Zanamivir Oral Inhalation
Zanamivir oral inhalation is an inhaled antiviral that treats and helps prevent influenza (flu) types A and B.
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 2 clinical label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
Relenza (zanamivir) is an inhaled flu antiviral, on the market since about 1999, that treats influenza A and B when started within 2 days of symptoms and can help prevent it; it blocks an enzyme the virus needs to spread, and it is used less often than oral flu medicines. Most people tolerate it well, and the usual complaints are headache, cough or nasal and sinus irritation. The real danger is bronchospasm, a sudden, sometimes fatal tightening of the airways, so it is not recommended with asthma or COPD; stop it and get help right away if breathing worsens or you have an allergic reaction.
Clinical pearls
- Inhale it only through the Diskhaler device it comes with; never mix the powder into a nebulizer or ventilator solution.
- Skip the nasal spray flu vaccine from 2 weeks before until 48 hours after Relenza; the flu shot is fine anytime.
- The powder contains lactose, so a milk protein allergy rules it out.
- Watch children closely for sudden confusion, hallucinations or odd behavior, mostly reported in kids, and call the doctor if it happens.
Patient information guide A plain-language walkthrough of Zanamivir Oral Inhalation, written from its FDA label.
What Zanamivir Oral Inhalation is used for
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Zanamivir oral inhalation is used for influenza A and B.
- Relenza treats uncomplicated, acute flu in adults and children 7 years and older with symptoms for no more than 2 days.
- Relenza helps prevent flu in adults and children 5 years and older.
- It is not a substitute for yearly flu vaccination.
- It does not treat illnesses caused by other germs.
How Zanamivir Oral Inhalation works
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Zanamivir is an antiviral that works against influenza virus. It is a neuraminidase inhibitor. It is inhaled, so it acts mainly in the mouth, throat and lungs.
Flu viruses change over time. Resistance could make the drug work less well.
Zanamivir Oral Inhalation dosage
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Relenza is inhaled through the mouth using the DISKHALER only. Ask for a demonstration of the device.
- Treatment: taken twice a day for 5 days.
- Prevention: taken once a day, for a period that depends on whether it is used in a household or a community outbreak.
- Each dose is two inhalations.
- Use an inhaled bronchodilator first, if you have one.
Follow your prescriber and the label.
Dosing details from the FDA-approved label
From the Zanamivir Oral Inhalation prescribing information (“Dosage and Administration”). Doses are set by your prescriber for your product, condition, kidney function and age — never change a dose on your own.
- Treatment of influenza (adults and pediatric patients aged 7 years and older)
- 10 mg twice daily (approximately 12 hours apart) for 5 days
- The 10-mg dose is provided by 2 inhalations (one 5-mg blister per inhalation)
- Two doses should be taken on the first day whenever possible provided there is at least 2 hours between doses; on subsequent days doses about 12 hours apart
- Prophylaxis of influenza, household setting (adults and pediatric patients aged 5 years and older)
- 10 mg once daily for 10 days
- The 10-mg dose is provided by 2 inhalations (one 5-mg blister per inhalation)
- Administer at approximately the same time each day
- Prophylaxis of influenza, community outbreaks (adults and adolescents)
- 10 mg once daily for 28 days
- The 10-mg dose is provided by 2 inhalations (one 5-mg blister per inhalation)
- Administer at approximately the same time each day; safety and effectiveness not evaluated for longer than 28 days
Read the label’s full dosing text
