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Baloxavir Marboxil

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Baloxavir Marboxil, Xofluza

  • See Also
  1. Influenza
  • Indications
  1. Influenza (A or B)
    1. Alternative to Oseltamivir (Tamiflu) in non-severe Influenza
    2. Indicated in Non-hospitalized patients with risk factors (e.g. diabetes, heart disease)
      1. Age >= 5 years old and symptoms <=48 hours
      2. Oseltamivir is recommended instead in severe cases
  • Mechanism
  1. Cap-dependent endonuclease inhibitor
  2. Some RNA Viruses (including Influenza) replicate via cap snatching
    1. Virus extracts first 15-20 of host RNA residues which is used as 5' cap on virus RNA
    2. Virus RNA Polymerase has endonuclease functionality used in cap snatching
  • Dosing
  1. Costs $150 in 2022 (contrast with $25 to $40 for 5 days of Tamiflu)
  2. One single oral dose for over age 12 years
    1. Weight 88 to 176 lb (40 to 80 kg)
      1. Give 40 mg (two 20 mg tablets)
    2. Weight >176 lb (>80 kg)
      1. Give 80 mg (two 40 mg tablets)
  • Efficacy
  1. May shorten Influenza symptoms by up to 1 day if started within 48 hours (similar to Oseltamivir)
  2. No evidence for benefit in high risk patients (under age 2, over age 65, pregnancy) to prevent complications
  3. Appears effective for Influenza Prophlaxis (but not FDA approved for prophylaxis as of 2020)
    1. Single dose after household exposure may prevent up to 1 case in 9 contacts
    2. Ikematsu (2020) N Engl J Med 383:309-20 [PubMed]
  • Adverse Effects (in 1-3% of patients)
  1. Diarrhea
  2. Nausea
  3. Bronchitis
  4. Headache
  • Drug Interactions
  1. Agents that decrease absorption (e.g. Calcium including dairy products, aluminum, Magnesium or iron salts)
  • Resources
  1. Baloxavir Marboxil (DailyMed)
    1. https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=e49e1a61-1b7c-4be5-ac84-af6240b511e7
  • References
  1. (2023) Presc Lett 30(11): 62-3
  2. (2020) Presc Lett 27(10): 55-6
  3. (2018) Presc Lett 25(12): 67
  4. Erlich (2019) Am Fam Physician 100(12): 776-7 [PubMed]