Drug Database: Entecavir

What is entecavir?

Entecavir is an antiviral prescription medicine approved by the U.S. Food and Drug Administration (FDA) for the treatment of chronic hepatitis B virus infection (HBV) in adults and children 2 years of age and older who meet certain requirements, as determined by a health care provider.

HBV can be an opportunistic infection (OI) of HIV. An OI is an infection that occurs more frequently or is more severe in people with weakened immune systems—such as people with HIV—than in people with healthy immune systems. To learn more about OIs, read the HIVinfo What is an Opportunistic Infection? fact sheet.

To learn how HIV and HBV are connected, read the HIVinfo HIV and Hepatitis B fact sheet. The fact sheet includes information about how HBV is spread, symptoms of HBV, and treatment options.

How is entecavir used in people with HIV?

The Guidelines for the Prevention and Treatment of Opportunistic Infections in Adults and Adolescents with HIV and the Guidelines for the Prevention and Treatment of Opportunistic Infections in Children with and Exposed to HIV include recommendations on the use of entecavir to treat HBV in certain people with HIV/HBV coinfection.

The recommended uses may not always be consistent with FDA-approved uses of entecavir. See the Adult and Pediatric Opportunistic Infection Guidelines for complete information on recommended uses of entecavir in adults and children with HIV. Entecavir may have other recommended uses not listed above.

What should I tell my health care provider before taking entecavir?

Before taking entecavir, tell your health care provider:

• If you are allergic to entecavir or any other medicines. 
• About any medical conditions you have or have had, especially: 
  • Liver problems, including if you have ever had a liver transplant
  • Kidney problems, including if you are receiving dialysis
• If you have ever received medicine for HBV before.
• About anything that could affect your ability to take medicines, such as difficulty swallowing or remembering to take pills. 
• If you are pregnant or plan to become pregnant. Talk to your health care provider about the risks and benefits of taking entecavir during pregnancy. The Guidelines for the Prevention and Treatment of Opportunistic Infections in Adults and Adolescents with HIV may include other recommendations on the use of entecavir during pregnancy. Please refer to these guidelines for additional information.
• If you are breast/chestfeeding or plan to breast/chestfeed. For people with HIV in the United States, the Guideline recommends speaking with your health care provider to discuss options for feeding your baby. People with suppressed viral load have a less than 1% chance of transmitting HIV to their baby via their own milk.
• About other prescription and nonprescription medicines, vitamins, nutritional supplements, and herbal products you or your child are taking or plan to take. Entecavir may affect the way other medicines or products work, and other medicines or products may affect how entecavir work. Ask your health care provider if there are interactions between entecavir and the other medicines you or your child take.

Ask your health care provider about possible side effects from entecavir. Your health care provider will tell you what to do if you have side effects.

How should I take entecavir?

Take entecavir according to your health care provider’s instructions. Your health care provider will tell you how much entecavir to take and when to take it. Before you start entecavir and each time you get a refill, read any printed information that comes with your medicine.

How should entecavir be stored?

• Store entecavir tablets and oral solution at room temperature, 68°F to 77°F (20°C to 25°C). Store entecavir tablets and oral solution in the original outer carton, and keep the carton out of light.
• Keep entecavir in the container that it came in and keep the container tightly closed.
• Do not use entecavir if the original seal over the container opening is broken or missing.
• Throw away entecavir that is no longer needed or expired (out of date). Follow FDA guidelines on how to safely dispose of unused medicine.
• Keep entecavir and all medicines out of reach of children.

Where can I find more information about entecavir?

• Recommendations on the HIV-related uses of entecavir, from the Guidelines for the Prevention and Treatment of Opportunistic Infections in Adults and Adolescents with HIV and the Guidelines for the Prevention and Treatment of Opportunistic Infections in Children with and Exposed to HIV.
• This Patient Version drug summary is based on the following FDA label(s): Tablet (film coated), solution. The Patient Information section includes information for people taking entecavir.
• The American Hospital Formulary Service (AHFS) Patient Medication Information for entecavir available from MedlinePlus.
• Research studies related to entecavir, from ClinicalTrials.gov. (The ClinicalTrials.gov search can be modified so that you can get results that better match your interests. To learn more about the ClinicalTrials.gov search features, please see How to Search.)

Last Reviewed: May 8, 2023

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