2 DOSAGE AND ADMINISTRATION Indication Dose Treatment of Influenza ( 2.2 ) 10 mg twice daily for 5 days Prophylaxis: ( 2.3 ) Household Setting 10 mg once daily for 10 days Community Outbreaks 10 mg once daily for 28 days Note: The 10-mg dose is provided by 2 inhalations (one 5-mg blister per inhalation). ( 2.1 ) 2.1 Dosing Considerations • RELENZA is for administration to the respiratory tract by oral inhalation only , using the DISKHALER device provided [see Warnings and Precautions ( 5.6 )] . • The 10-mg dose is provided by 2 inhalations (one 5-mg blister per inhalation). • Patients should be instructed in the use of the delivery system. Instructions should include a demonstration whenever possible. If RELENZA is prescribed for children, it should be used only under adult supervision and instruction, and the supervising adult should first be instructed by a healthcare professional [see Patient Counseling Information ( 17 )] . • Patients scheduled to use an inhaled bronchodilator at the same time as RELENZA should use their bronchodilator before taking RELENZA [see Patient Counseling Information ( 17 )] . 2.2 Treatment of Influenza • The recommended dose of RELENZA for treatment of influenza in adults and pediatric patients aged 7 years and older is 10 mg twice daily (approximately 12 hours apart) for 5 days. • Two doses should be taken on the first day of treatment whenever possible provided there is at least 2 hours between doses. • On subsequent days, doses should be about 12 hours apart (e.g., morning and evening) at approximately the same time each day. • The safety and efficacy of repeated treatment courses have not been studied. 2.3 Prophylaxis of Influenza Household Setting • The recommended dose of RELENZA for prophylaxis of influenza in adults and pediatric patients aged 5 years and older in a household setting is 10 mg once daily for 10 days. • The dose should be administered at approximately the same time each day. • There are no data on the effectiveness of prophylaxis with RELENZA in a household setting when initiated more than 1.5 days after the onset of signs or symptoms in the index case. Community Outbreaks • The recommended dose of RELENZA for prophylaxis of influenza in adults and adolescents in a community setting is 10 mg once daily for 28 days. • The dose should be administered at approximately the same time each day.
Excerpted — the section continues on the label. Read the full Dosage and Administration section on DailyMed →
Zanamivir Oral Inhalation side effects
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Most people tolerate Relenza, but some have side effects.
Common side effects
- Sinusitis (sinus infection or irritation)
- Dizziness
- Fever and/or chills (seen in prevention trials)
- Joint pain (arthralgia)
- Articular rheumatism (joint and muscle aching)
- Diarrhea and nausea
- Headache, cough and nasal symptoms
When to get medical help
- Get help right away if you have wheezing, chest tightness, or trouble breathing. Serious, sometimes fatal, bronchospasm has been reported. Stop Relenza.
- Stop Relenza and get help if you have an allergic reaction, such as swelling in the mouth or throat, a serious skin rash, or trouble breathing.
- Call your doctor if you or your child have seizures, confusion, hallucinations, or unusual behavior during the flu.
- Call your doctor if you get worse or develop symptoms of a bacterial infection. Relenza has not been shown to prevent these complications.
Zanamivir Oral Inhalation warnings and precautions
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- Bronchospasm: serious, sometimes fatal. Not recommended with asthma or COPD. Stop if breathing worsens.
- Allergic reactions: mouth or throat swelling, serious rash, anaphylaxis. Stop and get help.
- Behavior changes: seizures, confusion, hallucinations, delirium, mostly in children with flu. Watch closely.
- Bacterial infections: Relenza does not prevent them.
- Device: never use in a nebulizer or ventilator.
- Treating flu does not reduce the risk of spreading it to others.
Zanamivir Oral Inhalation interactions
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The main interaction is with a live flu vaccine.
- Nasal spray flu vaccine (live attenuated): avoid within 2 weeks before or 48 hours after Relenza, because the antiviral may block the vaccine.
- Flu shot (inactivated): fine at any time.
- Inhaled bronchodilators: use before Relenza.
Interactions listed in the FDA-approved label
From the Zanamivir Oral Inhalation prescribing information (“Drug Interactions”): what the manufacturer studied or reported to the FDA.
- Live attenuated influenza vaccine (LAIV), intranasal: Concurrent use has not been evaluated, but there is potential interference because antiviral drugs may inhibit replication of the live vaccine virus. Do not administer LAIV within 2 weeks before or 48 hours after RELENZA, unless medically indicated.
