What is Oseltamivir Used For?

Published April 23rd, 2020 by Chris Riley
Fact Checked by
Chris Riley

Anyone who has experienced the symptoms of the seasonal flu knows how uncomfortable the illness can be. The ‘flu’ is often a loosely used term to describe symptoms of a fever, cold, body ache and fatigue. All of these symptoms can be caused by different infections. Most of the time, they are due to viral infections but sometimes they can be caused by bacterial infections that need to be treated with antibiotics before getting better. Although we’ve heard people describe cases of the flu like ‘stomach flu’, the Influenza virus causes a true seasonal flu. This virus infects human cells in a specific way that is different from other common viruses like the Rhinovirus family that can cause the common cold. Why does it matter to know what type of virus causes your flu symptoms? This is because the likelihood of the illness becoming severe and the treatment recommended for the illness will be different depending on which virus causes the infection. 

Many times, the seasonal flu will get better on its own with proper rest and taking over-the-counter medications like Tylenol to reduce fever.  There is some controversy within the medical field about the best way to treat the flu. There are several prescription anti-viral medications available to treat infections caused by the Influenza virus. These include oseltamivir (also commonly known as the brand, Tamiflu), zanamivir, peramivir and baloxavir. 

What is Oseltamivir? Oseltamivir, or Tamiflu, is an anti-Influenza drug that is in very high demand during the flu season. Although the drug can be quite expensive and can cost up to $100 for a course, the drug is extremely popular in treating the flu. The drug is so popular that in December 2019, there was speculation that it may be made available over-the-counter at some point in the future. In some countries like Japan, a prescription is not required to purchase oseltamivir.  Currently in the United States, a prescription is necessary to purchase the drug. 

Here are the major Food and Drug Administration (FDA)-approved uses for oseltamivir.

Influenza A and B infections 

Two types of Influenza viruses cause the seasonal flu. These two types are Influenza Type A and B. Type C can cause mild symptoms in humans. The annual flu shot that is recommended at the onset of flu season in the United States is a vaccination against the Influenza Type A and B viruses that cause the seasonal flu. It is important to get the flu shot whether or not you believe you are at risk for contracting the flu. Studies have shown that the flu shot can reduce the chance of getting the illness by between 40-60%. 

The main use of oseltamivir is to treat the seasonal flu and its mechanism of action is specific against the Influenza viruses. The drug works by inhibiting the neuraminidase enzyme that the virus uses to replicate itself within human cells. Without the ability to reproduce itself within the human body, the virus cannot survive. 

There is some controversy in using this drug due to the debate within the medical field of how effective it actually is. We now know that the drug can shorten the duration of the illness by an average of one day, or even longer in older patients or high-risk individuals. It has been shown that the drug is most effective if taken within the first 48 hours of experiencing symptoms. Often, patients do not take the drug so soon after experiencing symptoms because initial symptoms of the flu can appear to be the same as a common cold or an infection caused by another group of viruses for which oseltamivir will not be effective. Still, many physicians argue that the drug should be administered to individuals who are at high-risk. Individuals in this group include people above the age of 65, pregnant women, children under the age of 5, individuals with pre-existing conditions that affect the heart or respiratory system like asthma, hospitalized patients, and people with conditions that can suppress the immune system like HIV. Oseltamivir is FDA-approved for use in anyone above the age of 2 weeks. In any case, the data suggest that oseltamivir does not reduce complications due to the flu like secondary infections that result in pneumonia or another secondary bacterial infection. 

Avian Flu (H5N1/H7N9) 

Avian or Bird Flu is caused by avian Influenza Type A viruses that normally affect only birds. Rarely, when they transmit to humans they can cause a ‘flu’ like illness with symptoms that can be mild or severe. Symptoms include conjunctivitis, fever, cough, sore throat, and muscle aches. Two strains of avian Influenza Type A have been detected in humans. These are the H5N1 strain that caused an epidemic in Southeast Asia in 2005, and the Asian H7N9 strain. In both cases, the Centers for Disease Control and Prevention (CDC) recommend treatment with an anti-viral neuraminidase inhibitor like oseltamivir. During the 2005 Avian flu epidemic, the branded form of oseltamivir, Tamiflu, was widely used for treatment. In preparation for a possible spread of the epidemic, other countries like the United States, Australia and the United Kingdom also stockpiled Tamiflu. Like in the case of treating seasonal flu, taking oseltamivir can help shorten the duration of the illness caused by the Avian flu. It is also recommended as a preventative measure for high-risk individuals. 

Swine Flu (H1N1) 

Swine Flu is caused by the Influenza Type A virus H1N1. In 2009, there was a global pandemic of Swine Flu that also spread across North America. The virus is thought to have originated in pigs, which then spread to infect humans. Symptoms of the Swine Flu are similar to the seasonal flu and include fever, cough, fatigue, body ache and chills. The duration of Swine Flu is also similar to the seasonal flu and usually lasts around a week. In most cases, Swine Flu will resolve on its own with rest and home treatment. The CDC recommends the use of anti-viral agents like oseltamivir for treatment in individuals who are in the high-risk group or are hospitalized. Taking oseltamivir within 48 hours of the onset of symptoms can reduce the duration of the illness. 

COVID-19 clinical trials 

As the number of COVID-19 cases keeps increasing around the world, some drugs are being investigated for their possibility as therapeutic agents for treatment. COVID-19 is caused by a novel coronavirus, SARS-CoV-2. This virus is different from the Influenza viruses, so standard treatment protocols that work for Influenza have not been sufficient for treating COVID-19. Several anti-viral agents are being investigated as possible options for treatment of COVID-19 and oseltamivir is one of them. This drug has been enrolled in clinical trials to test whether it is safe and effective in treating COVID-19. One example is the clinical trial that is currently ongoing in Bangkok (NCT04303299). Until the results of the clinical trial come back, whether Oseltamivir can work for the treatment of oseltamivir is not known. 

What is Oseltamivir not used for? 

Oseltamivir does not work to treat infections caused by bacterial species. The drug is a specific anti-viral agent that affects viruses that use neuraminidase to infect human cells. This means that taking oseltamivir for a bacterial infection will not help resolve the infection or alleviate symptoms due to it. Another common misconception about oseltamivir is that it works to treat a common cold. Oseltamivir is not effective in treating illnesses caused by other viruses. This includes the Rhinovirus family that frequently causes the common cold. Taking Oseltamivir for the common cold is not likely to help you feel better. Therefore, it is important to take oseltamivir only as prescribed by your physician. The drug is associated with some side effects, so taking it for an indication that it will not work for is not likely to make your condition better. However, if you are prescribed oseltamivir for the seasonal flu, your doctor has judged that any side effects of Oseltamivir might give you will be outweighed by its benefits. 

How to purchase Oseltamivir at a discounted price 

If you are prescribed oseltamivir by your physician, you will find that the price of the drug can be quite steep. It can cost up to $100 for a course of the medication. If you have a high-copay with your health insurance, or if you are not covered for prescription drugs, you can still find savings on this drug with a drug discount card. The discount card available from USA Rx can give you more than 50% savings on Tamiflu. Signing up for the card is free and convenient. The card can be printed and presented at your pharmacy when filling your prescription. To find out how much the card can save you at different pharmacies, you can check the price of the drug with the discount applied on the website here. Whether you are prescribed oseltamivir as a preventative measure, or if it is to treat the seasonal flu, with the lowered price you can get with the discount card you will be on your way to feeling better soon. 

Published April 23rd, 2020 by Chris Riley
Fact Checked by
Chris Riley

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