II. Indications: Neuraminidase Inhibitor
III. Precautions
- Influenza A (H1N1 Strain) was resistant to Oseltamivir in 2008 (Zanamivir was used)
- Symptom reduction is minimal (<14 to 16 hours) compared with those not treated
- Best efficacy if started within first 48 hours (although may still initiate later in high risk cases)
- Reserve use for those at highest risk of complications (although efficacy is limited even in high risk cases)
- Age under 2 years old or age over 65 years old
- Pregnancy
- Hospitalized patients
- Serious comorbidity
IV. Dosing
- Indicated for age 2 weeks and older (reduced from 1 year in U.S. as of 2013)
- Suspension may be compounded if not available
- Pharmacist can compound or
- Parents can mix contents of a Tamiflu capsule ort suspension with thick liquid (and give appropriate fraction of dose)
- Examples: Coffee Creamer, Chocolate syrup or similar
-
Influenza Treatment
- Infants (approved for 2 weeks old and over)
- Dose: 3 mg/kg twice daily for 5 days
- Children
- Age <1 year: Dose: 3 mg/kg/dose up to 75 mg orally twice daily for 5 days
- Weight <15 kg: 30 mg orally twice daily for 5 days
- Weight 15 to 23 kg: 45 mg orally twice daily for 5 days
- Weight 23 to 40 kg: 60 mg orally twice daily for 5 days
- Teens and Adults
- Weight >40kg or Adult: 75 mg orally twice daily for 5 days
- Renal Dosing
- Creatinine Clearance 30 to 60 ml/min
- Dose 30 mg twice daily for 5 days
- Creatinine Clearance 10 to 30 ml/min
- Dose 30 mg once daily for 5 days
- Hemodialysis
- Dose 30 mg after Dialysis
- Creatinine Clearance 30 to 60 ml/min
- Infants (approved for 2 weeks old and over)
-
Influenza Prophylaxis
- Not routinely recommended due to medication shortage and resistance risk
- However, consider in high risk patients and their contacts (e.g. pregnancy, Immunocompromised)
- Postexposure Prophylaxis is very effective in preventing severe disease
- Weight <15 kg (and age>=1 year): 30 mg orally daily for 7 to 10 days
- Weight 15 to 23 kg: 45 mg orally daily for 7 to 10 days
- Weight 23 to 40 kg: 60 mg orally daily for 7 to 10 days
- Weight >40kg or Adult: 75 mg orally daily for 7 to 10 days
- Advanced renal disease (Creatinine Clearance 10 to 30 ml/min)
- 75 mg every other day or 30 mg orally daily for 7-10 days
- Nursing Home
- Treat for at least 2 weeks and for at least 7 days after the last infected case in Nursing Home
- Isolate index patient to room and follow standard droplet precautions
- Not routinely recommended due to medication shortage and resistance risk
V. Efficacy: Oseltamivir (Tamiflu)
- Reduces myalgias, fever and flu-like symptoms by 1 day (if started in first 48 hours)
- As of 2014, symptom reduction appears to be as little as <16 hours than if not treated
- Does NOT reduce Influenza complications (Pneumonia, mortality) including in the elderly and chronically ill
- Does NOT reduce the adult Influenza hospitalization rate (even in high risk patients)
- However is still recommended for high risk and hospitalized patients when started early
- References
VI. Adverse effects
- Nausea and Vomiting
- Neuropsychiatric effects (e.g. Delirium)
- Stevens-Johnson Syndrome (rare)
VII. Safety
- Considered safe in Pregnancy (and recommended by CDC)
- Safe in Lactation
VIII. Drug Interactions
-
Warfarin
- Monitor INR
IX. Resources
X. References
Images: Related links to external sites (from Bing)
Related Studies
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 |
Ontology: Oseltamivir (C0874161)
Definition (NCI) | A synthetic derivative prodrug of ethyl ester with antiviral activity. Osetamivir blocks neuraminidases on the surfaces of influenza viruses, interfering with host cell release of complete viral particles. |
Definition (MSH) | An acetamido cyclohexene that is a structural homolog of SIALIC ACID and inhibits NEURAMINIDASE. |
Concepts | Pharmacologic Substance (T121) , Organic Chemical (T109) |
MSH | D053139 |
SnomedCT | 386142008, 412261005 |
LNC | LP101308-7, MTHU036068 |
English | ethyl (3R,4R,5S)-4-acetamido-5-amino-3-pentan-3-yloxy-cyclohexene-1-carboxylate, Oseltamivir [Chemical/Ingredient], OSELTAMIVIR, oseltamivir, Oseltamivir, Oseltamivir (product), Oseltamivir (substance) |
Portuguese | Oseltamivir |
Spanish | Oseltamivir, oseltamivir (producto), oseltamivir, oseltamivir (sustancia) |
Russian | ТАМИФЛУ, ОЗЕЛТАМИВИР, GS 4071, ТАМИФЛЮ, TAMIFLU, OZELTAMIVIR, TAMIFLIU |
Italian | Oseltamivir |
German | Oseltamivir |
Finnish | Oseltamiviiri |
Czech | oseltamivir |
Japanese | オセルタミビル |
Swedish | Oseltamivir |
French | Oséltamivir |
Polish | Oseltamiwir |
Ontology: Tamiflu (C0876173)
Concepts | Pharmacologic Substance (T121) , Organic Chemical (T109) |
MSH | D053139 |
English | Tamiflu, oseltamivir phosphate (Tamiflu), tamiflu |
French | Tamiflu |
German | Tamiflu |
Italian | Tamiflu |
Czech | Tamiflu |
Ontology: Neuraminidase inhibitor (C1443650)
Concepts | Pharmacologic Substance (T121) |
SnomedCT | 409228005, 409227000 |
English | Sialidase inhibitor, Neuraminidase inhibitor, Neuraminidase inhibitor (product), Neuraminidase inhibitor (substance) |
Spanish | inhibidor de la neuraminidasa (producto), inhibidor de la neuraminidasa (sustancia), inhibidor de la neuraminidasa |