- Trivalent inactivated influenza vaccine: The label states it can be administered at any time relative to use of RELENZA. Can be administered at any time relative to RELENZA.
Read the label’s full interactions text
7 DRUG INTERACTIONS The concurrent use of RELENZA with 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 RELENZA, 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 RELENZA [see Microbiology ( 12.4 )] . Live attenuated influenza vaccine, intranasal ( 7 ): • Do not administer until 48 hours following cessation of RELENZA. • Do not administer RELENZA until 2 weeks following administration of the live attenuated influenza vaccine, unless medically indicated.
Not a complete list. The label covers the interactions the manufacturer studied or reported, and our own interaction database does not cover every medicine either. Bring your full medication list, including vitamins and herbal products, to your pharmacist.
Before taking Zanamivir Oral Inhalation
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- Do not use with a past allergic reaction to any ingredient, including milk proteins.
- Avoid with asthma, COPD or other airways disease unless your doctor decides the benefit outweighs the risk, with close monitoring.
- Children: young children may struggle to use the device.
- Older adults may need help with the device.
- Pregnancy: limited data have not shown increased risk.
- Breastfeeding: limited reports have not suggested a concern.
- Severe kidney disease: not studied, though no dose change is needed.
Zanamivir Oral Inhalation overdose
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Overdose reports have shown signs similar to normal doses and the flu itself. Zanamivir is expected to be removed by hemodialysis. Seek medical help if you take too much.
What Zanamivir Oral Inhalation does in the body
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In a heart rhythm study of healthy people, zanamivir given intravenously at far higher doses than Relenza did not affect the QTc interval or prolong the PR interval.
How your body processes Zanamivir Oral Inhalation
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Only about 4% to 17% of an inhaled dose is absorbed into the blood. Most of the dose lands in the mouth and throat, and about 13% reaches the lungs. Blood levels peak in 1 to 2 hours and the half-life is about 2.5 to 5 hours. No metabolites were found. Absorbed drug leaves through the kidneys, within 24 hours, and unabsorbed drug leaves in the stool.
How to store Zanamivir Oral Inhalation
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Store at 25 ° C (77 ° F); excursions permitted to 15 ° to 30 ° C (59 ° to 86 ° F) (see USP Controlled Room Temperature). Keep out of reach of children.
Written from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
Supplements & herbs that interact with Zanamivir Oral Inhalation
17 supplements and herbal products have documented interactions with Zanamivir Oral Inhalation in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.
- Major · 1
- Moderate · 7
- Minor · 9
Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.
Zanamivir Oral Inhalation: pharmacist answers to common questions
Quick, plain-English answers to the questions patients ask most about Zanamivir Oral Inhalation — the kind of thing our pharmacy team would talk through with you at the counter.
What is Relenza used for?
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How do I take it?
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Can I use it if I have asthma or COPD?
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What side effects should I expect?
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Does it affect vaccines?
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Is it safe in pregnancy?
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Is Zanamivir Oral Inhalation available over the counter?
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When was Zanamivir Oral Inhalation first available?
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Who makes Zanamivir Oral Inhalation?
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Answers drafted from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
More about Zanamivir Oral Inhalation on HelloPharmacist
Zanamivir Oral Inhalation forms and strengths (how it comes)
Zanamivir Oral Inhalation is available in 1 form. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Need a version that does not list lactose, a gluten source, a dye or gelatin? Inactive ingredients differ by manufacturer: see Zanamivir Oral Inhalation inactive ingredients by manufacturer.
Inhalation powder
How this form is used
- Relenza treats uncomplicated flu (types A and B) in people 7 years and older with symptoms for no more than 2 days.
- Relenza helps prevent flu in people 5 years and older.
- Relenza is for oral inhalation only, using the DISKHALER device provided.
- Relenza must not be made into a solution for a nebulizer or ventilator.
