Baraclude (Entecavir)
Antiviral medicine for chronic hepatitis B virus infection
Baraclude (entecavir) is a prescription antiviral medicine belonging to the nucleoside analogue class. It is used to treat chronic hepatitis B virus (HBV) infection in adults and children aged 2 years and older weighing at least 10 kg. Entecavir works by blocking the replication of the hepatitis B virus, reducing the viral load and helping to improve liver function. It is one of the first-line therapies recommended by international guidelines for chronic HBV management.
Quick Facts
Key Takeaways
- Baraclude (entecavir) is a first-line antiviral treatment for chronic hepatitis B recommended by WHO, EASL, and AASLD guidelines.
- It is effective in both treatment-naive patients and those with compensated or decompensated liver disease.
- The drug has a high genetic barrier to resistance, meaning viral resistance develops rarely in patients who have not received prior nucleoside therapy.
- Never stop taking Baraclude without medical supervision, as abrupt discontinuation can cause severe hepatitis flares.
- Common side effects include headache, fatigue, dizziness, and gastrointestinal disturbances, which are generally mild and manageable.
What Is Baraclude and What Is It Used For?
Quick Answer: Baraclude (entecavir) is an antiviral medication that treats chronic hepatitis B infection by blocking viral replication in the liver. It is approved for use in adults and children aged 2 years and older.
Baraclude contains the active substance entecavir, which belongs to a group of medicines known as nucleoside analogues. Entecavir is a guanosine nucleoside analogue with potent and selective activity against the hepatitis B virus (HBV) polymerase. It was first approved by the U.S. Food and Drug Administration (FDA) in 2005 and by the European Medicines Agency (EMA) shortly thereafter, and has since become one of the most widely prescribed treatments for chronic hepatitis B worldwide.
Chronic hepatitis B is a long-term infection of the liver caused by the hepatitis B virus. If left untreated, chronic HBV infection can lead to progressive liver damage, including fibrosis, cirrhosis, hepatocellular carcinoma (liver cancer), and ultimately liver failure. The World Health Organization (WHO) estimates that approximately 254 million people globally are living with chronic hepatitis B, and the disease causes more than 1.1 million deaths annually, predominantly from cirrhosis and liver cancer.
Baraclude works by inhibiting the HBV polymerase enzyme, which the virus needs to replicate its DNA. Specifically, entecavir is phosphorylated intracellularly to its active triphosphate form, which then competes with the natural substrate (deoxyguanosine triphosphate) for incorporation into the growing viral DNA chain. By doing so, it effectively blocks all three functional activities of the HBV polymerase: the priming step, the reverse transcription of the negative strand from the pregenomic messenger RNA, and the synthesis of the positive strand of HBV DNA. This triple inhibition results in a profound reduction in the amount of virus circulating in the blood (viral load).
Baraclude can be used in patients whose liver is damaged but still functions adequately (compensated liver disease) as well as in patients with more severe liver damage where the liver no longer functions properly (decompensated liver disease). In children and adolescents between 2 and 18 years of age, Baraclude is approved for use in those with compensated liver disease. The oral solution formulation is particularly useful for paediatric patients who may have difficulty swallowing tablets.
How Effective Is Entecavir?
Clinical trials have demonstrated that entecavir is highly effective at suppressing HBV DNA to undetectable levels. In the pivotal ETV-022 and ETV-027 studies in nucleoside-naive patients, entecavir achieved HBV DNA suppression to less than 300 copies/mL in approximately 67% of HBeAg-positive and 90% of HBeAg-negative patients at 48 weeks. Histological improvement, defined as a reduction in necroinflammatory activity without worsening fibrosis, was observed in approximately 70–72% of patients. Long-term studies extending beyond 5 years have shown that sustained viral suppression leads to reversal of fibrosis and even cirrhosis in a significant proportion of patients.
Entecavir has a high genetic barrier to resistance, which means that in treatment-naive patients, the development of resistance is exceedingly rare. In studies following patients for up to 6 years, the cumulative probability of genotypic resistance was only 1.2% in nucleoside-naive patients. However, in patients who have previously received lamivudine and developed resistance mutations (such as rtM204V/I), the risk of entecavir resistance is substantially higher because these mutations lower the genetic barrier. For lamivudine-resistant patients, the recommended dose of entecavir is doubled to 1 mg daily.
