What Is Entecavir? Uses, Dosage, and What You Need to Know in 2026

If you've been diagnosed with chronic hepatitis B, there's a good chance your doctor has mentioned entecavir. It's one of the two most recommended treatments for hepatitis B in the world—and for good reason. Here's everything you need to know about this medication in plain English.

What Is Entecavir?

Entecavir is an antiviral medication used to treat chronic hepatitis B virus (HBV) infection. It is sold under the brand name Baraclude, originally manufactured by Bristol-Myers Squibb. Since the patent expired (around 2015 in the US), generic entecavir has been available from multiple manufacturers.

Entecavir belongs to a class of drugs called nucleoside reverse transcriptase inhibitors (NRTIs). It works by blocking the hepatitis B virus from making copies of itself, which reduces the amount of virus in your blood and helps prevent liver damage over time.

Entecavir was FDA-approved in March 2005. It is on the World Health Organization's List of Essential Medicines, meaning it's recognized as one of the most important medications in global healthcare.

What Does Entecavir Treat?

Entecavir is FDA-approved for:

• Chronic hepatitis B virus (HBV) infection in adults and children 2 years and older who weigh at least 22 pounds (10 kg)
• Patients must have active viral replication and evidence of active disease (elevated liver enzymes or liver damage on biopsy)

Entecavir does not cure hepatitis B and does not prevent you from spreading it to others. It controls the virus, keeps it suppressed, and helps prevent complications like cirrhosis and liver cancer.

What Are the Dosage Forms of Entecavir?

Entecavir comes in three forms:

• 0.5 mg film-coated tablet — standard dose for most treatment-naive adults and adolescents ≥16 years
• 1 mg film-coated tablet — for patients with lamivudine-resistant hepatitis B or decompensated liver disease
• 0.05 mg/mL oral solution — for children ≥2 years or adults who cannot swallow tablets; weight-based dosing

How Do You Take Entecavir?

Entecavir is taken once a day by mouth. The most important rule: take it on an empty stomach—at least 2 hours after eating and at least 2 hours before your next meal. Food significantly reduces how much of the drug is absorbed into your bloodstream (up to 44% lower peak blood levels with a high-fat meal).

Take it at the same time every day to keep blood levels consistent. If you forget a dose, take it as soon as you remember—unless it's almost time for your next dose, in which case skip it and continue your regular schedule. Never take two doses at once.

How Long Do You Take Entecavir?

For most patients with chronic hepatitis B, entecavir is a long-term—often lifelong—treatment. This is because entecavir suppresses the virus but does not eliminate it from your body. If you stop taking it, the virus typically rebounds.

In some patients who achieve HBeAg seroconversion (a key milestone in hepatitis B treatment), doctors may discuss whether it is safe to stop treatment after a defined period of consolidation. This decision must be made carefully by your hepatologist or gastroenterologist based on your individual HBV status.

Who Should Not Take Entecavir?

Entecavir is not recommended for:

• People with untreated HIV infection — risk of HIV drug resistance development
• Children under 2 years of age or under 10 kg
• People allergic to entecavir or any ingredient in the tablet or solution

Key Facts at a Glance

• Generic name: entecavir
• Brand name: Baraclude
• Drug class: Nucleoside reverse transcriptase inhibitor (NRTI)
• FDA approved: March 2005
• Controlled substance: No
• Typical dose: 0.5 mg once daily (treatment-naive); 1 mg once daily (lamivudine-resistant or decompensated)
• Cash price with coupon: $11–$31 per 30-tablet supply with GoodRx or SingleCare

Ready to fill your prescription? medfinder can help you find which pharmacies near you have entecavir in stock. Want to understand more about how entecavir works? See our guide: How Does Entecavir Work?.