Oseflu

Indications

Oseltamivir is an antiviral medicine used to treat influenza (flu) caused by influenza A and B viruses in adults and children, and to prevent flu in people who have been in close contact with someone who has it. It does not work against the common cold, COVID-19 or bacterial infections, and it does not replace the yearly flu vaccine.

How It Works

It blocks a viral enzyme called neuraminidase, which the flu virus needs to escape from infected cells and spread. This shortens the illness and lowers the risk of complications. It works best when started within 48 hours of the first flu symptoms.

Dosage and Administration

Adults and children 13 years and older (or over 40 kg): treatment, 75 mg twice a day for 5 days; prevention after contact, 75 mg once a day for at least 10 days, or as the doctor advises. Children under 13 and infants: the dose depends on body weight and is given as prescribed, usually as the oral suspension. People with kidney problems need a lower dose. Take with food to reduce stomach upset, and complete the full course.

Interactions

• Live nasal flu vaccine: do not take oseltamivir from 2 days before to 2 weeks after this vaccine, as it may stop the vaccine working. Injected flu vaccines are not affected.
• Probenecid increases oseltamivir levels; a dose change is rarely needed.
• Few other interactions are known; tell the doctor about all medicines you take.

Contraindications

Allergy to oseltamivir or any ingredient of the product.

Side Effects

Common effects are nausea, vomiting, stomach pain and headache, usually mild and mostly in the first 2 days. Less often there may be diarrhoea, dizziness, cough or tiredness. Rarely, sudden confusion, unusual behaviour or hallucinations have been reported, mainly in children and teenagers, although flu itself can also cause these.

Get urgent medical help for signs of a serious allergic reaction (swelling of the face or throat, difficulty breathing), a blistering or peeling rash, or unusual behaviour. Also seek urgent care if the flu gets worse: difficulty breathing, chest pain, bluish lips, confusion, fits, or a high fever that does not settle.

Pregnancy and Lactation

Pregnant women are at higher risk of severe flu, and oseltamivir is commonly used in pregnancy when a doctor advises it. It passes into breast milk only in small amounts and breastfeeding can usually continue.

Precautions and Warnings

• Start as soon as possible after symptoms begin.
• Tell the doctor about kidney disease; the dose may need to be lowered.
• Watch children and teenagers for unusual behaviour during the illness.
• The suspension may contain sorbitol; people with hereditary fructose intolerance should tell the doctor.
• Keep up with yearly flu vaccination.

Overdose

Overdose most often causes nausea, vomiting and dizziness. Seek medical advice, especially if a child has taken too much.

Therapeutic Class

Antiviral medicine (neuraminidase inhibitor).

Storage

Store capsules and dry powder below 30°C in a dry place, away from light and out of the reach of children. After the suspension is mixed, store it as stated on the pack (often in a fridge at 2 to 8°C) and throw away any left after the stated number of days.