Nucleoside reverse transcriptase inhibitors (NRTIs) for chronic hepatitis B

Examples

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Brand Name	Chemical Name
Hepsera	adefovir

Brand Name	Chemical Name
Baraclude	entecavir

Brand Name	Chemical Name
Epivir-HBV	lamivudine

How It Works

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Nucleoside reverse transcriptase inhibitors (NRTIs) are medicines that slow the ability of the hepatitis B virus (HBV) to multiply in the body. They are taken as pills once a day for at least a year, and sometimes much longer. Entecavir is also available as a liquid that you swallow.

Adefovir and entecavir are approved by the U.S. Food and Drug Administration (FDA) for use in adults. Lamivudine is approved for use in adults and for use in children ages 2 to 17.

Why It Is Used

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NRTIs are used to treat long-term (chronic) HBV infection in adults and children who are at risk for liver disease. The American Association for the Study of Liver Disease has made recommendations on who should receive treatment for chronic hepatitis B based on the presence of hepatitis B antigens in your blood, the level of hepatitis B virus DNA (HBV DNA) in your blood, and the levels of your liver enzymes.¹

How Well It Works

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Treatment for HBV infection is considered successful if blood tests show that the virus is no longer multiplying in the body, if liver enzyme levels return to normal, and if liver damage (such as inflammation and scarring) improves. NRTIs may work in more than half of people who take them, but relapse (the virus starts to multiply again) is common after a medicine is stopped, so you may have to take the medicine for a long time.^{1, 2}

Side Effects

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NRTIs rarely have side effects. If you have any side effects, they may include:

• Fever.
• Feeling tired or weak.
• Headache.
• Sore throat.
• Diarrhea.
• Dizziness.
• Pain in your belly or back.

Adefovir may harm your kidneys if you are at risk for or have a kidney problem.

In rare cases, NRTIs have led to a buildup of acid in the blood or severe liver problems. Call your doctor if you develop any symptoms of these problems such as:

• Unusual muscle pain.
• Belly pain.
• Nausea.
• Feeling cold.
• Dizziness.
• A fast heartbeat.
• Yellowing of your skin or the whites of your eyes.
• Light-colored stools.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

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• It is important to talk to your doctor about all the medicines and herbal remedies you are taking. These may affect how well your medicine for chronic hepatitis B works.
• After treatment with any type of NRTI is stopped, your infection may come back (relapse), and you may need to start taking your medicine again.
• Lamivudine was the first NRTI approved to treat chronic hepatitis B. It is safe for people who have significant cirrhosis or who have a weakened immune system from another health problem.
• Lamivudine costs less than adefovir and entecavir. Lamivudine is also cheaper than interferons, but you may end up taking it for a longer time than if you were taking interferons.
• There have been some studies combining peginterferon with lamivudine. The studies have had different results about how well combining these medicines works compared to using only one medicine.^{3, 4}
• Lamivudine should be used for at least 1 year. If lamivudine is used for a long time, the hepatitis B virus may become resistant and no longer respond to the medicine. If you develop resistance to lamivudine, you can take adefovir.
• Adefovir was approved by the U.S. Food and Drug Administration (FDA) in 2002, and entecavir was approved in 2005, so experts do not yet know the long-term effects of these medicines or how long they should be used. A recent study showed that treatment with adefovir worked better for some people with chronic hepatitis B if the medicine was taken for 144 weeks than if it was taken for only 48 weeks.⁵ After taking adefovir for a long time, you can develop resistance to the medicine, but this is much less common than with lamivudine.
• Adefovir may affect how well medicines for HIV work.
• Early studies of entecavir show that it may work better than lamivudine or adefovir.^{6, 7}
• Experts do not know if NRTIs are safe for pregnant women. They are not considered safe for women who are breast-feeding.

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.

References

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Citations

1. Lok ASF, McMahon BJ (2004). Chronic hepatitis B: Update of recommendations. Hepatology, 39(3): 857–61.

2. Hadziyannis SJ, et al. (2003). Adefovir dipivoxil for the treatment of hepatitis B e antigen-negative chronic hepatitis B. New England Journal of Medicine, 348(9): 800–807.

3. Chan HLY, et al. (2005). A randomized, controlled trial of combination therapy for chronic hepatitis B: Comparing pegylated interferon alfa-2b and lamivudine with lamivudine alone. Annals of Internal Medicine, 142(4): 240–250.

4. Janssen, H (2005). Pegylated interferon alfa-2b alone or in combination with lamivudine for HBeAg-positive chronic hepatitis B: A randomised trial. Lancet, 365(9454): 123–129.

5. Hadziyannis, SJ, et al. (2005). Long-term therapy with adefovir dipivoxil for HBeAg-negative chronic hepatitis B. New England Journal of Medicine, 352(26): 2673–2681.

6. Lai CL, et al. (2002) Entecavir is superior to lamivudine in reducing hepatitis B virus DNA in patients with chronic hepatitis B infection. Gastroenterology, 123(6): 2135–2140.

7. de Man RA, et. al. (2001) Safety and efficacy of oral entecavir given for 28 days in patients with chronic hepatitis B virus infection. Hepatology, 34(3): 578–82.

Credits

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Author	Colleen Cronin
Editor	Susan Van Houten, RN, BSN, MBA
Associate Editor	Michele Cronen
Associate Editor	Lisa Shaw
Associate Editor	Pat Truman
Primary Medical Reviewer	Kathleen Romito, MD - Family Medicine
Specialist Medical Reviewer	W. Thomas London, MD - Hepatology
Last Updated	November 4, 2005