What Should You Know Before Taking Baraclude?
Quick Answer: Before starting Baraclude, inform your doctor about any kidney problems, HIV co-infection, pregnancy, or previous hepatitis B treatments. Do not stop taking the medication without medical guidance, as this can cause dangerous hepatitis flares.
Contraindications
You should not take Baraclude if you are allergic (hypersensitive) to entecavir or any of the other ingredients in the medication. The inactive ingredients in Baraclude tablets include crospovidone, lactose monohydrate, magnesium stearate, microcrystalline cellulose, and povidone. The film coating contains hypromellose, macrogol 400, titanium dioxide (E171), and polysorbate 80 (E433). If you have a known lactose intolerance, consult your doctor before taking this medicine, as the tablets contain lactose.
Warnings and Precautions
Several important warnings must be considered before and during treatment with Baraclude. Discuss these carefully with your healthcare provider:
Baraclude belongs to a class of medicines (nucleoside analogues) that can cause lactic acidosis, a potentially fatal condition characterised by excessive accumulation of lactic acid in the blood. Symptoms include nausea, vomiting, abdominal pain, generalised weakness, and rapid breathing. This rare but serious side effect has been reported with fatal outcomes. Lactic acidosis occurs more frequently in women, particularly those who are significantly overweight. Your doctor will perform regular blood tests to monitor for this condition during treatment.
Kidney function: Entecavir is primarily eliminated from the body through the kidneys. If you have kidney problems (renal impairment), your doctor may need to adjust your dose or change how often you take the medication. Patients with a creatinine clearance below 50 mL/min require dose adjustments, and the dosing interval may need to be extended. Haemodialysis patients should take entecavir after their dialysis session.
Discontinuation of treatment: Do not stop taking Baraclude without consulting your doctor. When antiviral therapy for hepatitis B is discontinued, some patients experience severe worsening (flare) of their hepatitis, with rapid increases in HBV DNA and ALT levels. In patients with decompensated liver disease, this can be particularly dangerous and potentially life-threatening. When treatment with Baraclude is stopped, your doctor will monitor you closely with blood tests for several months to detect any signs of hepatitis reactivation.
HIV co-infection: If you also have HIV (human immunodeficiency virus), you must inform your doctor. You should not take Baraclude to treat your hepatitis B unless you are also receiving antiretroviral therapy for HIV. This is because entecavir has limited activity against HIV, and using it as a single agent in HIV-positive patients could select for HIV resistance mutations (specifically the M184V mutation), which would compromise the effectiveness of future antiretroviral treatment with lamivudine or emtricitabine.
Transmission risk: Taking Baraclude does not prevent you from transmitting hepatitis B to others through sexual contact or exposure to body fluids, including blood. It remains important to take appropriate precautions to prevent transmission, such as practising safe sex and not sharing needles. Vaccination is available and highly effective at protecting at-risk individuals from hepatitis B infection.
Previous nucleoside treatment: Inform your doctor if you have previously been treated for chronic hepatitis B with any nucleoside analogue, particularly lamivudine. Prior treatment history affects the choice of dose (0.5 mg versus 1 mg) and may influence the risk of developing antiviral resistance.
Pregnancy and Breastfeeding
The safety of Baraclude during pregnancy has not been established in well-controlled clinical studies. Animal reproduction studies have shown no evidence of teratogenicity, but these studies are not always predictive of human response. Baraclude should not be used during pregnancy unless the potential benefit clearly outweighs the potential risk to the foetus and only if your doctor has specifically recommended it. Women of childbearing potential who are taking Baraclude should use effective contraception throughout the treatment period.
It is not known whether entecavir is excreted in human breast milk, although studies in rats have shown that entecavir is present in the milk of lactating animals. Because of the potential for serious adverse effects in nursing infants, breastfeeding is not recommended during treatment with Baraclude. Discuss with your doctor the most appropriate feeding option for your infant.
For pregnant women with chronic hepatitis B who require antiviral therapy, tenofovir disoproxil fumarate (TDF) or tenofovir alafenamide (TAF) are generally preferred because they have more established safety data in pregnancy, including extensive registry data from the Antiretroviral Pregnancy Registry.
