Xofluza Dosing
Xofluza (baloxavir marboxil) is administered as a single oral dose based on body weight: 40 mg for patients weighing 20 kg to less than 80 kg, and 80 mg for patients weighing at least 80 kg, taken as soon as possible within 48 hours of symptom onset for treatment or following exposure for prophylaxis. 1
Dosing by Body Weight
Adults and Pediatric Patients ≥5 Years of Age
- 20 kg to <80 kg: Single 40 mg dose 1
- ≥80 kg: Single 80 mg dose 1
- 15 kg to <20 kg: Single 30 mg dose (oral suspension packet) 1
- <15 kg: 2 mg/kg as oral suspension from bottle 1
Timing of Administration
- Treatment: Administer within 48 hours of influenza symptom onset 1
- Post-exposure prophylaxis: Administer following contact with an individual who has influenza 1
Formulation Options
Xofluza is available in three presentations to accommodate different patient needs 1:
- Tablets: 40 mg and 80 mg tablets for patients who can swallow pills 1
- Oral suspension packets: 30 mg and 40 mg packets for patients unable to swallow tablets 1
- Oral suspension bottles: 2 mg/mL concentration, recommended for patients weighing less than 15 kg or requiring enteral administration 1
Critical Administration Requirements
Avoid concomitant use with dairy products, calcium-fortified beverages, polyvalent cation-containing laxatives, antacids, or oral supplements containing calcium, iron, magnesium, selenium, or zinc, as these significantly reduce antiviral efficacy. 1, 2
- Xofluza may be taken with or without food 1
- The single-dose regimen offers a practical advantage over multi-day neuraminidase inhibitor regimens 3
Mechanism and Clinical Context
Baloxavir marboxil is a first-in-class cap-dependent endonuclease inhibitor that blocks influenza virus replication by inhibiting mRNA synthesis 3, 4. It demonstrates activity against influenza A and B viruses, including strains resistant to neuraminidase inhibitors 3. Evidence shows baloxavir reduces viral load more rapidly than oseltamivir while displaying similar efficacy in symptom improvement 3.
Common Pitfall
The most critical error to avoid is administering Xofluza with calcium, aluminum, or magnesium-containing products, which leads to loss of antiviral efficacy 2. Patients should be explicitly counseled to separate these products from Xofluza administration.