Continue to Save Flu Antivirals for High-Risk Patients

Concerns about a severe flu season will put focus on when to use an antiviral to treat or prevent influenza.

The southern hemisphere had its worst flu season in years...and this often forecasts what will happen north of the equator.

If COVID-19 cases also surge, a “twindemic” is possible.

Test all symptomatic patients for COVID-19. Find out when to use a COVID-19 antiviral in our resource, Outpatient COVID-19 Treatment Options.

Also test for flu if you’d consider treating it...such as patients at high risk of complications (age over 65, diabetes, etc). These patients are most likely to benefit from a flu antiviral.

Treatment. Don’t feel compelled to use an antiviral to treat flu in most healthy patients. Advise fluids, rest, etc.

Oseltamivir (Tamiflu) or baloxavir (Xofluza) only reduces flu symptoms by about a day...if started within 48 hours of symptom onset.

For now, stick with oseltamivir for hospitalized patients...severely ill patients (pneumonia, asthma or COPD exacerbation, etc)...and most high-risk outpatients (immunocompromised, pregnant, etc). Evidence is lacking with baloxavir in these situations.

Consider baloxavir or oseltamivir for NONsevere flu in other outpatients with risks (diabetes, heart disease, etc). Data suggest baloxavir works as well as oseltamivir in these cases.

Plus baloxavir is one dose...causes less GI upset than oseltamivir...and is now approved down to age 5. But baloxavir tabs cost about $150/dose...oseltamivir caps are $25 for 5 days.

Avoid combining oseltamivir with baloxavir...this doesn’t seem beneficial. It’s okay to combine antivirals to treat COVID-19 and flu.

Prevention. Don’t routinely use any antiviral for flu postexposure prophylaxis...to limit resistance, shortages, and side effects.

Generally save prophylaxis for institutional outbreaks...or for exposed patients who are immunocompromised.

Either baloxavir or oseltamivir is effective...but oseltamivir has a longer track record.

Emphasize flu vaccines, handwashing, staying home if sick, etc.

Compare other antivirals (Relenza, etc) for flu treatment and prevention in our resource, Antivirals for Influenza.

Key References

  • https://www.cdc.gov/flu/professionals/antivirals/summary-clinicians.htm (10-22-22)
  • Clin Infect Dis. 2019 Mar 5;68(6):895-902
  • https://www.cdc.gov/flu/professionals/diagnosis/testing-guidance-for-clinicians.htm (10-22-22)
  • Lancet Infect Dis. 2022 May;22(5):718-730
  • Medication pricing by Elsevier, accessed Oct 2022
Prescriber's Letter. November 2022, No. 381102



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