What Is Remdesivir?

An Antiviral Drug Approved to Treat COVID-19

Remdesivir is an intravenous (IV) antiviral drug used to fight the SARS-CoV-2 virus that causes COVID-19. Remdesivir is the generic name for the medication. The brand name is Veklury. The drug was approved by the Food and Drug Administration (FDA) in October 2020.

This article will explain how remdesivir works, the history of its use for COVID-19, and its possible side effects.

Nurse taking care of sick person in hospital

 Jasmine Merdan / Moment / Getty Images


Remdesivir was the first medication specifically approved by the FDA to treat COVID-19. Prior to that, it was allowed to be used as an investigational drug under what's known as 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 to treat 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 showed potential, and some human studies (including in some studies treating Ebola), 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.

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

Later that year, remdesivir was approved based on three randomized, controlled clinical trials of people with mild-to-severe COVID-19. These trials had mixed results.

In one, 1,062 people hospitalized with COVID-19 were given either remdesivir or a placebo (an inactive treatment). Those who received remdesivir recovered after 10 days, on average, while those who received a placebo took 15 days to recover. This was defined as being released from the hospital or no longer needing supplemental oxygen and other ongoing care.

A second trial found that people given remdesivir for five days had better odds of improvement compared to those who received standard supportive care, but no significant difference was seen in those who received it for 10 days. And a third trial found no better outcomes with remdesivir use compared to placebo.

Remdesivir is specifically approved for use only in people age 12 or older who weigh at least 40 kilograms (kg), or about 88 pounds. However, it is still authorized under an EUA for younger patients and those who weigh less than 40 kg. The drug is given by IV, and the FDA says it should be given in a hospital or other setting providing an equivalent level of care.

According to the National Institutes of Health's treatment guidelines for COVID-19, remdesivir is recommended for people who are hospitalized and need supplemental oxygen. If a person requires high-flow oxygen, remdesivir may be given along with the steroid dexamethasone.

It's also one of the treatment options for people who aren't yet hospitalized but who are at high risk of developing severe COVID-19. However, it isn't the first choice for this group.


Remdesivir is approved to treat COVID-19 in those who are hospitalized and require supplemental oxygen, or those who aren't hospitalized but at risk of developing severe disease.

What to Tell Your Doctor 

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.

COVID-19 treatments have advanced since remdesivir was approved, and other medications are now available. Depending on your situation, one or more investigational treatments might be more appropriate for you. Discuss your options with your physician.

Dosage and Administration

For people being treated in the hospital for COVID-19, remdesivir may be given once a day for at least five days or up to 10 days. For prevention of severe COVID in high-risk people who aren't hospitalized, the recommended treatment course is three days.

The drug is given through an IV line over the course of 30 minutes to two hours. Current guidelines recommend a dose of 200 milligrams (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 IV 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.


Remdesivir was one of the earliest treatments for COVID-19 and the first one specifically approved by the FDA to treat the infection. It is recommended for people who are hospitalized with COVID-19 and who require supplemental oxygen. It's also one of the options available for people who aren't yet hospitalized but who are at risk of a severe infection, but newer alternatives are preferred for that group.

Frequently Asked Questions

  • What should I know about remdesivir?

    Remdesivir is an antiviral drug that is approved by the Food and Drug Administration to treat COVID-19. It is given intravenously in a hospital or similar setting. It is used to prevent worsening disease in people who are hospitalized and on supplemental oxygen, or those who aren't yet hospitalized but at risk of severe COVID-19.

  • Can remdesivir shorten COVID-19 recovery time?

    For some people, yes. In one of the clinical trials that led to remdesivir's approval, people who received the drug recovered five days faster, on average, compared to those who got a placebo (10 days vs. 15 days).

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.

10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. FDA approves first treatment for COVID-19.

  2. Food and Drug Administration. Emergency use authorization.

  3. Eastman RT, Roth JS, Brimacombe KR, et al. Remdesivir: a review of its discovery and development leading to emergency use authorization for treatment of COVID-19. ACS Cent Sci. 2020;acscentsci.0c00489. doi:10.1021/acscentsci.0c00489 

  4. Amirian ES, Levy JK. Current knowledge about the antivirals remdesivir (GS-5734) and GS-441524 as therapeutic options for coronaviruses. One Health. 2020;9:100128. doi:10.1016/j.onehlt.2020.100128

  5. Food and Drug Administration. Coronavirus (COVID-19) update: FDA issues emergency use authorization for potential COVID-19 treatment.

  6. National Institutes of Health. Therapeutic management of hospitalized adults with COVID-19.

  7. National Institutes of Health. Therapeutic management of nonhospitalized adults with COVID-19.

  8. Food and Drug Administration. Fact sheet for health care providers emergency use authorization (EUA) of remdesivir (GS-5734TM)

  9. Gilead. Remdesivir prescribing information.

  10. Grein J, Ohmagari N, Shin D, et al. Compassionate use of remdesivir for patients with severe Covid-19. N Engl J Med. doi:10.1056/NEJMoa2007016

By Ruth Jessen Hickman, MD
Ruth Jessen Hickman, MD, is a freelance medical and health writer and published book author.