Adefovir is an antiviral medicine that is used to treat chronic hepatitis B in adults and children at least 12 years old. Adefovir is not a cure for chronic hepatitis B.

Adefovir may also be used for purposes not listed in this medication guide.

You may need to be tested for HIV before you start taking adefovir. Tell your doctor if you have been exposed to HIV, or if you have untreated HIV or AIDS.

Call your doctor at once if you have liver symptoms such as right-sided upper stomach pain, nausea, loss of appetite, dark urine, or yellowing of your skin or eyes.

Adefovir can harm your kidneys, especially if you already have kidney problems or take certain medicines.

You may develop lactic acidosis, a dangerous build-up of lactic acid in your blood. Call your doctor or get emergency medical help if you have unusual muscle pain, trouble breathing, stomach pain, dizziness, feeling cold, or feeling very weak or tired.

Hepatitis B may become active or get worse after you stop using adefovir. You may need frequent liver function tests for several months.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Take the medicine at the same time each day, with or without food.

Do not change your dose or stop using adefovir without your doctor's advice.

You will need frequent medical tests.

Store at room temperature away from moisture and heat. Keep the tablets in their original container, along with the packet or canister of moisture-absorbing preservative.

Hepatitis B may become active or get worse in the months after you stop using adefovir. You may need frequent liver function tests while using this medicine and for several months after your last dose.

Usual Adult Dose for Chronic Hepatitis B:

10 mg orally once a day
Duration of therapy: Optimum duration not established

Comments:
-Indication based on histological, virological, biochemical, and serological responses in patients with hepatitis B e antigen (HBeAg)-positive and HBeAg-negative chronic hepatitis B with compensated liver function, and with clinical evidence of lamivudine-resistant HBV with compensated/decompensated liver function

Use: For the treatment of chronic HBV infection in patients with evidence of active viral replication and either evidence of persistent serum aminotransferase (ALT or AST) elevations or histologically active disease

Usual Pediatric Dose for Chronic Hepatitis B:

12 years or older: 10 mg orally once a day
Duration of therapy: Optimum duration not established

Comments:
-Indication based on virological and biochemical responses in patients with HBeAg-positive chronic HBV infection with compensated liver function

Use: For the treatment of chronic HBV infection in patients with evidence of active viral replication and either evidence of persistent serum aminotransferase (ALT or AST) elevations or histologically active disease

You should not take adefovir if you are allergic to it.

You should not take adefovir if you also medicine that contains tenofovir (Atripla, Biktarvy, Cimduo, Complera, Delstrigo, Descovy, Genvoya, Stribild, Symfi, Truvada, or Viread).

Tell your doctor if you have kidney disease or if you are on dialysis.

Tell your doctor if you have been exposed to HIV, or if you have untreated HIV or AIDS. Taking medicines to treat chronic hepatitis B can cause HIV infection to become resistant to the standard HIV and AIDS medications. You may need to be tested for HIV before you start taking adefovir.

You may develop lactic acidosis, a dangerous build-up of lactic acid in your blood. This may be more likely if you have other medical conditions, if you've taken antiviral medication for a long time, or if you are a woman. Ask your doctor about your risk.

Tell your doctor if you are pregnant or breastfeeding. If you are pregnant, your name may be listed on a pregnancy registry to track the effects of adefovir on the baby.

Adefovir is not approved for use by anyone younger than 12 years old.

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Get your prescription refilled before you run out of medicine completely.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

Unless your doctor tells you otherwise, continue your normal diet.

Using adefovir will not prevent your disease from spreading. Do not have unprotected sex or share razors or toothbrushes. Talk with your doctor about safe ways to prevent transmission during sex. Sharing drug or medicine needles is never safe, even for a healthy person.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Mild symptoms of lactic acidosis may worsen over time, and this condition can be fatal. Get emergency medical help if you have: unusual muscle pain, trouble breathing, stomach pain, vomiting, irregular heart rate, dizziness, feeling cold, or feeling very weak or tired.

Adefovir may cause serious side effects. Call your doctor at once if you have:

• kidney problems--little or no urination, swelling in your feet or ankles, feeling tired or short of breath; or

• liver problems--nausea, loss of appetite, stomach pain (upper right side), dark urine, jaundice (yellowing of the skin or eyes).

Common side effects of adefovir may include:

• stomach pain, nausea;

• weakness; or

• headache.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Adefovir can harm your kidneys, especially if you also use certain medicines for infections, cancer, osteoporosis, organ transplant rejection, bowel disorders, high blood pressure, or pain or arthritis (including Advil, Motrin, and Aleve).

Other drugs may affect adefovir, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.