zanamivir (Rx)

Brand and Other Names:Relenza

Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

inhalation powder

  • 5mg (20 units per Rotadisk)

Influenza A & B, Prophylaxis

Household setting: 10 mg inhaled qDay for 10 days

Initiate within 36 hours of exposure

Community outbreaks: Begin within 5 days of outbreak; may administer for up to 28 days

Influenza A & B, Treatment

Start within 2 days of symptom onset; administer 2 doses on day 1, at least 2 hours apart

10 mg inhaled q12hr for 5 days; may consider longer treatment for patients severely ill after 5 days

Influenza H1N1 (Swine Flu) Prophylaxis (Off-label)

10 mg inhaled qDay for 10 days

Initiate within 7 days of exposure

Influenza H1N1 (Swine Flu) Treatment (Off-label)

Start within 2 days of symptom onset; administer 2 doses on day 1, at least 2 hours apart

10 mg inhaled q12hr for 5 days; may consider longer treatment for patients severely ill after 5 days

Dosage Forms & Strengths

inhalation powder

  • 5mg (20 units per Rotadisk)

Influenza A & B, Prophylaxis

Household setting, >5 years: 10 mg inhaled qDay for 10 days; initiate within 48 hours of exposure

Community outbreak, 12-16 years: 10 mg inhaled qDay for 28 days; initiate within 5 days of outbreak

Influenza A & B, Treatment

>7 years: 10 mg inhaled q12hr for 5 days

Start within 2 days of symptom onset; administer 2 doses on day 1, at least 2 hours apart

Influenza H1N1 (Swine Flu) Prophylaxis (Off-label)

Household setting, >5 years old: 10 mg inhaled qDay for 10 days; initiate within 48 hours of exposure

Community outbreak, 12-16 years old: 10 mg inhaled qDay for 28 days; initiate within 5 days of outbreak

Influenza H1N1 (Swine Flu) Treatment (Off-label)

>7 years old: 10 mg inhaled q12hr for 5 days

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Adverse Effects

>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

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Warnings

Contraindications

Hypersensitivity to zanamivir or formulation, including milk proteins

Cautions

Administer only via the Diskhaler inhaler

Allergic-like reactions, including oropharyngeal edema, serious skin rashes, and anaphylaxis reported in postmarketing experience; stop therapy and institute appropriate treatment if an allergic reaction occurs or is suspected

Safety and efficacy have not been demonstrated in patients with high-risk underlying medical conditions; no information is available regarding treatment of influenza in patients with any medical condition sufficiently severe or unstable to be considered at imminent risk of requiring inpatient management

Serious bacterial infections may begin with influenza-like symptoms or may coexist with or occur as complications during the course of influenza; this drug has not been shown to prevent such complications

Effective and safe use of the Diskhaler requires proper use to inhale the drug; prescribers should carefully evaluate ability of young children to use delivery system if use is considered

Do not make into an extemporaneous solution for administration by nebulization or mechanical ventilation; fatality reports of hospitalized patients with influenza who received a solution made with Relenza Inhalation Powder administered by nebulization or mechanical ventilation; lactose in this formulation obstructs proper functioning of the equipment

Most effective when used within 24-48 hr of onset of symptoms

Bronchospasm

  • Not recommended for treatment or prophylaxis of influenza in individuals with underlying airway diseases (eg, asthma, COPD); serious cases of bronchospasm, including fatalities, in patients with or without underlying airways disease reported during treatment
  • Discontinue therapy in any patient who develops bronchospasm or experience decline in respiratory function; immediate treatment and hospitalization may be required
  • Some patients without prior pulmonary disease may have respiratory abnormalities from acute respiratory infection that could resemble adverse drug reactions or increase patient vulnerability to adverse drug reactions
  • If use is considered for patient with underlying airway disease, carefully monitor respiratory function, closely observe patient, and have supportive therapy (ie, fast-acting bronchodilators) immediately available

