Adult: For the treatment of acute, uncomplicated cases in patients who have been symptomatic for ≤48 hours and who are otherwise healthy or at high risk of developing influenza-related complications: Patients weighing 40-<80 kg: 40 mg; ≥80 kg: 80 mg. Doses must be taken as a single dose. Initiate treatment within 48 hours of the onset of symptoms. Dosing recommendations may vary among individual products and between countries (refer to specific product or local official guidelines). Child: ≥12 years Same as adult dose. Dosing recommendations may vary among individual products and between countries (refer to specific product or local official guidelines).
Oral Prophylaxis of influenza A and B
Adult: Postexposure prophylaxis after close contact with an infected individual: Patients weighing 40-<80 kg: 40 mg; ≥80 kg: 80 mg. Doses must be taken as a single dose. Initiate prophylaxis within 48 hours of exposure. Dosing recommendations may vary among individual products and between countries (refer to specific product or local official guidelines). Child: ≥12 years Same as adult dose. Dosing recommendations may vary among individual products and between countries (refer to specific product or local official guidelines).
What are the brands available for Baloxavir marboxil in Hong Kong?
Baloxavir marboxil May be taken with or without food. Do not take w/ dairy & polyvalent cation-containing products.
Reconstitution
Granules for oral susp: Reconstitute with 20 mL of sterile or drinking water to make a final concentration of 40 mg/20 mL (2 mg/mL). Gently swirl the bottle to suspend the granules evenly; do not shake.
Contraindications
Hypersensitivity.
Special Precautions
Patients with severe immunosuppression. Not to be used as a substitute for annual influenza vaccination. Concomitant use with live attenuated influenza vaccine (LAIV) has not been evaluated; avoid administration of LAIV within 2 weeks before or 48 hours after the administration of baloxavir marboxil. Children. Pregnancy and lactation.
Monitor for hypersensitivity reactions and potential secondary bacterial infections.
Drug Interactions
Reduced oral absorption and serum concentration with products containing polyvalent cations (e.g. Al, Ca, Mg, Fe, Zn, selenium); avoid coadministration with laxatives, oral supplements, antacids, or other preparations containing such cations. Baloxavir marboxil may inhibit the replication of live vaccine virus, which may reduce the efficacy of LAIV.
Food Interaction
Reduced oral absorption and serum concentration with products containing polyvalent cations (e.g. Al, Ca, Mg, Fe, Zn, selenium); avoid coadministration with dairy products and Ca-fortified beverages.
Action
Description: Mechanism of Action: Baloxavir marboxil is a prodrug of baloxavir, the active form that exhibits anti-influenza virus activity. Baloxavir selectively inhibits the cap-dependent endonuclease, an enzyme specific to the influenza virus found in the polymerase acidic (PA) subunit of the viral RNA polymerase complex, thereby preventing the transcription of influenza virus genomes and inhibiting viral replication. Pharmacokinetics: Absorption: Time to peak plasma concentration: 4 hours. Distribution: Volume of distribution: 1,180 L. Plasma protein binding: Approx 93-94%. Metabolism: Extensively and rapidly hydrolysed by esterases to form baloxavir, its active metabolite; baloxavir is then mainly metabolised by UGT1A3 and, to a minor extent, by CYP3A4. Excretion: Via faeces (80.1%); urine (14.7%; 3.3% as baloxavir). Elimination half-life: 79.1 hours.
Chemical Structure
Baloxavir marboxil Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 124081896, Baloxavir Marboxil. https://pubchem.ncbi.nlm.nih.gov/compound/Baloxavir-Marboxil. Accessed Mar. 26, 2025.
Storage
Tab/granules for oral susp: Store between 15-30°C. Keep the tab in the original container to protect from moisture. Reconstituted oral susp: Store between 20-25°C; discard if not used within 10 hours or stored >25°C.
J05AX25 - baloxavir marboxil ; Belongs to the class of other antivirals. Used as a direct acting antiviral in the systemic treatment of viral infections.
References
Baloxavir Marboxil. UpToDate Lexidrug, AHFS DI (Adult and Pediatric) Online. American Society of Health-System Pharmacists, Inc. Waltham, MA. UpToDate, Inc. https://online.lexi.com. Accessed 11/03/2025.Baloxavir Marboxil. UpToDate Lexidrug, Lexi-Drugs Multinational Online. Waltham, MA. UpToDate, Inc. https://online.lexi.com. Accessed 11/03/2025.Brayfield A, Cadart C (eds). Baloxavir Marboxil. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 11/03/2025.Joint Formulary Committee. Baloxavir Marboxil. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 11/03/2025.Xofluza 2 mg/mL Granules for Oral Suspension (Roche Products Limited). MHRA. https://products.mhra.gov.uk. Accessed 11/03/2025.Xofluza 20 mg Film-coated Tablets (Roche Products Limited). MHRA. https://products.mhra.gov.uk. Accessed 11/03/2025.Xofluza Film-coated Tablet 20 mg (Roche [Malaysia] Sdn. Bhd.). National Pharmaceutical Regulatory Agency - Ministry of Health Malaysia. https://www.npra.gov.my. Accessed 11/03/2025.Xofluza Tablet, Film Coated; Xofluza Granule, for Solution (Genentech, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 11/03/2025.
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