What is the effective dosage of Tamiflu (Oseltamivir) pills?

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Last updated: February 17, 2025View editorial policy

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From the Guidelines

The effective dosage of Tamiflu (Oseltamivir) pills for the treatment of influenza is 75mg twice daily for 5 days 1. For prophylaxis, the recommended dosage is 75mg once daily for at least 7 days 1.

Dosage by Age and Weight

  • For adults, the dosage is 75mg twice daily for 5 days for treatment and 75mg once daily for 10 days for chemoprophylaxis 1.
  • For children over 12 months, the dosage varies by weight:
    • 15 kg (33 lb) or less: 30 mg twice daily for treatment and 30 mg once daily for chemoprophylaxis 1.
    • 15-23 kg (33-51 lb): 45 mg twice daily for treatment and 45 mg once daily for chemoprophylaxis 1.
    • 23-40 kg (51-88 lb): 60 mg twice daily for treatment and 60 mg once daily for chemoprophylaxis 1.
    • over 40 kg (88 lb): 75 mg twice daily for treatment and 75 mg once daily for chemoprophylaxis 1.
  • For infants 9-11 months, the dosage is 3.5 mg/kg per dose twice daily for treatment and 3.5 mg/kg per dose once daily for chemoprophylaxis 1.
  • For term infants 0-8 months, the dosage is 3 mg/kg per dose twice daily for treatment and 3 mg/kg per dose once daily for chemoprophylaxis 1.
  • For preterm infants, the dosage varies by postmenstrual age:
    • less than 38 weeks: 1.0 mg/kg per dose twice daily 1.
    • 38-40 weeks: 1.5 mg/kg per dose twice daily 1.
    • over 40 weeks: 3.0 mg/kg per dose twice daily 1. It is essential to note that these dosages are based on the most recent guidelines and may be subject to change as new evidence emerges 1.

From the FDA Drug Label

2.2 Recommended Dosage for Treatment of Influenza Initiate treatment with oseltamivir phosphate for oral suspension within 48 hours of influenza symptom onset. Adults and Adolescents (13 years of age and older) The recommended oral dosage of oseltamivir phosphate for oral suspension for treatment of influenza in adults and adolescents 13 years and older is 75 mg twice daily (12.5 mL of oral suspension twice daily) for 5 days.

The effective dosage of Tamiflu (Oseltamivir) pills for treatment of influenza in:

  • Adults and adolescents (13 years and older) is 75 mg twice daily for 5 days.
  • Pediatric patients (2 weeks of age through 12 years of age) is based on weight, as shown in Table 1.

2.3 Recommended Dosage for Prophylaxis of Influenza Initiate post-exposure prophylaxis with oseltamivir phosphate for oral suspension within 48 hours following close contact with an infected individual. Adults and Adolescents (13 years of age and older) The recommended dosage of oseltamivir phosphate for oral suspension for prophylaxis of influenza in adults and adolescents 13 years and older is 75 mg orally once daily (12.5 mL of oral suspension once daily) for at least 10 days following close contact with an infected individual and up to 6 weeks during a community outbreak.

The effective dosage of Tamiflu (Oseltamivir) pills for prophylaxis of influenza in:

  • Adults and adolescents (13 years and older) is 75 mg once daily for at least 10 days following close contact with an infected individual and up to 6 weeks during a community outbreak.
  • Pediatric patients (1 year to 12 years of age) is based on weight, as shown in Table 1 2.

From the Research

Effective Dosage of Tamiflu (Oseltamivir)

The effective dosage of Tamiflu (Oseltamivir) pills is as follows:

  • For adults and children aged 1 year and older, the recommended dosage is 75 mg twice daily for 5 days 3, 4
  • For children under 1 year of age, a liquid formulation of oseltamivir (2 mg/kg twice daily for 5 days) has been shown to be effective 3
  • Higher doses of oseltamivir (150 mg twice daily) have been studied, but no significant additional benefit was found for adults hospitalized with influenza A, although an improved virologic response was seen in influenza B patients 5
  • The standard dose of 75 mg twice daily for 5 days has been shown to be effective in reducing the duration and severity of influenza symptoms, as well as the risk of complications and mortality 3, 6, 4

Special Populations

  • For patients with renal impairment, the dosage of oseltamivir may need to be adjusted, with a recommended dose of 75 mg twice daily for patients with creatinine clearance of 40-60 mL/minute 5
  • For patients with hepatic impairment, the pharmacokinetics of oseltamivir are not significantly affected, and no dose adjustment is recommended 7

Administration

  • Oseltamivir can be taken with or without food, although gastrointestinal events such as nausea and vomiting may be less likely when taken with food 3
  • The drug should be initiated within 48 hours of symptom onset for optimal effectiveness 3, 6

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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