TAMIFLU (oseltamivir phosphate) is available as capsules containing 30 mg, 45 mg, or. 9. 75 mg oseltamivir for oral use, in the form of oseltamivir phosphate, and as a powder for. Adults and Adolescents (13 years of age and older) The recommended oral dosage of TAMIFLU for treatment of influenza in adults and adolescents 13 years and older is 75 mg twice daily (one 75 mg capsule or 12.5 mL of oral suspension twice daily) for 5 days. The recommended dosage of TAMIFLU for prophylaxis of influenza in adults and adolescents 13 years and older is 75 mg orally once daily (one 75 mg capsule or 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. How to use Tamiflu. Read the Patient Information Leaflet if available from your pharmacist before you start taking this medicine. If you have any questions, consult your doctor or pharmacist. The recommended oral dosage of Tamiflu for treatment of influenza in adults and adolescents 13 years and older is 75 mg twice daily (one 75 mg capsule or 12.5 mL of oral suspension twice daily) for 5 days. See Dosage section for specific weight- and age-based dosage recommendations. Oseltamivir dose of 15 mg or less: Prepare a 37.5 mL suspension using three (3) 75-mg capsules (225 mg oseltamivir), 2.5 mL of water, and 34.5 mg of recommended vehicle. The recommended oral dosage of TAMIFLU for treatment of influenza in adults and adolescents 13 years and older is 75 mg twice daily (one 75 mg capsule or 12.5 mL of oral suspension twice daily) for 5 days. Tamiflu Dosage for the Treatment of Flu in Adults and Adolescents The recommended starting dosage for most adults and adolescents over the age of 13 is 75 mg, twice a day, for five days. Tamiflu should be started within two days of first noticing flu symptoms. Tamiflu Prophylaxis Information Antiviral Agent Activity Against Use Recommended For Not Recommended for Use in Children Adults Duration Tamiflu Dosage Tamiflu is available in 30 milligram (mg) and 75 mg tablets and a 6 mg/milliliter (ml) syrup. The usual dose is 75 mg of Tamiflu twice a day for 5 days for adults who have symptoms.