Oseltamivir is an influenza neuraminidase inhibitor indicated for the following conditions-

• Treatment of influenza in patients 1 year and older who have been symptomatic for no more than 2 days.
• Prophylaxis of influenza in patients 1 year and older

Influenza

Important Limitations of Use:

• Efficacy has not been established in patients who begin treatment after 48 hours of onset of symptoms.
• It is not a replacement for annual influenza vaccination.
• There is no evidence of efficacy for illness caused by agents other than influenza viruses A and B.
• When deciding whether to use, consider the available information on influenza drug susceptibility patterns and treatment effects.

Treatment of influenza

• Adults and adolescents (≥13 years): 75 mg twice daily for 5 days
• Pediatric patients (≥1 year): Based on weight twice daily for 5 days
• Renally impaired patients (creatinine clearance 10-30 mL/min): Reduce to 75 mg once daily for 5 days 

Prophylaxis of influenza

• Adults and adolescents (≥13 years): 75 mg once daily for at least 10 days - Community outbreak: 75 mg once daily for up to 6 weeks
• Pediatric patients (≥1 year): Based on weight once daily for 10 days.
• Community outbreak: Based on weight once daily for up to 6 weeks
• Renally impaired patients (creatinine clearance 10-30 mL/min): Reduce to 75 mg once every other day or 30 mg once daily 

Most common adverse reactions of oseltamivir are as follows-

• Nausea
• vomiting
• diarrhea
• abdominal pain 
• skin rash
• hypersensitivity

Nausea

Vomiting

Diarrhea

Rash

• Oseltamivir post-marketing experience has revealed cases of anaphylaxis and serious skin reactions such as toxic epidermal necrolysis, Stevens-Johnson Syndrome, and erythema multiforme. If an allergic-like reaction occurs or is suspected, Oseltamivir should be discontinued and appropriate treatment instituted.
• Influenza can cause a variety of neurologic and behavioral symptoms, including hallucinations, delirium, and abnormal behavior, which can lead to death in some cases. These events can occur in the context of encephalitis or encephalopathy, but they can also occur in the absence of obvious severe disease.
• Serious bacterial infections may begin with influenza-like symptoms, or they may coexist with or occur as complications of influenza. Oseltamivir has not been shown to be effective in preventing such complications.