Neuropsychiatric events

  • Influenza can be associated with a variety of neurologic and behavioral symptoms which can include events such as seizures, hallucinations, delirium, and abnormal behavior, in some cases resulting in fatal outcomes; these events may occur in the setting of encephalitis or encephalopathy but can occur without obvious severe disease
  • There have been postmarketing reports of delirium and abnormal behavior leading to injury in patients with influenza who were receiving therapy; because these events were reported voluntarily during clinical practice, estimates of frequency cannot be made, but they appear to be uncommon
  • These events were reported primarily among pediatric patients and often had an abrupt onset and rapid resolution; the contribution to these events has not been established; patients with influenza should be closely monitored for signs of abnormal behavior
  • If neuropsychiatric symptoms occur, the risks and benefits of continuing treatment should be evaluated for each patient

Drug interactions overview

  • Live attenuated influenza vaccine (LAIV) intranasal has not been evaluated; however, because of potential interference between these products, LAIV should not be administered within 2 weeks before or 48 hours after administration of this drug, unless medically indicated; the concern about possible interference arises from the potential for antiviral drugs to inhibit replication of live vaccine virus
  • Trivalent inactivated influenza vaccine can be administered at any time relative to use of this drug
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Pregnancy & Lactation

Pregnancy

Available data from published studies suggest that use during pregnancy is not associated with an increased risk of birth defects or adverse maternal or fetal outcomes; however, these studies are limited by their small sample sizes, which preclude a definitive assessment of the risk; there are risks to mother and fetus associated with influenza infection in pregnancy; in animal reproduction studies, no adverse developmental effects were observed with intravenous or subcutaneous administration of zanamivir at exposures 300 and 150 times, respectively, the systemic exposure at the maximum recommended human inhalation dose (MRHID) of 10 mg twice daily

Pregnant women are at higher risk of severe complications from influenza, which may lead to adverse pregnancy and/or fetal outcomes, including maternal death, stillbirths, birth defects, preterm delivery, low birth weight,and small for gestational age

Lactation

There are no data on presence of zanamivir in human milk or effects on milk production; there are data from adults that have shown low oral bioavailability of zanamivir; limited data from postmarketing case reports have not suggested a safety concern in infants exposed to breast milk of mothers receiving therapy; drug was present in milk of lactating rats without effect on nursing pups; developmental and health benefits of breastfeeding should be considered along with mother’s clinical need for therapy and any potential adverse effects on breastfed child from drug or underlying maternal condition

Pregnancy Categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.

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Pharmacology

Mechanism of Action

Inhibits viral neuraminidases; stops release of virus from cells & prevents virus from crossing mucous lining of respiratory tract

Pharmacokinetics

Absorption: Inhalation: 4-17%

Protein binding: <10%

Metabolism: None

Half-life: 2.5-5.1 hr

Excretion: Urine (as unchanged drug); feces (unabsorbed drug)

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Images

BRAND FORM. UNIT PRICE PILL IMAGE
Relenza Diskhaler inhalation
-
5 mg/actuation aerosol

Copyright © 2010 First DataBank, Inc.

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Patient Handout

Patient Education
zanamivir inhalation

ZANAMIVIR INHALER - ORAL INHALATION

(za-NAM-i-vir)

COMMON BRAND NAME(S): Relenza

USES: Zanamivir is used to treat symptoms caused by the flu virus (influenza) if you have had symptoms for 2 days or less. It helps lessen symptoms (such as stuffy nose, cough, sore throat, fever/chills, headache, body aches, tiredness) and shortens the recovery time by about 1 to 2 days.Zanamivir may also be used to prevent the flu if you have been exposed to someone who already has the flu (such as a sick household member) or if there is a flu outbreak in the community. Talk to your doctor for more details.This medication works by stopping the flu virus from growing. It is not a substitute for the flu vaccine.If you have the flu, zanamivir does not reduce the risk of giving the flu to others.