Driving and Operating Machinery
Dizziness, fatigue, and drowsiness have been reported as common side effects of Baraclude. If you experience any of these symptoms, exercise caution when driving or operating heavy machinery. Discuss any concerns with your doctor.
How Does Baraclude Interact with Other Drugs?
Quick Answer: Baraclude has relatively few drug interactions because it is primarily eliminated by the kidneys. However, medications that affect kidney function or compete for renal tubular secretion may increase entecavir blood levels and require monitoring.
Entecavir is primarily eliminated through renal excretion involving both glomerular filtration and active tubular secretion. Because of this renal elimination pathway, co-administration with drugs that reduce renal function or compete for active tubular secretion may increase serum concentrations of either entecavir or the co-administered drug. This is particularly relevant in patients who already have impaired renal function.
Unlike many other drugs, entecavir is not a substrate, inhibitor, or inducer of the cytochrome P450 (CYP450) enzyme system. This means that clinically significant drug interactions mediated through hepatic metabolism are unlikely. The following table summarises known and potential drug interactions with entecavir:
| Interacting Drug | Interaction Type | Clinical Significance | Recommendation |
|---|---|---|---|
| Nephrotoxic agents (e.g., aminoglycosides, ciclosporin, tacrolimus, NSAIDs) | Reduced renal clearance | May increase entecavir levels; increased risk of adverse effects | Monitor renal function closely; dose adjustment may be needed |
| Drugs competing for tubular secretion (e.g., cimetidine) | Competitive renal secretion | Potential increase in entecavir or co-administered drug levels | Monitor for adverse effects; adjust dose if needed |
| Lamivudine | Cross-resistance | Prior lamivudine resistance increases risk of entecavir resistance | Use 1 mg dose instead of 0.5 mg; consider alternative agents |
| Adefovir dipivoxil | Potential additive nephrotoxicity | Both drugs eliminated renally; possible increased renal risk | Monitor renal function; avoid prolonged co-administration |
| Tenofovir | Additive antiviral effect / renal risk | No significant pharmacokinetic interaction; may be combined for rescue therapy | Monitor renal function when co-administered |
Always provide your doctor or pharmacist with a complete list of all medications, supplements, and herbal products you are taking. Even over-the-counter medicines such as non-steroidal anti-inflammatory drugs (NSAIDs, e.g. ibuprofen, naproxen) can affect kidney function and potentially alter entecavir levels.
Food Interactions
In most cases, Baraclude can be taken with or without food. However, there are specific circumstances where it should be taken on an empty stomach. If you have previously been treated with lamivudine and switched to Baraclude due to inadequate response, or if you have decompensated liver disease, your doctor will instruct you to take Baraclude on an empty stomach. An empty stomach means at least 2 hours after a meal and at least 2 hours before your next meal. Food has been shown to delay the absorption of entecavir and reduce peak plasma concentrations, which may be clinically relevant in patients who require maximal drug exposure.
Children and adolescents aged 2 to under 18 years may take Baraclude with or without food regardless of their treatment history.
What Is the Correct Dosage of Baraclude?
Quick Answer: The standard adult dose of Baraclude is 0.5 mg once daily for treatment-naive patients and 1 mg once daily for lamivudine-resistant patients. Dose adjustments are required for patients with impaired kidney function.
Baraclude should always be taken exactly as prescribed by your doctor. The dose depends on your treatment history, kidney function, and the status of your liver disease. Do not change your dose or stop treatment without medical advice.
