What are the advantages and disadvantages of Oseltamivir (Tamiflu)?

From the Guidelines

Tamiflu (oseltamivir) is generally recommended for treating and preventing influenza in certain high-risk individuals, but it has both benefits and drawbacks to consider.

Pros of Tamiflu:

• Can reduce the duration of flu symptoms by 1-2 days if taken within 48 hours of symptom onset 1
• May decrease the severity of flu symptoms
• Can help prevent flu in exposed individuals
• Particularly beneficial for high-risk groups (elderly, young children, immunocompromised)

Cons of Tamiflu:

• Common side effects include nausea, vomiting, and headache
• Rare but serious side effects like neuropsychiatric events have been reported
• Expensive compared to over-the-counter flu remedies
• May contribute to antiviral resistance if overused

Typical Dosing:

• For treatment, the typical dosing is 75 mg twice daily for 5 days in adults, and for children, the dosing is based on body weight, with 30 mg, 45 mg, or 60 mg twice daily for 5 days, depending on the child's weight 1
• For prevention, it's 75 mg once daily for at least 10 days after exposure

Mechanism of Action:

Tamiflu works by inhibiting the neuraminidase enzyme in influenza viruses, preventing their release from infected cells and reducing viral spread. It's most effective when started early in the course of illness, so prompt consultation with a healthcare provider is crucial if flu is suspected.

Important Considerations:

While Tamiflu can be helpful, it's not a substitute for annual flu vaccination, which remains the primary method of influenza prevention. Additionally, treatment with oseltamivir for children with presumed serious, complicated, or progressive disease, irrespective of influenza immunization status or whether illness began 48 hours before admission, continues to be recommended by the AAP, CDC, and Infectious Diseases Society of America 1.

From the FDA Drug Label

5 WARNINGS AND PRECAUTIONS 5.1 Serious Skin/Hypersensitivity Reactions 5.2 Neuropsychiatric Events 5.3 Risk of Bacterial Infections 5.4 Fructose Intolerance in Patients with Hereditary Fructose Intolerance 6 ADVERSE REACTIONS 6.1 Clinical Trials Experience 6.2 Postmarketing Experience

The advantages and disadvantages of Oseltamivir (Tamiflu) are not directly stated in the provided drug label. However, the label does mention several warnings and precautions, including:

• Serious skin/hypersensitivity reactions
• Neuropsychiatric events
• Risk of bacterial infections
• Fructose intolerance in patients with hereditary fructose intolerance It also lists adverse reactions experienced during clinical trials and postmarketing experience. However, the benefits of the drug, such as its efficacy in treating and preventing influenza, are implied in the indications and usage section 2. The decision to use Oseltamivir should be made based on a careful consideration of these potential risks and benefits.

From the Research

Advantages of Oseltamivir (Tamiflu)

• Oseltamivir reduces the duration of symptomatic illness and hastens the return to normal levels of activity when initiated promptly in patients with naturally acquired influenza 3
• The drug reduces the severity of illness by up to 38% compared with placebo when initiated within 36 hours of symptom onset 3
• Oseltamivir also reduces the incidence of secondary complications and the use of antibacterials 3
• The drug is effective in the treatment of children with influenza, and data suggest that it may also be of use in high-risk populations such as the elderly or those with chronic cardiac or respiratory disease 3, 4
• Oseltamivir has demonstrated efficacy when used for seasonal or household prophylaxis, preventing the development of naturally acquired influenza by >70% compared with placebo in unvaccinated otherwise healthy adults 3

Disadvantages of Oseltamivir (Tamiflu)

• Oseltamivir is not recommended for patients with mild influenza or those suffering from different viral infections, as it may not provide significant benefits and may increase the risk of resistance 4
• The drug may cause gastrointestinal events, such as nausea and vomiting, although these are typically mild and transient 3, 5
• There is limited evidence to support the use of oseltamivir outside of labeled recommendations, such as administering the drug 48 hours or more after the onset of symptoms, doubling the standard dose, or continuing therapy for more than five days 6
• Oseltamivir may not be effective in reducing the risk of illness in household contacts of infected persons when administered more than 48 hours after symptom onset in the infected person 3
• The emergence of antiviral resistance during and after the 2009 pandemic is a concern, and the implications of changes in susceptibility of circulating influenza viruses to oseltamivir and other antiviral agents need to be considered 7