Xofluza

What is Xofluza?

Xofluza is a prescription-only medicine in Hong Kong that is widely used for patients presenting with acute uncomplicated influenza.

Unlike neuraminidase inhibitors such as oseltamivir, Xofluza belongs to a class of cap-dependent endonuclease inhibitors that work by stopping the viral replication process within the body.

Generic Names:

• Baloxavir marboxil: The universally recognised generic name for the active pharmaceutical ingredient, widely utilised in clinical settings globally.

Global Brand Names:

• Xofluza: This is the primary brand name used internationally, including in Hong Kong, for both adult and paediatric formulations.

What is Xofluza used for?

Xofluza is used to relieve:

• Symptoms associated with acute uncomplicated influenza in otherwise healthy patients, or those at high risk of complications, who have exhibited symptoms for no more than 48 hours.
• The risk of developing symptoms following exposure to an infected individual (post-exposure prophylaxis for patients aged 5 years or above).

How do you use Xofluza?

Availability:

• Oral tablets (Currently the only registered form in Hong Kong).
• Oral suspension.

Suitability:

• Adults: Yes, suitable for general adult use.
• Elderly: Yes, no dose adjustment is required.
• Children: Yes, for those aged 5 years or older.
• Pregnant Women: No, adequate data regarding developmental risks is unavailable.
• Lactating Women: No, due to a lack of data on milk presence and effects on infants.

Dosage Information:

• Patients weighing 20 to <80 kg: 40 mg as a single oral dose.
• Patients weighing 80 kg or more: 80 mg as a single oral dose.

Who cannot take Xofluza?

• Children under 5 years of age.
• Individuals with severe renal impairment.
• Individuals with severe hepatic impairment.

Allergies and unsuitability:

• Rare, but possible severe allergic reactions including anaphylaxis, angioedema, urticaria, and erythema multiforme.

Warnings and precautions:

• Do not rely on this medication for bacterial infections; there is a risk of untreated bacterial complications.
• Monitor for treatment-emergent viral resistance, particularly in younger patients.

Interactions and contraindications:

• Avoid taking with dairy products to maintain drug absorption.
• Avoid coadministration with calcium-fortified beverages or supplements containing polyvalent cations (such as calcium, magnesium, iron, zinc, or selenium) as they can interfere with efficacy.
• Avoid concurrent use with live attenuated influenza vaccine (LAIV) to prevent a decrease in the vaccine's effectiveness.

Conditions where the drug should not be used:

• Known hypersensitivity to baloxavir marboxil.
• Severe renal impairments.
• Severe hepatic impairments.

Common side effects differ slightly by age group. Adults and adolescents may experience diarrhoea, bronchitis, nausea, sinusitis, and headache. Paediatric patients aged 5 to under 12 frequently report vomiting and diarrhoea.

Severe adverse reactions require immediate medical attention. These include serious allergic responses such as difficulty breathing, skin rashes, hives, swelling of the face, throat or mouth, and severe dizziness or lightheadedness. Never exceed the single prescribed dose, as misuse may increase the risk of adverse events.

Warnings and precautions:

• Do not rely on this medication for bacterial infections; there is a risk of untreated bacterial complications.
• Monitor for treatment-emergent viral resistance, particularly in younger patients.

Interactions and contraindications:

• Avoid taking with dairy products to maintain drug absorption.
• Avoid coadministration with calcium-fortified beverages or supplements containing polyvalent cations (such as calcium, magnesium, iron, zinc, or selenium) as they can interfere with efficacy.
• Avoid concurrent use with live attenuated influenza vaccine (LAIV) to prevent a decrease in the vaccine's effectiveness.

Conditions where the drug should not be used:

• Known hypersensitivity to baloxavir marboxil.
• Severe renal impairments.
• Severe hepatic impairments.

Storage information:

• Keep tablets in their original blister package at room temperature.
• Store in a dry place out of reach of children.

Handling instructions:

• Swallow the tablet whole with a glass of water.
• Take the medication as a single dose exactly as prescribed based on your body weight.

Where is Xofluza available in Hong Kong?

Xofluza is classified as a "Prescription Only Medicine" in Hong Kong. Patients must present a valid doctor's prescription to purchase it at a registered pharmacy.

It can be legally obtained at registered dispensaries displaying the "Rx" logo or through hospital and clinic pharmacies directly from a healthcare provider.