Adults
| Patient Group | Recommended Dose | Frequency | Notes |
|---|---|---|---|
| Nucleoside-naive with compensated liver disease | 0.5 mg | Once daily | May be taken with or without food |
| Lamivudine-resistant / refractory with compensated disease | 1 mg | Once daily | Take on an empty stomach |
| Decompensated liver disease | 1 mg | Once daily | Take on an empty stomach; regardless of lamivudine history |
Renal Impairment Dose Adjustment
Patients with reduced kidney function (creatinine clearance < 50 mL/min) require dose adjustments. The following table outlines the recommended dosing for adults with renal impairment:
| Creatinine Clearance | Nucleoside-Naive Dose | Lamivudine-Resistant Dose |
|---|---|---|
| ≥ 50 mL/min | 0.5 mg once daily | 1 mg once daily |
| 30–49 mL/min | 0.25 mg once daily or 0.5 mg every 48 hours | 0.5 mg once daily |
| 10–29 mL/min | 0.15 mg once daily or 0.5 mg every 72 hours | 0.3 mg once daily or 0.5 mg every 48 hours |
| < 10 mL/min or haemodialysis | 0.05 mg once daily or 0.5 mg every 7 days | 0.1 mg once daily or 0.5 mg every 3 days |
Children and Adolescents (2 to < 18 Years)
The dose for children and adolescents is determined by body weight. The oral solution is recommended for patients weighing 10 kg to 32.5 kg. Children weighing 32.6 kg or more may take either the oral solution or the 0.5 mg tablet. All paediatric doses are taken once daily by mouth. There is no dosing recommendation for children under 2 years of age or weighing less than 10 kg.
Paediatric Weight-Based Dosing
Your child's doctor will calculate the appropriate dose based on body weight. The general principle is approximately 0.015 mg/kg/day for nucleoside-naive children, with a maximum dose of 0.5 mg daily. For lamivudine-experienced children, the dose is approximately 0.030 mg/kg/day, with a maximum of 1 mg daily. The oral solution provides flexible dosing at a concentration of 0.05 mg/mL.
Elderly Patients
No specific dose adjustment is required for elderly patients based solely on age. However, because renal function tends to decline with advancing age, it is important that kidney function is assessed and that dose adjustments are made according to creatinine clearance as outlined above. Your doctor will take your kidney function into account when prescribing the appropriate dose.
Missed Dose
If you forget to take a dose of Baraclude, take it as soon as you remember. However, if it is almost time for your next dose, skip the missed dose and take your next dose at the regular scheduled time. Do not take a double dose to make up for a forgotten one. Consistent daily dosing is important for maintaining adequate antiviral suppression and reducing the risk of viral resistance.
Overdose
If you have taken more Baraclude than prescribed, contact your doctor or seek emergency medical attention immediately. Limited clinical data are available on overdose with entecavir. In healthy volunteers who received single doses of up to 40 mg or multiple doses of up to 20 mg/day for 14 days, no unexpected adverse effects were observed. In case of overdose, standard supportive measures should be instituted, and the patient should be monitored for signs of toxicity. Haemodialysis removes approximately 13% of a dose of entecavir over a 4-hour session.
Some patients develop very serious hepatitis symptoms when they stop taking Baraclude. Inform your doctor immediately if you notice any change in symptoms after stopping treatment. Your doctor will conduct regular monitoring with blood tests for several months after discontinuation to detect any hepatitis flare.
What Are the Side Effects of Baraclude?
Quick Answer: Common side effects of Baraclude include headache, fatigue, dizziness, nausea, vomiting, and diarrhea. Rare but serious side effects include lactic acidosis and severe hepatomegaly with steatosis. Report any unusual symptoms to your doctor.
Like all medicines, Baraclude can cause side effects, although not everybody gets them. Clinical trials and post-marketing surveillance have identified the following adverse effects associated with entecavir treatment. The frequency categories used below follow international conventions:
Adults
Common
Affects at least 1 in 100 patients
- Headache
- Insomnia (difficulty sleeping)
- Fatigue
- Dizziness
- Drowsiness (somnolence)
- Nausea
- Vomiting
- Diarrhoea
- Dyspepsia (indigestion, discomfort in the stomach area after meals)
- Elevated liver enzyme levels (ALT) in blood tests
Uncommon
Affects at least 1 in 1,000 patients
- Skin rash
- Hair loss (alopecia)
Rare
Affects at least 1 in 10,000 patients
- Severe allergic reactions (anaphylaxis)
- Lactic acidosis (excess lactic acid in the blood)
- Severe hepatomegaly with steatosis (enlarged fatty liver)
Children and Adolescents
The side effects experienced by children and adolescents are similar to those described above for adults, with one notable addition:
Very Common
Affects at least 1 in 10 patients
- Low levels of neutrophils (neutropenia) – a type of white blood cell important for fighting infections
Neutropenia in children is generally mild to moderate and does not usually require treatment interruption, but your child's doctor will monitor blood counts regularly during therapy.
