What Is Remdesivir?

An Antiviral Drug That Might Treat COVID-19

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Remdesivir is an intravenous antiviral drug currently being tested for effectiveness in treating the SARS-CoV-2 virus that causes COVID-19. Unlike the standard medications your doctor prescribes, it is not a treatment officially approved by the Food and Drug and Administration (FDA) based on its safety and effectiveness. Instead, remdesivir is considered an investigational product. Some evidence suggests that it might help with COVID-19. However, its effectiveness and safety are not yet clear.

Nurse taking care of sick person in hospital
 Jasmine Merdan/ Moment/ Getty Images


Remdesivir is not FDA-approved for any medical condition. Until now, it hasn’t been broadly available to medical providers as a treatment. It hasn’t gone through the intense scientific scrutiny over several years that is usually required for a drug to become available. Instead, it has been released by the FDA under something called an “emergency use authorization.”

What Is Emergency Use Authorization?

Under an emergency use authorization (EUA), the FDA will sometimes make certain treatments widely available to medical providers during an emergency situation, even if these haven’t gone through the full set of studies required for regular approval. A treatment might be given an EUA if there are no FDA-approved alternatives to treat a serious or life-threatening medical condition. A certain amount of evidence must suggest that the product is relatively safe and might effectively treat the medical issue.

Remdesivir was originally developed by manufacturers for hepatitis C, and later tried on the virus that causes Ebola (though it has never officially been approved for this use). The drug interferes with a virus’ ability to copy its RNA, a step needed for some types of viruses to successfully make copies and spread inside the body.

In laboratories, the drug has been shown to help block virus replication of several RNA-type viruses. Among these are Coronaviridae (the coronavirus family). Viruses in this family are responsible for severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and the novel coronavirus, SARS-CoV-2, that causes COVID-19.

Remdesivir and COVID-19

Before the COVID-19 pandemic, research already suggested that remdesivir might be effective at fighting coronaviruses. Studies in animals have shown potential, and some human studies (including in some studies treating Ebola), have indicated relative safety.

Early in the pandemic, clinicians began contacting the drug manufacturer of remdesivir, Gilead Sciences, to see if they could get access to the drug to treat some people with severe COVID-19. This is permitted under the FDA's guidelines for expanded access (also called "compassionate use") which allows the use of investigational products for life-threatening medical situations when no FDA-approved treatments are available.

An international study of 53 people with severe COVID-19 suggested that the drug may help people recover from the disease. However, 13% of people with severe COVID-19 in this study died. This was an uncontrolled trial, which means that outcomes weren’t compared to people with COVID-19 who didn’t take remdesivir.

A more rigorous “controlled” clinical trial sponsored by the National Institute of Allergy and Infectious Diseases earned remdesivir EUA status from the FDA. This trial, which began on February 21 and was reviewed on April 27, involved over 1,000 people with advanced COVID-19, and marked the first study of the drug in the U.S.

On May 1, 2020, the Food and Drug Administration granted emergency use authorization (EUA) to treat severe COVID-19 in children and adults, making it more broadly available to doctors.

Preliminary information from the trial showed that people who took remdesivir recovered quicker than those who did not, and people who took remdesivir were more likely to survive. However, a smaller study out of China of over 200 patients did not find a similar improvement in recovery time and survival.

Remdesivir is currently being studied in at least five different clinical trials worldwide. These studies will help determine if the drug is safe and effective. Some of these studies will compare remdesivir to other potential treatments under investigation.

These studies will also look at other aspects surrounding remdesivir treatment, such as:

  • Optimal dosing
  • Length of treatment
  • At what point in the infection to administer it
  • Effectiveness in people with less severe symptoms

If remdesivir is found to be ineffective and/or markedly unsafe, the FDA will revoke its EUA.

What to Tell Your Doctor 

Your doctor might consider trying remdesivir if you have COVID-19, particularly if your symptoms are severe.

Make sure your medical provider knows about your medical history before you start taking remdesivir. It's important that they know if you have kidney or liver problems, or if you have any other serious medical conditions.

You should also let your clinician know if you are pregnant or might be pregnant. Your medical provider should also know about any medicines you are taking, including anything over-the-counter.

Depending on the situation, one or more investigational treatments might be available to treat COVID-19. Discuss your options with your physician. You do not have to be treated with remdesivir or any other investigational treatment. Instead, you could opt for standard supportive medical treatment while your body fights the infection.

Dosage and Administration

Remdesivir is given through an intravenous line over the course of 30 minutes to two hours. It may be given once a day for up to ten days, but that may depend on your condition. People who are not as ill may only receive the drug for five days.

Current guidelines recommend a dose of 200 mg on the first day followed by a daily dose of 100 mg for people who weigh 40 kg and over. Dosage may vary for pediatric and low-weight patients.

Side Effects

Some of the most common known side effects from remdesivir are:

  • Diarrhea
  • Abnormal liver function (as assessed by blood tests)
  • Rash
  • Kidney problems
  • Low blood pressure
  • Nausea and vomiting

Since remdesivir is given through an intravenous infusion, certain other side effects are possible, like bruising of the skin, soreness, or swelling where the needle is inserted. A small minority of people may experience something called an “infusion reaction” shortly after taking the drug. This is a type of allergic reaction that might cause problems like very low blood pressure, and it might make it necessary to stop taking remdesivir.

In one study, 23% of people treated with remdesivir had serious side effects, including dysfunction of multiple organs and septic shock. However, because this data is from a single small study, it’s not clear if rates of serious side effects are typically that high.

While taking remdesivir, your healthcare provider will carefully monitor you for potential side effects. For example, you’ll need regular blood tests to see that your kidneys and liver are functioning well, both before starting therapy and while you receive the drug.

A Word From Verywell

It’s important to emphasize that remdesivir has still only been studied in a limited way in people. The drug may cause other important side effects in some individuals that we don’t yet know about. The clinical trials looking at remdesivir in COVID-19 may demonstrate it's effective and well-tolerated, but they could also reveal additional safety concerns.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.

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9 Sources
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