From the Guidelines
Tamiflu (oseltamivir) is typically prescribed for a 5-day course for both treatment and prevention of influenza. The recommended duration of treatment with oseltamivir is 5 days, as stated in the study published in 2008 1. This recommendation is consistent with more recent guidelines, such as those published in 2021 1, which also recommend a 5-day course of oseltamivir for treatment of influenza.
Key Points
- The standard adult dose of oseltamivir is 75 mg twice daily for treatment, and 75 mg once daily for prevention after exposure to influenza.
- Children's dosing varies based on weight, with different dosages recommended for different age groups and weights.
- Oseltamivir works by inhibiting the viral neuraminidase enzyme, preventing new virus particles from being released from infected cells.
- It can reduce the duration of flu symptoms by about 1-2 days and may decrease the severity of symptoms, but it is not a substitute for the flu vaccine.
- If prescribed Tamiflu, it is essential to complete the entire course, even if symptoms improve before finishing the medication.
Dosage Information
- For adults, the recommended dose is 75 mg twice daily for 5 days for treatment, and 75 mg once daily for 10 days for prevention.
- For children, the dosage varies based on weight, with the following recommendations:
- For children 12 months and older, the dosage is based on body weight, with 30 mg twice daily for children weighing less than 15 kg, 45 mg twice daily for children weighing 15-23 kg, 60 mg twice daily for children weighing 23-40 kg, and 75 mg twice daily for children weighing more than 40 kg.
- For infants 9-11 months, the recommended dose is 3.5 mg/kg per dose, twice daily.
- For term infants 0-8 months, the recommended dose is 3 mg/kg per dose, twice daily.
Important Considerations
- Oseltamivir is not a substitute for the flu vaccine, and vaccination is still the best way to prevent influenza.
- Oseltamivir can cause side effects, such as nausea and vomiting, which can be reduced by taking the medication with food.
- It is essential to follow the recommended dosage and duration of treatment to ensure effective treatment and minimize the risk of resistance.
From the FDA Drug Label
3-day reduction in the median time to improvement in influenza-infected subjects who received oseltamivir phosphate 75 mg twice a day for 5 days Oseltamivir phosphate treatment of 2 mg per kg twice daily, started within 48 hours of onset of symptoms, reduced the total composite time to freedom from illness by 1. 5 days compared to placebo. Subjects received oseltamivir phosphate at doses ranging from 2 to 3. 5 mg per kg twice daily for 5 days Oseltamivir phosphate 75 mg once daily taken for 42 days during a community outbreak Oseltamivir phosphate 75 mg once daily or placebo taken orally for 7 days
The standard treatment duration for Tamiflu is 5 days for treatment of influenza, and 7 to 42 days for prophylaxis of influenza, depending on the specific situation, as indicated in the FDA drug label 2.
From the Research
Duration of Tamiflu Treatment
- The duration of Tamiflu treatment is not explicitly stated in the provided studies, but the effectiveness of oseltamivir (Tamiflu) in treating influenza is discussed in several studies 3, 4, 5, 6, 7.
- A study from 2018 found that the duration of fever after administration of the first dose of oseltamivir was shorter in older patients and in patients with influenza A infection than in patients with influenza B infection 3.
- Another study from 2011 reported that the incidence of oseltamivir resistance was 2.6% and that oseltamivir resistance was significantly associated with pneumonia 4.
- A 2013 review of influenza antivirals discussed the pharmacokinetics and clinical data available for oseltamivir, but did not provide information on the duration of treatment 5.
- A 2022 study compared the effectiveness of inhaled zanamivir and oral oseltamivir in preventing influenza-related hospitalization or death, but did not report on the duration of treatment 6.
- A 2012 study evaluated the clinical effectiveness of oseltamivir, zanamivir, laninamivir, and peramivir in treating influenza A(H3N2) and A(H1N1)pdm09 infection, and found that peramivir had the fastest time to fever alleviation, but did not provide information on the duration of treatment 7.