Oseltamivir Capsule: Uses, Dosage, Side Effects, Precautions and Alternates

Quick overview

Oseltamivir Capsule (generic name: oseltamivir phosphate) is a prescription antiviral medicine from the neuraminidase inhibitor class. It is used to treat and prevent influenza (flu) caused by influenza A and B viruses, but it does not treat colds or illnesses not caused by the flu virus. It works by blocking an enzyme the influenza virus needs to spread inside the body.

What is Oseltamivir Capsule

Oseltamivir is a prescription antiviral medicine used to treat and prevent influenza (flu) caused by influenza A and B viruses. It does not treat colds or other illnesses not caused by the flu virus.

Oseltamivir Capsule uses

• Treatment of the flu in people 2 weeks of age and older who have had flu symptoms for no more than 2 days
• Prevention of the flu in people 1 year of age and older who may have been exposed to someone with the flu

Benefits of Oseltamivir Capsule

• May help you feel better faster if you already have the flu
• Can help prevent you from catching the flu after exposure
• Helps reduce the chance of passing the flu to someone else
• May lower the chance of developing flu complications such as bronchitis, pneumonia and sinusitis

How Oseltamivir Capsule works

Oseltamivir works by blocking an enzyme the influenza virus needs to spread inside the body, which stops the virus from releasing new viral particles and spreading further.

Oseltamivir Capsule dosage

Take the capsule exactly as your healthcare provider tells you to. Swallow the capsule whole with a full glass of water; do not break or chew it before swallowing. It may be taken with or without food, but taking it with food can lessen the chance of stomach upset.

Start treatment as soon as possible after flu symptoms appear, within 48 hours of symptom onset. For treatment, doses are usually spaced 12 hours apart for 5 days. For prevention, doses are usually taken once every 24 hours for 10 days, or as prescribed.

If you cannot swallow the capsule, your healthcare provider or pharmacist may tell you to open it and mix the contents with a sweetened liquid such as chocolate syrup, corn syrup, caramel topping, or light brown sugar dissolved in water.

If you miss a dose, take it as soon as you remember, unless it is within 2 hours of your next dose — in that case skip the missed dose and continue your regular schedule; do not take two doses at once. Continue taking the medicine for the full prescribed length of time, even if you start to feel better. Use in elderly patients follows the same dosing recommendations as for other adults.

Available forms and strengths

• Capsules (30 mg, 45 mg, 75 mg)
• Powder for oral suspension

Side effects of Oseltamivir Capsule

Common

• Nausea
• Vomiting
• Headache
• Pain (when used for prevention)
• Stomach ache, indigestion
• Diarrhoea
• Dizziness/vertigo
• Insomnia
• Cough
• Fatigue
• Aches and pains
• Mild skin rash

Serious

• Serious skin and allergic reactions including rash or hives, skin blistering and peeling, swelling of face, eyes, lips, tongue, or throat, trouble breathing, blisters or sores in the mouth, chest pain or tightness, itching
• Change in behavior, especially in children, including confusion, speech problems, shaky movements, seizures, hallucinations
• Toxic epidermal necrolysis, Stevens-Johnson Syndrome, erythema multiforme
• Anaphylaxis
• Gastrointestinal bleeding, hemorrhagic colitis
• Arrhythmia
• Hepatitis, abnormal liver function tests
• Seizure
• Aggravation of diabetes
• Delirium, agitation, anxiety, altered level of consciousness, nightmares, delusions

Warnings and precautions

• Oseltamivir can cause serious skin and allergic reactions, including severe allergic reactions like anaphylaxis and serious skin reactions. Stop taking the medicine and get medical help right away if these occur.
• People with the flu, especially children, can develop nervous system problems and abnormal behavior that can lead to death, whether or not they are taking this medicine.
• This medicine does not replace an annual flu vaccination. Continue to get vaccinated as recommended.
• Avoid the nasal spray flu vaccine within 2 weeks before or 48 hours after taking this medicine, since it can make the vaccine less effective.
• This medicine does not treat infections other than influenza and does not prevent bacterial infections that can occur along with the flu.
• It is dangerous to buy this medicine online or from outside the country, as such products may contain unsafe ingredients or not be from a licensed pharmacy.
• There is limited data on the safety of oseltamivir in pregnancy, but available information suggests it does not increase the risk of birth defects. Your doctor will weigh the risks and benefits if you are pregnant, since flu itself can cause serious complications during pregnancy.
• Oseltamivir can pass into breast milk in small amounts. Tell your doctor if you are breastfeeding so they can weigh the benefits and risks.
• People with kidney problems may need a lower dose. Oseltamivir is not recommended for people with end-stage kidney disease who are not on dialysis. Tell your doctor if you have kidney disease or are on dialysis.
• No dose adjustment is needed for people with mild to moderate liver problems. The safety of oseltamivir has not been studied in people with severe liver impairment.
• Be careful when driving or using machinery until you know how this medicine affects you, although it is not expected to affect your ability to drive or operate machines.

Storage

• Store at room temperature between 68°F to 77°F (20°C to 25°C)
• Safely throw away any unused capsules that are out of date or no longer needed
• Keep out of the reach of children
• Keep capsules in the blister pack until it is time to take them
• Store in a cool, dry place away from moisture, heat, or sunlight

When to see a doctor

• Stop taking the medicine and get medical help right away if you notice skin rash or hives, swelling of the face, eyes, lips, tongue, or throat, skin blistering or peeling, trouble breathing, mouth blisters or sores, chest pain or tightness, or itching.
• Tell your healthcare provider right away if you or your child show confusion, speech problems, shaky movements, seizures, or hallucinations (hearing voices or seeing things that are not there) during treatment.
• Get urgent medical attention if you think you have taken too much of this medicine.
• Call your doctor right away if your flu symptoms get worse after starting this medicine.

Alternatives

• Tamiflu
• Zanamivir
• Baloxavir marboxil