needed during each influenza season.137 144 Information regarding influenza surveillance and updated recommendations for prevention of seasonal influenza are available from CDC at .

Avian Influenza A Virus Infections

Treatment or prevention of infections caused by susceptible avian influenza A viruses†.50 94 104

CDC and WHO state that oseltamivir is drug of choice for treatment or prophylaxis of infections caused by highly pathogenic avian influenza A (H5N1);50 68 94 104 zanamivir is an alternative.50 94

Oseltamivir also is drug of choice for treatment of infections caused by avian influenza A (H7N9), especially in hospitalized patients and patients with severe or complicated illness.50 Because of limited data, zanamivir not recommended for treatment of severe avian influenza A (H7N9) infections, but may be considered in uncomplicated infections.50 Either oseltamivir or zanamivir can be used for prophylaxis in close contacts of patients with confirmed or probable avian influenza A (H7N9) infection.50

Consider use of investigational IV zanamivir† for hospitalized patients with severe influenza A (H7N9) infection who cannot tolerate or absorb oral oseltamivir (e.g., because of suspected or known gastric stasis, malabsorption, GI bleeding) or have infections caused by oseltamivir-resistant strains.50 (See Administration under Dosage and Administration.)

Pandemic Influenza

Treatment or prevention of pandemic influenza† caused by susceptible strains of influenza virus.52 151

Influenza viruses can cause pandemics, during which rates of illness and death from influenza-related complications can increase dramatically worldwide.52 104 488

Most recent influenza pandemic occurred during 2009 and was related to a novel influenza A (H1N1) strain, influenza A (H1N1)pdm09.52 100 134 144 151 488 In the US, the pandemic was characterized by a substantial increase in influenza activity that peaked in late October and early November 2009 and returned to seasonal baseline levels by January 2010.123 488 During that time, >99% of influenza viruses circulating in the US were influenza A (H1N1)pdm09.123 488 In August 2010, the WHO declared that the world was in a post-pandemic period;148 since that time, influenza A (H1N1)pdm09 has become a seasonal influenza virus and continues to circulate with other seasonal viruses.144 551 553

The spread of the highly pathogenic H5N1 strain of avian influenza A in poultry in Asia and other countries that was first identified in 2003 represents a potential future pandemic threat.28 50 54 55 56 104 147

Zanamivir not metabolized by and does not affect CYP enzymes, including CYP1A1, 1A2, 2A6, 2C9, 2C18, 2D6, 2E1, or 3A4.1 Drug interactions with drugs that are substrates or inhibitors of these enzymes unlikely.1

Specific Drugs

• Tell all of your health care providers that you take this medicine. This includes your doctors, nurses, pharmacists, and dentists.
• This medicine is not to be taken in place of a flu shot. If your doctor told you to get the flu shot, you need to get it.
• This medicine does not treat the common cold.
• This medicine does not stop the spread of the flu to others.
• Talk with your doctor before getting a flu vaccine after taking zanamivir. Talk with your doctor before you take this medicine if you have just gotten a flu vaccine.
• Some people have had very bad breathing problems with zanamivir. Most of the people who had this problem had asthma or other breathing problems like COPD, but some did not. Sometimes, this has been deadly. Talk with the doctor.
• Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using this medicine while you are pregnant.
• Tell your doctor if you are breast-feeding. You will need to talk about any risks to your baby.

Hypersensitivity to zanamivir or any component of the formulation (contains milk proteins)

Refer to adult dosing.

Oral inhalation: Must be used with Diskhaler delivery device. The foil blister disk containing zanamivir inhalation powder should not be manipulated, solubilized, or administered via a nebulizer. Patients scheduled to use an inhaled bronchodilator at the same time as zanamivir should use their bronchodilator prior to zanamivir. With the exception of the initial dose when used for treatment, administer at approximately the same time each day.