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Written By
P. Thirumal Reddy
B. Pharm

Reviewed By
Dr. Tejashwin Adiga
MBBS
Last updated : 24 Aug 2026 | 08:36 AM (IST)

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Quick Summary
ENTECAVIR
Last updated on 24 Aug 2026 | 08:36 AM (IST)
ENTECAVIR
Background and Date of approval ENTECAVIR
Entecavir is an antiviral medication developed by the U.S. Food And Drug Administration for treating chronic Hepatitis B with evidence of decompensated liver disease. It was initially approved on March 29, 2005, for treating chronic Hepatitis B.
Uses of ENTECAVIR
Entecavir helps to treat chronic Hepatitis B virus infection.
How is ENTECAVIR administered?
Entecavir is available in the form of a tablet and an oral solution. Take the pill on an empty stomach, at least 2 hours after and 2 hours before the next meal. The recommended Entecavir dose for adults is 0.5mg or 1mg once daily. Entecavir is not advised for use in children under two or who weigh less than 10 kg. Depending on your age, weight, and disease condition, your doctor will determine your appropriate dose and duration. Patients weighing 10kg and 32.5kg are advised to take an oral Entecavir solution. Straight from the measuring spoon, swallow it. Do not stop using this medicine unless your doctor instructs you.
Side Effects of ENTECAVIR
The side effects known to occur commonly during the treatment with Entecavir are nausea, vomiting, headache, diarrhea, insomnia (inability to sleep), fatigue (extreme tiredness), and indigestion. It might indicate lactic acidosis development if you experience stomach pain, vomiting, or nausea while taking Entecavir. This uncommon but severe side effect has occasionally been fatal.
Warnings
nform your doctor immediately if you experience allergies to Entecavir and its ingredients. Report to your doctor immediately if you have HIV/AIDS, kidney, or liver problems. You might require routine blood tests while taking Entecavir to monitor your blood counts and liver health. Avoid drinking alcohol since it could harm your liver.
Precautions
Consult your doctor before using this medication if you are pregnant or plan to have a baby. Entecavir tablets should not be taken while pregnant unless specifically advised by your doctor. Using effective contraceptive methods while using Entecavir is recommended to avoid pregnancy. Avoid breastfeeding your baby while on the treatment as it is unknown if Entecavir passes into the breastmilk.
Word of Advice
Sharing needles or other private items that might have blood or body fluids on them is not advised as it may spread HBV or HIV to other people. Regular blood tests are recommended to evaluate your liver function, hepatitis B virus level, and blood cell count. It is advised to take the hepatitis B vaccine to avoid hepatitis B infection. If you have lactose intolerance, inform your doctor before starting this therapy. Driving or using machinery should be avoided if you feel lightheaded, tired, or sleepy.
Frequently Asked Questions
Q1.
What is Entecavir used for?
Entecavir is used to treat long-term hepatitis B virus (HBV) infection in adults, children, and adolescents (2-18 years old).
Q2.
How does Entecavir work?
Entecavir works by inhibiting the DNA synthesis in the Hepatitis B virus by competing with a natural substrate (deoxyguanosine triphosphate), reducing the viral count, and improving liver conditions.
Q3.
What are the common side effects of Entecavir?
Nausea, vomiting, headache, diarrhea, insomnia (inability to sleep), fatigue (extreme tiredness), and indigestion are the common side effects of Entecavir.
Q4.
Does Entecavir cause lactic acidosis?
Entecavir may cause lactic acidosis (excess lactic acid in the blood), a rare but severe adverse effect, particularly in obese women. But if you have nausea, vomiting, or stomach pain while taking Entecavir, please get in touch with your physician immediately.
Q5.
Is Entecavir medicine safe for pregnancy?
Suppose you are pregnant or plan to get pregnant; talk to your doctor before taking Entecavir because it is unknown whether it is safe to take during pregnancy. Women of childbearing age taking Entecavir should use an effective contraception method to avoid getting pregnant.
Q6.
Can Entecavir harm the liver?
Entecavir can cause serious liver issues like steatosis and hepatomegaly (liver enlargement) (an increased build-up of fat in the liver). If you have a medical history of liver conditions, please consult your doctor, and the dose may be adjusted as needed.
Q7.
How is Entecavir taken?
Entecavir should be taken as directed by your doctor, and you should keep taking it until they advise you to stop. It is normally taken once daily on an empty stomach, at least 2 hours after and before the next meal, and it is advisable to take it every day at around the same time.
Q8.
Is Entecavir effective in treating hepatitis B virus infection?
Entecavir does not treat hepatitis B virus infection. Entecavir lowers the body's level of the hepatitis B virus and enhances liver function by reducing liver damage.
Q9.
How long should Entecavir be taken?
Avoid stopping Entecavir without first talking to your doctor. Entecavir withdrawal before treatment may make your hepatitis worse, and this may occur in the initial months after stopping Entecavir. Take the medication exactly as directed.
Q10.
Entecavir vs Tenofovir: which is more effective?
Tenofovir disoproxil fumarate (TDF) and Eentecavir (ETV) are effective antivirals that are recommended as first-line monotherapies for chronic hepatitis B (CHB) infection treatment.
References
- Goodman & Gilman’s, The Pharmacological Basics of Therapeutics, Antiviral agents (nonretroviral), 12th edition, 2011, 1616-1617.
- Accord, Electronic medicines compendium (emc), [ Revised on Feb 2019] [ Accessed on 14th April 2021], https://www.medicines.org.uk/emc/files/pil.6292.pdf
- Bristol-Myers Squibb Company, US Food and Drug Administration, [ Revised on Dec 2010] [Accessed on 19th August 2022], https://www.accessdata.fda.gov/drugsatfda_docs/label/2010/021797s011lbl.pdf
Disclaimer
The drug information on this page is not a substitute for medical advice; it is meant for educational purposes only. For further details, consult your doctor about your medical condition to know if you are eligible to receive this treatment.






