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Overview: Adefovir is used to treat chronic hepatitis B infection. It works by stopping the virus from multiplying, which may help protect the liver from further damage. Common side effects include headache, weakness, nausea, and stomach pain. Contact your health care provider right away if you have yellowing of the eyes, dark-colored pee, light-colored poop, or loss of appetite. These could be signs of a serious side effect.

Uses

What is adefovir used for?

Adefovir is commonly used to treat chronic hepatitis B infection.

Adefovir may also be used for other conditions as determined by your health care provider.

How does adefovir work (mechanism of action)?

Adefovir works by shutting down the production of genetic material that the hepatitis B virus needs to multiply. This may help protect the liver and prevent the virus from causing further damage.

How is adefovir supplied (dosage forms)?

Brands and other names

  • Hepsera

Dosage forms and strengths

  • 10 mg oral tablets

How should I store adefovir?

Adefovir should be stored at room temperature, between 68 F and 77 F (20 C and 25 C). It can be exposed to temperatures between 59 F and 86 F (15 C and 30 C) for shorter periods of time, such as when transporting it. Store in a cool, dry place. Keep the medicine in its original container.

Side Effects

What are the most common side effects of adefovir?

The most common side effects of adefovir are listed below. Tell your health care provider if you have any of these side effects that bother you.

  • Feeling unusually weak or tired
  • Headache
  • Stomach pain
  • Nausea
  • Increased creatinine levels, which is a test that measures how well your kidneys are working

There may be other side effects of adefovir that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of adefovir?

While less common, the most serious side effects of adefovir are described below, along with what to do if they happen.

Severe Allergic Reactions. Adefovir may cause allergic reactions, which can be serious. Stop taking adefovir and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Kidney Damage. Kidney damage can happen when taking adefovir. You may be at a higher risk of kidney damage if you already have kidney problems or take certain medicines. Keep all appointments for blood tests so your health care provider can check the health of your kidneys. Call your health care provider right away if you have any of the following symptoms of kidney damage.

  • Reduced need to pee
  • Swelling in your feet, ankles, or legs
  • Weakness or unusual tiredness
  • Difficulty catching your breath or chest pain/pressure
  • Confusion
  • Nausea
  • Seizures

Lactic Acidosis. Adefovir may cause lactic acidosis (a buildup of lactic acid in your blood), which can be serious. Stop taking adefovir and get help right away if you have any of the following symptoms of lactic acidosis.

  • General ill feeling, feeling very tired or weak, or feeling cold
  • Muscle pain
  • Trouble breathing
  • Drowsiness, dizziness, or lightheadedness
  • Stomach pain, nausea, or vomiting
  • Fast or irregular heartbeat

Liver Damage. Liver damage, also called hepatotoxicity, can happen when taking adefovir. This can cause serious liver problems that can lead to death. Call your health care provider right away if you have any of the following symptoms of liver damage.

  • Nausea or vomiting
  • Stomach or belly pain
  • Fever
  • Weakness or unusual tiredness
  • Itching
  • Loss of appetite
  • Light-colored poop
  • Dark-colored urine (pee)

Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Warnings & Precautions

Who should not use adefovir?

Allergies to Ingredients. People who are allergic to any of the following should not take adefovir.

  • Adefovir
  • Hepsera
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific adefovir products they stock.

What should I know about adefovir before using it?

Do not take adefovir unless it has been prescribed to you by a health care provider. Take it as prescribed.

Do not share adefovir with other people, even if they have the same condition as you. It may harm them.

Keep adefovir out of the reach of children.

Keep all appointments with your health care provider, including for blood tests, before and during treatment with adefovir.

Stopping adefovir can cause a serious flare-up, or worsening, of your hepatitis B. Do not run out of adefovir or stop taking it without talking to your health care provider first. If you stop taking adefovir, keep all appointments for blood tests so your health care provider can check the health of your liver.

What should I tell my health care provider before using adefovir?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if adefovir is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

  • HIV
  • Kidney problems

Other Medicines and Supplements. Adefovir may interact with other medicines and supplements. Before taking adefovir, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how adefovir could affect pregnancy or harm a fetus. Tell your health care provider if you are pregnant or plan to become pregnant. Your health care provider will let you know if you should take adefovir while you are pregnant or trying to get pregnant. If you become pregnant while taking adefovir, you can sign up for the Antiretroviral Pregnancy Registry by calling 800-258-4263 or visiting www.apregistry.com. This registry collects safety information about the use of antiretroviral medicines during pregnancy.

Breastfeeding. It is not known if adefovir passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will let you know if you should take adefovir while breastfeeding.

Interactions

Does adefovir interact with foods or drinks?

There are no known interactions between adefovir and foods or drinks.

There are no known interactions between adefovir and alcohol, but heavy drinking can slow your immune response and make it harder for your body to fight infection.

Does adefovir interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are taking any other medicines that can harm your kidneys or are removed from the body by the kidneys. Ask your pharmacist or another health care provider if you are not sure.

Also make sure you discuss if you are taking any medicines that contain tenofovir, which is a medicine that may be used to treat HIV or hepatitis B.

Some other medicines may alter the blood levels of adefovir, and vice versa. Tell your health care provider about all medicines that you take or have recently taken.

This may not be a complete list of medicines that can interact with adefovir. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much adefovir?

If you or someone else has used too much adefovir, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of adefovir?

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.

Missing doses of adefovir can cause it to not work as well over time. So it is important not to miss or skip doses.