Post-Marketing Reports
Since Baraclude has been on the market, additional side effects have been identified through spontaneous reporting and post-marketing surveillance studies. These include elevated lipase and amylase levels, peripheral neuropathy, and thrombocytopenia (low platelet count). Because these events are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency.
If you experience any side effects, including any not listed here, talk to your doctor or pharmacist. You can also report suspected adverse reactions to your national pharmacovigilance authority. Reporting helps to continuously monitor the benefit–risk balance of medicines.
How Should You Store Baraclude?
Quick Answer: Store Baraclude tablets in their original packaging at room temperature. Blister packs should be kept below 30°C and bottles below 25°C. Keep out of reach of children and do not use after the expiry date.
Proper storage of medication is essential to ensure its effectiveness and safety. Follow these guidelines for storing Baraclude:
- Blister packs: Store at a temperature not exceeding 30°C. Keep the tablets in their original blister packaging until you are ready to take them. This protects them from moisture and light degradation.
- Bottles: Store at a temperature not exceeding 25°C. Keep the bottle tightly closed when not in use to prevent moisture from affecting the tablets.
- Oral solution: If using the liquid formulation, store at room temperature (up to 25°C). Do not freeze. The oral solution should be used within the timeframe specified on the label after first opening.
- Keep this medicine out of the sight and reach of children at all times.
- Do not use Baraclude after the expiry date printed on the blister, bottle, or carton (after “EXP”). The expiry date refers to the last day of the stated month.
- Do not dispose of medicines via household waste or wastewater. Ask your pharmacist how to safely dispose of medicines that are no longer needed. These measures help protect the environment.
What Does Baraclude Contain?
Quick Answer: Each Baraclude 0.5 mg tablet contains entecavir as the active ingredient, with lactose monohydrate, microcrystalline cellulose, and other excipients. The tablets are white to off-white, triangular-shaped, and marked with “BMS” on one side and “1611” on the other.
Active Substance
Each film-coated tablet contains 0.5 mg of entecavir (as entecavir monohydrate). Entecavir is a white to off-white powder with the molecular formula C12H15N5O3·H2O and a molecular weight of 295.3 (monohydrate). It is slightly soluble in water and has a specific optical rotation.
Inactive Ingredients (Excipients)
Tablet core: Crospovidone, lactose monohydrate, magnesium stearate, microcrystalline cellulose, and povidone.
Film coating: Hypromellose, macrogol 400, titanium dioxide (E171), and polysorbate 80 (E433).
Appearance and Pack Sizes
Baraclude 0.5 mg film-coated tablets are white to off-white and triangular in shape. They are debossed with “BMS” on one side and “1611” on the other side. The tablets are available in unit-dose blister packs of 30 × 1 or 90 × 1 tablets, and in bottles of 30 tablets. Not all pack sizes may be marketed in every country.
Marketing Authorisation Holder
The marketing authorisation holder is Bristol-Myers Squibb Pharma EEIG, Plaza 254, Blanchardstown Corporate Park 2, Dublin 15, D15 T867, Ireland. Baraclude is also available as a generic medication under the name Entecavir Sandoz and other brand names in various countries worldwide.
Frequently Asked Questions About Baraclude
Baraclude (entecavir) is a prescription antiviral medication used to treat chronic hepatitis B virus (HBV) infection. It is approved for use in adults and children aged 2 years and older who weigh at least 10 kg. The medication works by blocking the hepatitis B virus from replicating in the body, which reduces the viral load and helps prevent further liver damage. It can be used in patients with both compensated and decompensated liver disease.
Baraclude is typically a long-term treatment. Most patients will need to continue taking it for several years. Your doctor will determine when and if it is safe to stop treatment based on criteria such as sustained viral suppression and, in HBeAg-positive patients, the achievement of HBeAg seroconversion confirmed on two separate occasions at least 12 months apart. Stopping treatment prematurely can lead to a dangerous hepatitis flare, so never discontinue Baraclude without your doctor's guidance.