HOW TO USE: Read the Patient Information Leaflet provided by your pharmacist before you start using zanamivir and each time you get a refill. Learn all usage instructions. If you have any questions, ask your doctor or pharmacist.For flu treatment: inhale this medication through your mouth as directed by your doctor, usually 2 inhalations (1 blister per inhalation) twice a day (about 12 hours apart) for 5 days. If possible, on the first day of treatment, take two doses (2 inhalations each), waiting at least 2 hours between doses.For flu prevention: inhale this medication through your mouth as directed by your doctor, usually 2 inhalations (1 blister per inhalation) once a day. The usual length of time you will take zanamivir is 10 days if there is a sick household member or 28 days if there is a flu outbreak in the community, or as directed by your doctor.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 all the way 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.Do not mix this powder medication with any liquids, including nebulizer liquids.If a child is using this medication, a parent or other responsible adult should supervise the child to make sure it is used properly.Start zanamivir as soon as possible. This medication works best when the amount of medicine in your body is kept at a constant level. Use this drug at evenly spaced intervals at the same time(s) every day.Continue to use this medication for the full time prescribed, even if symptoms improve. Stopping the medication too early may result in a return of the infection, or failure to protect you from the flu.If you have breathing problems (such as asthma, chronic obstructive pulmonary disease-COPD) and are scheduled to use inhaled bronchodilators (such as albuterol) at the same time as zanamivir, use the bronchodilator medication before using zanamivir. Ask your doctor or pharmacist for more details.Tell your doctor if your condition lasts or gets worse or if new symptoms appear.

SIDE EFFECTS: Dizziness may occur. Also, because this medication is an inhaled powder, you may experience increased coughing after using it. If either of these effects lasts or gets worse, tell your doctor or pharmacist promptly.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.This medication can cause breathing problems, which in rare cases can be fatal. If you experience trouble breathing such as wheezing or shortness of breath, stop using zanamivir and get medical help right away. Zanamivir is not recommended if you have lung/breathing problems. Discuss the risks and benefits with your doctor. However, if your doctor decides you should use zanamivir, have a quick-relief inhaled bronchodilator (such as albuterol inhaler) readily available.The flu itself or zanamivir may rarely cause serious mental/mood changes. This may be more likely in children. Tell your doctor right away of any signs of unusual behavior, including confusion, agitation, self-injury.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: Before using zanamivir, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients (such as lactose, milk proteins), which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: lung or breathing problems (such as asthma, chronic obstructive pulmonary disease-COPD).This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).This drug may be less effective for young children. They may be unable to breathe in deeply enough using this inhaler device to get enough drug to benefit them.During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.It is unknown if this drug passes into breast milk. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Tell your doctor if you have received flu vaccine in the nose in the past 2 weeks. If given too closely together, zanamivir may interfere with the protection from flu vaccine given in the nose. Wait at least 2 days after the end of zanamivir treatment before receiving flu vaccine given in the nose.

OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.

NOTES: Do not share this medication with others.This medication has been prescribed for your current condition only. Do not use it later for another infection unless your doctor tells you to.This medication is not a substitute for the flu vaccine. Consult your doctor about the risks and important benefits of receiving a yearly flu shot to lower your chances of getting the flu.

MISSED DOSE: If you miss a dose, use it as soon as you remember. Do not use the missed dose if it is within 2 hours of your next dose. In that case, skip the missed dose. Use your next dose at the regular time. Do not double the dose to catch up.

STORAGE: Store at room temperature in a dry place. Do not puncture the foil blister until you are ready to take your dose. Do not store in the bathroom. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

Information last revised April 2022. Copyright(c) 2023 First Databank, Inc.

IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.

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Formulary

FormularyPatient Discounts

Adding plans allows you to compare formulary status to other drugs in the same class.

To view formulary information first create a list of plans. Your list will be saved and can be edited at any time.

Adding plans allows you to:

  • View the formulary and any restrictions for each plan.
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  • Compare formulary status to other drugs in the same class.
  • Access your plan list on any device – mobile or desktop.

The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

Tier Description
1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
NC NOT COVERED – Drugs that are not covered by the plan.
Code Definition
PA Prior Authorization
Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
QL Quantity Limits
Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
ST Step Therapy
Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
OR Other Restrictions
Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.