Oseltamivir

Aka: Oseltamivir, Tamiflu, Neuraminidase Inhibitor

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II. Indications: Neuraminidase Inhibitor

  1. Neuraminidase Inhibitors covers both Influenza A and Influenza B
  2. Influenza
  3. Influenza prophylaxis

III. Precautions

  1. Influenza A (H1N1 Strain) was resistant to Oseltamivir in 2008 (Zanamivir was used)
  2. Symptom reduction is minimal (<14 to 16 hours) compared with those not treated
  3. Best efficacy if started within first 48 hours (although may still initiate later in high risk cases)
  4. Reserve use for those at highest risk of complications (although efficacy is limited even in high risk cases)
    1. Age under 2 years old or age over 65 years old
    2. Pregnancy
    3. Hospitalized patients
    4. Serious comorbidity

IV. Dosing

  1. Indicated for age 2 weeks and older (reduced from 1 year in U.S. as of 2013)
  2. Suspension may be compounded if not available
    1. Pharmacist can compound or
    2. Parents can mix contents of a Tamiflu capsule ort suspension with thick liquid (and give appropriate fraction of dose)
      1. Examples: Coffee Creamer, Chocolate syrup or similar
  3. Influenza Treatment
    1. Infants (approved for 2 weeks old and over)
      1. Dose: 3 mg/kg twice daily for 5 days
    2. Children
      1. Age <1 year: Dose: 3 mg/kg/dose up to 75 mg orally twice daily for 5 days
      2. Weight <15 kg: 30 mg orally twice daily for 5 days
      3. Weight 15 to 23 kg: 45 mg orally twice daily for 5 days
      4. Weight 23 to 40 kg: 60 mg orally twice daily for 5 days
    3. Teens and Adults
      1. Weight >40kg or Adult: 75 mg orally twice daily for 5 days
    4. Renal Dosing
      1. Creatinine Clearance 30 to 60 ml/min
        1. Dose 30 mg twice daily for 5 days
      2. Creatinine Clearance 10 to 30 ml/min
        1. Dose 30 mg once daily for 5 days
      3. Hemodialysis
        1. Dose 30 mg after Dialysis
  4. Influenza Prophylaxis
    1. Not routinely recommended due to medication shortage and resistance risk
      1. However, consider in high risk patients and their contacts (e.g. pregnancy, Immunocompromised)
      2. Postexposure Prophylaxis is very effective in preventing severe disease
        1. (2018) Pediatrics 142(4): e20182367 +PMID:30177511 [PubMed]
    2. Weight <15 kg (and age>=1 year): 30 mg orally daily for 7 to 10 days
    3. Weight 15 to 23 kg: 45 mg orally daily for 7 to 10 days
    4. Weight 23 to 40 kg: 60 mg orally daily for 7 to 10 days
    5. Weight >40kg or Adult: 75 mg orally daily for 7 to 10 days
    6. Advanced renal disease (Creatinine Clearance 10 to 30 ml/min)
      1. 75 mg every other day or 30 mg orally daily for 7-10 days
    7. Nursing Home
      1. Treat for at least 2 weeks and for at least 7 days after the last infected case in Nursing Home
      2. Isolate index patient to room and follow standard droplet precautions

V. Efficacy: Oseltamivir (Tamiflu)

  1. Reduces myalgias, fever and flu-like symptoms by 1 day (if started in first 48 hours)
    1. As of 2014, symptom reduction appears to be as little as <16 hours than if not treated
  2. Does NOT reduce Influenza complications (Pneumonia, mortality) including in the elderly and chronically ill
    1. Does NOT reduce the adult Influenza hospitalization rate (even in high risk patients)
    2. However is still recommended for high risk and hospitalized patients when started early
  3. References
    1. Jefferson (2012) Cochrane Database Syst Rev 1: CD008965 [PubMed]
    2. Hanula (2024) JAMA Intern Med 184(1): 18-27 [PubMed]

VI. Adverse effects

  1. Nausea and Vomiting
  2. Neuropsychiatric effects (e.g. Delirium)
  3. Stevens-Johnson Syndrome (rare)

VII. Safety

  1. Considered safe in Pregnancy (and recommended by CDC)
  2. Safe in Lactation

VIII. Drug Interactions

  1. Warfarin
    1. Monitor INR

IX. Resources

  1. Oseltamivir (DailyMed)
    1. https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=d306e22c-0cb8-46cb-9a40-8194a2bc9e85
  2. CDC InfluenzaAntivirals summary
    1. http://www.cdc.gov/flu/professionals/antivirals/summary-clinicians.htm

X. References

  1. (2014) Presc Lett 21(12): 70
  2. (2013) Med Lett Drugs Ther 11(127): 19-30 [PubMed]
  3. (2002) Pediatrics 110(6):1246-52 [PubMed]
  4. Stiver (2003) CMAJ 168(1):49-57 [PubMed]

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Related Studies

Cost: Medications

oseltamivir (on 12/28/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
OSELTAMIVIR 6 MG/ML SUSPENSION Generic $0.38 per ml
OSELTAMIVIR PHOS 30 MG CAPSULE Generic $1.27 each
OSELTAMIVIR PHOS 45 MG CAPSULE Generic $1.44 each
OSELTAMIVIR PHOS 75 MG CAPSULE Generic $1.49 each
tamiflu (on 2/23/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
TAMIFLU 6 MG/ML SUSPENSION Generic $0.38 per ml
TAMIFLU 75 MG CAPSULE Generic $1.49 each
FPNotebook does not benefit financially from showing this medication data or their pharmacy links. This information is provided only to help medical providers and their patients see relative costs. Insurance plans negotiate lower medication prices with suppliers. Prices shown here are out of pocket, non-negotiated rates. See Needy Meds for financial assistance information. GoodRx is another tool for finding lower drug prices.

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