What is Influenza?
Influenza, commonly known as the flu, is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness, and at times can lead to death. The best way to prevent the flu is by getting a flu vaccine each year.
What are Influenza Antivirals?
Influenza antivirals are medications used to treat and sometimes prevent influenza. These drugs can lessen the severity and duration of symptoms and help reduce the risk of complications such as pneumonia. The primary classes of influenza antivirals include neuraminidase inhibitors and polymerase inhibitors.
How Do Neuraminidase Inhibitors Work?
Neuraminidase inhibitors, such as [oseltamivir](https://www.ncbi.nlm.nih.gov/pubmed/), [zanamivir](https://www.ncbi.nlm.nih.gov/pubmed/), and [peramivir](https://www.ncbi.nlm.nih.gov/pubmed/), work by blocking the function of the viral neuraminidase protein, preventing the release of new virus particles from infected cells. This action helps to reduce the spread of the virus within the body.
How Do Polymerase Inhibitors Work?
Polymerase inhibitors, such as [baloxavir marboxil](https://www.ncbi.nlm.nih.gov/pubmed/), target the viral polymerase enzyme, which is essential for the replication of the viral genome. By inhibiting this enzyme, these drugs can significantly reduce viral replication and help control the infection.
When Should Antivirals Be Administered?
For the greatest benefit, antivirals should be administered within 48 hours of the onset of flu symptoms. Early treatment is crucial to reduce the severity and duration of the illness. However, antivirals can still be beneficial if started later, especially in hospitalized patients or those at high risk for complications.
Who Should Receive Antiviral Treatment?
Antiviral treatment is recommended for anyone with confirmed or suspected influenza who is:
- Hospitalized
- At high risk for complications (e.g., young children, elderly, pregnant women, and individuals with certain chronic medical conditions)
- Experiencing severe, complicated, or progressive illness
Can Antivirals Be Used for Prevention?
Yes, antivirals can be used for [chemoprophylaxis](https://www.ncbi.nlm.nih.gov/pubmed/) to prevent influenza in certain situations, such as outbreaks in long-term care facilities or in individuals who cannot receive the flu vaccine. However, vaccination remains the primary method of prevention.
What Are the Side Effects of Antivirals?
Common side effects of neuraminidase inhibitors may include nausea, vomiting, headache, and in some cases, neuropsychiatric effects such as confusion or delirium. Baloxavir marboxil is generally well-tolerated, with side effects including diarrhea and bronchitis. It is important to consult a healthcare provider for a complete list of potential side effects and to discuss any concerns.
Are There Concerns About Antiviral Resistance?
Yes, antiviral resistance is a concern. Influenza viruses can develop resistance to antiviral medications, which can reduce their effectiveness. Monitoring for resistance is essential, and healthcare providers may need to adjust treatment strategies based on the latest surveillance data.
Conclusion
Influenza antivirals play a crucial role in the management of influenza, particularly for those at high risk of complications. Early administration, appropriate patient selection, and ongoing vigilance for antiviral resistance are key factors in optimizing treatment outcomes. While antivirals are an important tool, vaccination remains the cornerstone of flu prevention.