The most common side effects reported in clinical trials include headache, fatigue, dizziness, drowsiness, insomnia, nausea, vomiting, diarrhoea, dyspepsia, and elevated liver enzymes. These are generally mild and often resolve on their own during continued treatment. In children, low neutrophil counts (a type of white blood cell) are very common. Rare but serious side effects include lactic acidosis and severe hepatomegaly. Contact your doctor if you experience unusual symptoms.
No, Baraclude does not cure hepatitis B. It suppresses the virus to very low or undetectable levels, which helps prevent progressive liver damage and reduces the risk of complications such as cirrhosis and hepatocellular carcinoma. The hepatitis B virus persists in the liver cells as covalently closed circular DNA (cccDNA), which current antiviral therapies cannot eliminate. Therefore, long-term or even lifelong treatment may be necessary to keep the virus under control.
The safety of Baraclude during pregnancy has not been established through controlled human studies. It should only be used during pregnancy if the potential benefit outweighs the risk, and only on your doctor's specific recommendation. Women of childbearing age should use effective contraception while taking Baraclude. For pregnant women who need antiviral therapy for hepatitis B, tenofovir is generally the preferred option as it has a more established safety profile in pregnancy based on extensive registry data.
Stopping Baraclude suddenly can cause a severe hepatitis flare, characterised by a rapid increase in HBV DNA levels and a sharp rise in liver enzymes (ALT). This reactivation can lead to significant liver inflammation and, in patients with advanced liver disease, may result in hepatic decompensation or even liver failure. After stopping treatment, your doctor will monitor your liver function closely with blood tests every few weeks for at least 6 months to detect and manage any reactivation promptly.
References
- European Medicines Agency (EMA). Baraclude (entecavir) – Summary of Product Characteristics. EMA EPAR: Baraclude. Last updated 2025.
- World Health Organization (WHO). Guidelines for the prevention, diagnosis, care and treatment for people with chronic hepatitis B infection. Geneva: WHO; 2024. WHO HBV Guidelines 2024.
- European Association for the Study of the Liver (EASL). EASL 2017 Clinical Practice Guidelines on the management of hepatitis B virus infection. Journal of Hepatology. 2017;67(2):370–398. doi:10.1016/j.jhep.2017.03.021.
- Terrault NA, Lok ASF, McMahon BJ, et al. Update on prevention, diagnosis, and treatment of chronic hepatitis B: AASLD 2018 hepatitis B guidance. Hepatology. 2018;67(4):1560–1599. doi:10.1002/hep.29800.
- Chang TT, Lai CL, Kew Yoon S, et al. Entecavir treatment for up to 5 years in patients with hepatitis B e antigen-positive chronic hepatitis B. Hepatology. 2010;51(2):422–430. doi:10.1002/hep.23327.
- Tenney DJ, Rose RE, Baldick CJ, et al. Long-term monitoring shows hepatitis B virus resistance to entecavir in nucleoside-naïve patients is rare through 5 years of therapy. Hepatology. 2009;49(5):1503–1514. doi:10.1002/hep.22841.
- Marcellin P, Gane E, Buti M, et al. Regression of cirrhosis during treatment with tenofovir disoproxil fumarate for chronic hepatitis B: a 5-year open-label follow-up study. Lancet. 2013;381(9865):468–475. doi:10.1016/S0140-6736(12)61425-1.
- British National Formulary (BNF). Entecavir. National Institute for Health and Care Excellence (NICE). BNF: Entecavir. Accessed February 2026.
Medical Editorial Team
This article was written and reviewed by iMedic's medical editorial team, which includes board-certified specialists in hepatology, infectious disease, and clinical pharmacology.
iMedic Medical Editorial Team – Specialists in Hepatology and Infectious Disease with documented academic background and clinical experience in viral hepatitis management.
iMedic Medical Review Board – Independent panel of medical experts who review all content according to international guidelines (WHO, EMA, EASL, AASLD).
Evidence standard: All medical claims are based on Level 1A evidence from systematic reviews and meta-analyses of randomised controlled trials, supplemented by current international clinical practice guidelines. This content follows the GRADE evidence framework and is free from commercial funding or pharmaceutical industry influence.