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Casirivimab and imdevimab

Generic name: casirivimab and imdevimab (Regen-Cov)KAS-i-RIV-i-mab-and-im-DEV-i-mab ]
Brand name: Regen-Cov
Dosage form: injectable solution (1332 mg/11.1 mL-1332 mg/11.1 mL; 1332 mg/11.1 mL-300 mg/2.5 mL; 300 mg/2.5 mL-1132 mg/11.1 mL; 300 mg/2.5 mL-300 mg/2.5 mL; 600 mg-600 mg/10 mL)
Drug class: Antiviral combinations

Medically reviewed by on Apr 18, 2022. Written by Cerner Multum.

What is casirivimab and imdevimab?

Due to the high frequency of the Omicron BA.2 sub-variant, this drug is not currently authorized in any US region; therefore, this drug may not be administered for treatment of COVID-19 under the EUA until further notice by the US FDA.

Casirivimab and imdevimab are experimental medicines being studied for use in treating conditions caused by coronavirus. It is not yet known if casirivimab or imdevimab are safe and effective.

Casirivimab and imdevimab are also for use in people who have been exposed to COVID-19 and:

Casirivimab and imdevimab are for use in adults and children at least 12 years old who weigh at least 88 pounds (40 kilograms).

The risk of COVID-19 symptoms becoming severe may be higher in people who:

There also may be a higher risk of severe COVID-19 symptoms in pregnant women and in adults who are 65 and older.

Casirivimab and imdevimab are mixed together into a single solution called Regen-Cov.

Casirivimab and imdevimab have not been approved to treat coronavirus or COVID-19. However, these medicines may help prevent the need for emergency medical care or admission to a hospital because of COVID-19. Regen-Cov is not authorized for use in people who are already in the hospital or receiving supplemental oxygen for COVID-19.

Casirivimab and imdevimab may also be used for purposes not listed in this medication guide.

Casirivimab and imdevimab side effects

Get emergency medical help if you have signs of an allergic reaction: hives, itching; difficult breathing; swelling of your face, lips, tongue, or throat.

Some side effects may occur during the injection. Tell your caregiver right away if you have:

Call your doctor if you have new or worsening symptoms after the infusion, such as fever, confusion, weakness, tiredness, trouble breathing, or fast or slow heartbeats.

Less serious side effects may also occur, or you may have none at all. Not all possible side effects are known.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


Due to the high frequency of the Omicron BA.2 sub-variant, this drug is not currently authorized in any US region; therefore, this drug may not be administered for treatment of COVID-19 under the EUA until further notice by the US FDA.

Before taking this medicine

Tell your doctor if you have ever had:

COVID-19 is more likely to cause serious illness or death in a pregnant woman. Not all risks are known yet, but being treated with casirivimab and imdevimab is likely to be less harmful than being infected with COVID-19 during pregnancy.

How is casirivimab and imdevimab given?

Regen-Cov is injected under the skin or into a vein by a healthcare provider.

When injected into a vein, Regen-Cov is given slowly over 20 to 50 minutes or longer. When injected under the skin, Regen-Cov is given as 2 to 4 separate injections into different areas of your body.

You will be watched for a short time after injection, to make sure you do not have an allergic reaction.

Regen-Cov is usually given as only one dose as soon as possible after you are exposed to or test positive for COVID-19, or within 10 days after the start of symptoms. You may need additional monthly doses if you continue to be exposed to COVID-19.

Being treated with Regen-Cov will not make you less contagious to other people. Keep using infection control methods such as self-isolation, social distancing, hand-washing, using protective face covering, disinfecting surfaces you touch a lot, and not sharing personal items with others.

Regen-Cov also may not keep you from becoming infected with coronavirus again. Being treated with this drug combination could also affect your body's immune response to a coronavirus vaccine. Casirivimab and imdevimab are still being studied and all of their risks are not yet known.

What happens if I miss a dose?

Call your doctor for instructions if you are on a monthly dose schedule and you miss an appointment for your injection.

What happens if I overdose?

In a medical setting an overdose would be treated quickly.

What should I avoid while receiving casirivimab and imdevimab?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

What other drugs will affect casirivimab and imdevimab?

Other drugs may affect casirivimab and imdevimab, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all other medicines you use.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.