Patient Medication Information: uses, side effects, how to take - Arepanrix H5N1
What is AREPANRIXTM H5N1 used for?
AREPANRIX™ H5N1 influenza vaccine is indicated for active immunization against influenza caused by the H5N1 subtype virus contained in the vaccine. This indication is based on immunological data as the vaccine has not been evaluated in efficacy trials against influenza disease. AREPANRIX™ H5N1 should be used according to official guidance.
How does AREPANRIXTM H5N1 work?
When a person is given the vaccine, the immune system (the body’s natural defence system) will make antibodies against the H5N1 virus. These antibodies are expected to protect against disease caused by flu. None of the ingredients in the vaccine can cause influenza. There is no live virus in this vaccine.
As with all vaccines, AREPANRIX™ H5N1 may not fully protect all people who are vaccinated.
What are the ingredients in AREPANRIXTM H5N1?
Medicinal ingredients: H5N1 influenza antigen from A/American wigeon/South Carolina/22-000345-001/2021 (H5N1) strain and AS03 adjuvant.
The AS03 adjuvant in AREPANRIX™ H5N1 vaccine enhances the vaccine-induced immune response and contains naturally occurring molecules (squalene and vitamin E) plus an emulsifier (polysorbate 80).
Non-medicinal ingredients: Disodium hydrogen phosphate, Potassium chloride, Potassium dihydrogen phosphate, Sodium chloride, Thimerosal and Water for injection.
Thimerosal is a mercury derivative added as a preservative. Each adult dose contains 2.5 micrograms of mercury (1.25 micrograms of mercury for pediatric dose).
Trace amounts of egg proteins, formaldehyde, sodium deoxycholate and sucrose.
Serious Warnings and Precautions
Advise your healthcare professional immediately if you experience these reactions shortly after receiving your injection:
- Itchy skin rash
- Tightness in the throat, swelling of face or tongue
- Shortness of breath
AREPANRIXTM H5N1 comes in the following dosage forms:
AREPANRIX™ H5N1 is a two component vaccine consisting of a translucent to whitish opalescent suspension that may sediment slightly containing antigen and a whitish to yellowish homogeneous milky liquid emulsion containing the AS03 adjuvant. AREPANRIX™ H5N1 is an emulsion for injection.
Do not use AREPANRIXTM H5N1 if:
you have previously experienced a life-threatening allergic reaction to:
- egg proteins (egg or egg products) or chicken proteins
- other influenza vaccination
- any ingredient in the vaccine
Signs of an allergic reaction may include itchy skin rash, shortness of breath and swelling of the face or tongue.
To help avoid side effects and ensure proper use, talk to your healthcare professional before you receive AREPANRIXTM H5N1. Talk about any health conditions or problems you may have, including if you:
- have had any allergic reaction other than a sudden life-threatening allergic reaction to any ingredient contained in the vaccine.
- have a severe infection with a high temperature. In these cases, the vaccination may be postponed until recovery. A minor infection such as a cold should not be a problem, but talk to your doctor.
- have a weakened immune system due to medication or disease such as HIV. In such cases you may not get full benefit from the vaccination.
Other warnings you should know about:
Fainting can occur following, or even before any needle injection, therefore tell the healthcare professional if you fainted with a previous injection.
Tell your healthcare professional about all the medicines you take, including any drugs, vitamins, minerals, natural supplements or alternative medicines.
The following may interact with AREPANRIXTM H5N1:
There is currently no information on the administration of AREPANRIX™ H5N1 with other vaccines. AREPANRIX™ H5N1 should not be given at the same time as other vaccines. However, if this cannot be avoided, the other vaccine will be injected into the other arm. Any side effects that occur may be more severe.
How to take AREPANRIXTM H5N1:
Each dose is injected into your upper arm muscle or thigh.
Usual dose:
Adults 18 years of age and above should receive two doses (each 0.5 mL) of AREPANRIX™ H5N1 containing the A/American wigeon/South Carolina (H5N1) strain, the first administered at an elected date, the second at least three weeks after the first dose for maximum efficacy.