- If you use an inhaled bronchodilator, use it before Relenza.
- Relenza should be used by children only under adult supervision.
Zanamivir Oral Inhalation on the U.S. market: products, makers and brands
How Zanamivir Oral Inhalation appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
2 companies list 2 Zanamivir Oral Inhalation product records with the FDA, mostly as inhalation powder; the earliest marketing or approval year on record is 1999. Brand names on the directory include Relenza; the rest are generics.
Also listed with the FDA, not a patient dose form: Powder (1) — bulk drug substance sold to compounders/manufacturers and multi-item kits. These aren’t counted in the dose-form total above.
Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.
Compare Zanamivir Oral Inhalation products
A representative set of FDA-listed product records for Zanamivir Oral Inhalation — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Inhalation powder | ||||
| 5 mg | Respiratory (inhalation) | A-S Medication Solutions | NDA | View NDC → |
| 5 mg | Respiratory (inhalation) | GlaxoSmithKline LLC | NDA | View NDC → |
Showing 2 of 2 products — FDA National Drug Code Directory. See every product, package size and price: browse all 2 Zanamivir Oral Inhalation NDCs →
Zanamivir Oral Inhalation side effects reported to the FDA (FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Zanamivir Oral Inhalation — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Zanamivir Oral Inhalation in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
Zanamivir Oral Inhalation FDA approval history
How Zanamivir Oral Inhalation went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
Zanamivir Oral Inhalation recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
The FDA’s enforcement reports list no Zanamivir recalls since July 2021.
✅No Zanamivir recalls on record since July 2021Source: FDA enforcement (recall) reports, via openFDA; our copy was last updated Sep 24, 2026.
RxNorm Concept Web — From Ingredient to Every Form and Strength
This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.
RxCUI 69722 1 dose form · 1 strength
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Dose form (SCDF) Dry Powder Inhaler RxCUI 759470In current FDA listingsClinical drug / strength (SCD) 20 ACTUAT zanamivir 5 MG/ACTUATRxCUI 759471
Look up RxCUI 69722 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
Zanamivir Oral Inhalation supply and shortage status
Whether Zanamivir Oral Inhalation is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
💵 What Zanamivir Oral Inhalation costs pharmacies (NADAC benchmark)
The national average invoice price pharmacies pay for the drug itself, from CMS's NADAC survey (data as of Jan 14, 2026). This is a supply-cost benchmark — not a retail price and not what you'd pay at the counter.
| Form | Strength | Pharmacy acquisition benchmark | |
|---|---|---|---|
| Powder · Respiratory (inhalation) | 5 mg | $2.83 each | NDC details & price history |
Source: CMS National Average Drug Acquisition Cost (NADAC), a survey of retail pharmacy invoice prices. Benchmarks shown are the range across package sizes of a representative product for each form and strength — other manufacturers' products may differ.
Zanamivir Oral Inhalation brand names
Zanamivir Oral Inhalation is sold under one brand name in the FDA directory — Relenza. A brand and its generic contain the same active ingredient; the brand name belongs to one company's product.
Who makes Zanamivir Oral Inhalation: manufacturers and labelers
2 companies list Zanamivir Oral Inhalation products with the FDA. By number of product records, the largest are A-S Medication Solutions, GlaxoSmithKline LLC. Labelers include manufacturers and repackagers; the product in your bottle depends on which one your pharmacy stocks.
Zanamivir Oral Inhalation drug class (RxNorm)
Zanamivir Oral Inhalation belongs to the Neuraminidase Inhibitor class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
Sources for this Zanamivir Oral Inhalation page
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How this page is built
HelloPharmacist combines public FDA and NLM records and does not author the underlying clinical facts. The plain-language sections are written with AI from the FDA-approved label text and reviewed by our pharmacy team before publication. GlaxoSmithKline LLC is the representative DailyMed label linked for verification and dates. This is general education, not medical advice: always talk to your doctor or pharmacist about your own medicines. How we build and review drug pages →