Oseltamivir is used to treat and prevent influenza (also known as flu), an infection caused by a virus.
It is used to prevent flu in patients one year and older and treat uncomplicated acute (rapid onset/sudden) illness due to flu virus infection in patients more than 2 weeks of age who have shown symptoms for no more than 48 hours.
This medicine may also be used to prevent becoming infected with the flu virus after being potentially exposed it.
Take Oseltamivir exactly as directed by your doctor or according to the instructions on the label. Do not take more or less than instructed by your doctor.
You may take this medicine with or without food. Try to take it at the same time each day.
Oseltamivir is available as a capsule or powder for oral suspension.
If you are taking the capsule, swallow it whole with water. Do not chew or crush the capsule. If you have difficulty swallowing, capsule may be opened and mixed with sweetened food products such as chocolate syrup, sweetened condensed milk, apple sauce, or yogurt. A liquid suspension can also be made from the capsules if needed.
If you are taking the powder for oral suspension, shake the bottle well before you take it to ensure that the liquid is evenly mixed. Use the measuring spoon or cup provided to measure your prescribed dose. The dose of Oseltamivir will be decided by your doctor. Your doctor will advise you on the treatment regimen depending on your condition, response and tolerability to this medicine.
Oseltamivir must be used regularly for it to be effective. Continue taking this medicine even when you feel better. Do not stop using it unless instructed by the doctor. It is important to complete the entire course of medicine.
Take the missed dose as soon as you remember. If it is less than 2 hours before the next dose is due, skip the missed dose and return to your normal dosing schedule.
DO NOT double a dose under any circumstances.
If you often forget to take your medicine, let your doctor and pharmacist know.
Alert your doctor immediately if you are allergic to Oseltamivir and other similar medicines such as zanamivir.
Inform your doctor if you have the following conditions:
- chronic (long-lasting/persistent) heart disease
- severe kidney disease
- severe liver disease
- lung disease
- brain, spine, or nerve disease
- weak/impaired immune system
Oseltamivir is not a substitute for your yearly influenza vaccination.
Let your doctor know if you are pregnant or breastfeeding.
Inform your doctor if you have been recently vaccinated. Do not receive any vaccinations without first asking your doctor.
Keep your appointments with your doctor. Your doctor needs to monitor your condition and check your response to the medication regularly.
Oseltamivir may cause dizziness including vertigo (sensation that you or the environment around you, is moving or spinning). If affected, do not drive or take part in any activity in which you need to be alert.
Other side effects may include any of the following: headache, nausea, vomiting, pain, tiredness, fever, limb pain, stomach pain, indigestion, cough, sore throat, stuffy or runny nose, and difficulty sleeping.
Some side effects may need immediate medical help. Alert your doctor quickly if you experience any of the following:
- swelling of the mouth, face, lips, tongue, or throat
- skin rashes leading to blisters, peeling, and shedding of large skin areas
- unusual changes in mood or behaviour (being too depressed, agitated, or having compulsive and impulsive behaviour)
- confusion, hallucinations (seeing or hearing things that are non-existent), thoughts of self-harm
Inform your doctor if any of these side effects do not go away or are severe, or if you experience other side effects.
Inform your doctor and pharmacist if you are taking any of these medicines:
- medicine for diabetes e.g. chlorpropamide
- medicine to treat rheumatoid arthritis e.g. methotrexate
- medicine for gout e.g. probenecid
- NSAIDs (medicine for pain and inflammation) e.g. phenylbutazone
This list does not include all medicines that may interact with Oseltamivir.
Always notify your doctor and pharmacist if you are taking any other medicines, including herbal tonics such as traditional Chinese medicines, supplements and medicines that you buy without a prescription.
Store capsules and powder for oral suspension in a cool, dry place away from the reach of children.
Once you have mixed the powder with water, the oral suspension can be stored at room temperature not more than 25°C. Throw away any unused portion after 10 days.
The oral suspension may also be stored in the refrigerator (between 2-8°C). Do not freeze it otherwise it will become less effective. Throw away any unused portion after 17 days.
Medicines must not be used past the expiry date.
Do not throw it away in the household waste. Ask your doctor or pharmacist how to throw away expired medicines or medicines you no longer use.