Children aged 6 months to 17 years should receive two doses (each 0.25 mL) of AREPANRIX™ H5N1 containing the A/American wigeon/South Carolina (H5N1) strain, the first administered at an elected date, the second at least three weeks after the first dose.
Use of the vaccine is not recommended in children aged less than 6 months.
Overdose:
If you think you, or a person you are caring for, have taken too much AREPANRIXTM H5N1, contact a healthcare professional, hospital emergency department, or regional poison control centre immediately, even if there are no symptoms.
What are possible side effects from using AREPANRIXTM H5N1?
As with all medicines, AREPANRIX™ H5N1 can cause side effects. The very common and common side effects are usually mild and should only last a day or two.
These are not all the possible side effects you may have when taking AREPANRIXTM H5N1. If you experience any side effects not listed here, tell your healthcare professional.
Very common (may occur with more than 1 in 10 doses):
- Pain at the injection site
- Headache
- Fatigue
- Aching muscles, joint pain
Common (may occur up to 1 in 10 doses)
- Redness or swelling at the injection site
- Fever
- Shivering
- Sweating
- Feeling sick
- Diarrhea
Uncommon (may occur with up to 1 in 100 doses)
- Reactions at the injection site such as bruising, hard lump, itching, warmth
- Swollen glands in neck
- Dizziness
- Generally feeling unwell
- Unusual weakness
- Vomiting, stomach pain, uncomfortable feeling in the stomach or belching after eating
- Inability to sleep
- Tingling or numbness of the hands or feet
- Shortness of breath
- Pain in the chest
- Itching, rash
- Pain in the back or neck, stiffness in the muscles, muscle spasms, pain in extremity such as leg or hand
In children 6 months to <6 years of age, the following additional side effects have been observed:
Very common (may occur with more than 1 in 10 doses):
- Loss of appetite
- Irritability
- Drowsiness
The following side effects were observed for other influenza vaccines containing AS03 adjuvant during the 2009 Influenza A (H1N1) pandemic.
- Allergic reaction leading to a dangerous decrease of blood pressure, which, if untreated, may lead to shock. Doctors are aware of this possibility and have emergency treatment available for use in such cases
- Inflammation at injection site
Swelling beneath the skin, giving rise to welts usually around
the eyes and lips but also on hands and feet
- Numbness and tingling sensation
- Neurological disorders such as convulsions, sleepiness and a type of paralysis know as Guillain-Barré Syndrome
The following additional side effects were observed for other marketed seasonal vaccines.
- Severe stabbing of throbbing pain along one or more nerves
- Low blood platelet count which can result in bleeding or bruising
- Vasculitis (inflammation of the blood vessels which can cause skin rashes, joint pain and kidney problems)
- Neurological disorders such as encephalomyelitis (inflammation of the central nervous system) and neuritis (inflammation of nerves)
If you have a troublesome symptom or side effect that is not listed here or becomes bad enough to interfere with your daily activities, tell your healthcare professional.
Reporting Suspected Side Effects for Vaccines
For the general public: Should you experience a side effect following immunization, please report it to your healthcare professional.
Should you require information related to the management of the side effect, please contact your healthcare professional. The Public Health Agency of Canada, Health Canada and GlaxoSmithKline Inc. cannot provide medical advice.
For healthcare professionals: If a patient experiences a side effect following immunization, please complete the Adverse Events Following Immunization (AEFI) Form appropriate for your province/territory (http://www.phac-aspc.gc.ca/im/aefi-essi-form-eng.php) and send it to your local Health Unit.
Storage:
Store in a refrigerator (2°C to 8°C) in the original package to protect from light.
Do not freeze.
Keep out of reach and sight of children.
If you want more information about AREPANRIXTM H5N1:
- Talk to your healthcare professional
- Find the full product monograph that is prepared for healthcare professionals and includes this Patient Medication Information by visiting the Health Canada website: (https://www.canada.ca/en/health-canada/services/drugs-health-products/drug-products/drug-product-database.html; the manufacturer’s website www.gsk.ca, or by calling 1-800-387-7374.
Last Revised January 26, 2026
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