Adefovir

Adefovir is a prescription medication used to treat chronic infections of hepatitis B virus in people over 12 years old. Adefovir belongs to a group of drugs called nucleotide analogs, which help decrease the amount of hepatitis B virus in the body.

This medication comes in tablet form and is usually taken once a day, with or without food.

Common side effects include weakness, headache, and nausea. 

Adefovir is a prescription medicine used to treat patients at least 12 years of age with continuing (chronic) infections with active hepatitis B virus. 

This medication may be prescribed for other uses.  Ask your doctor or pharmacist for more information.

Adefovir may be found in some form under the following brand names:

• Hepsera

Serious side effects have been reported. See "Drug Precautions" section.

Common side effects include:

• weakness
• headache
• stomach pain
• nausea
• intestinal gas
• diarrhea
• indigestion
• changes in the way the kidneys work

Additional side effects in liver transplant patients with chronic hepatitis B are vomiting, rash and itching. Some patients with liver transplants also had undesirable effects on their kidneys, including failure of the kidneys.

These are not all of the possible side effects of adefovir. For more information, ask your doctor or pharmacist.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Do not take adefovir if you are already taking Atripla, Complera, Stribild, Truvada, or Viread.

Some medicines may affect how adefovir works, especially medicines that affect how your kidneys work. Adefovir can affect how your other medicines work. Your dose of adefovir and the other medicines may be changed. Do not take any other medicines while you are taking adefovir, unless your doctor has told you it is okay.

1.  Some people who stop taking adefovir get a very serious form of hepatitis. This usually happens within 12 weeks after stopping. You will need to have regular blood tests to check for liver function and hepatitis B virus levels if you stop taking adefovir.

2.  Adefovir may cause a severe kidney problem called nephrotoxicity. It usually happens in people that already have a kidney problem, but it can happen to anyone that uses adefovir. You will need to have regular blood tests to check for kidney function while you are taking adefovir.

 

3.  If you get or have HIV that isn't being treated with medicines, adefovir may increase the chances your HIV infection cannot be helped with usual HIV medicines. This can happen if you get or have HIV and don't know it, or if your HIV is not being treated while you are taking adefovir. You should get an HIV test before you start taking adefovir and anytime after that when there's a chance you were exposed to HIV.

 

4.  Some people who have taken medicines like adefovir that are called nucleoside or nucleotide analogs have developed a serious condition called lactic acidosis (build up of an acid in the blood). Lactic acidosis is a medical emergency and must be treated in the hospital. Call your doctor right away if you get any of the following signs of lactic acidosis:

• You feel very weak or tired.
• You have unusual (not normal) muscle pain.
• You have trouble breathing.
• You have stomach pain with nausea and vomiting.
• You feel cold, especially in your arms and legs.
• You feel dizzy or lightheaded.
• You have a fast or irregular heartbeat.

Some people who have taken medicines like adefovir have developed serious liver problems called hepatotoxicity, with liver enlargement (hepatomegaly) and fat in the liver (steatosis). Call your doctor right away if you get any of the following signs of liver problems.

• Your skin or the white part of your eyes turns yellow (jaundice).
• Your urine turns dark.
• Your bowel movements (stools) turn light in color.
• You don't feel like eating food for several days or longer.
• You feel sick to your stomach (nausea).
• You have lower stomach pain.

You may be more likely to get lactic acidosis or serious liver problems if you are very overweight (obese) or have been taking nucleoside analog medicines [Atripla (efavirenz plus emtricitabine plus tenofovir disoproxil fumarate), Complera (emtricitabine plus rilpivirine plus tenofovir disoproxil fumarate), Combivir (zidovudine plus lamivudine), Emtriva (emtricitabine), Epivir, Epivir-HBV (lamivudine), Epzicom (abacavir plus lamivudine), Hivid (zalcitabine), Retrovir (zidovudine), Trizivir (zidovudine plus lamivudine plus abacavir), Truvada (emtricitabine plus tenofovir disoproxil fumarate), Videx (didanosine), Viread (tenofovir disoproxil fumarate), Zerit (stavudine), and Ziagen (abacavir)] for a long time.

• Do not take adefovir if you are allergic to any of the ingredients in adefovir. 
• Do not take adefovir if you are already taking Atripla, Complera, Stribild, Truvada, or Viread.

Medications can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of adefovir, there are no specific foods that you must exclude from your diet when receiving this medication.

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

This medication falls into category C. In animal studies, pregnant animals were given this medication and had some babies born with problems. No well-controlled studies have been done in humans. Therefore, this medication may be used if the potential benefits to the mother outweigh the potential risks to the unborn child.

Take this medication exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

The dose your doctor recommends may be based on the following:

• the condition being treated
• other medical conditions you have
• other medications you are taking
• how you respond to this medication
• your kidney function

The recommended dose of adefovir is 10 mg, once daily.

If you take too much adefovir, call your healthcare provider or local Poison Control Center, or seek emergency medical attention right away.

If adefovir is administered by a healthcare provider in a medical setting, it is unlikely that an overdose will occur. However, if overdose is suspected, seek emergency medical attention.

• Adefovir will not cure your chronic hepatitis B.
• Adefovir may help lower the amount of hepatitis B virus in your body.
• Adefovir may lower the ability of the virus to multiply and infect new liver cells.
• It is not known if adefovir will reduce your chances of getting liver cancer or liver damage (cirrhosis) from chronic hepatitis B.
• It is not known how long adefovir may help your hepatitis. Sometimes viruses change in your body and medicines no longer work. This is called drug resistance.
• Adefovir does not stop you from spreading hepatitis B virus to others by sex or sharing needles. So practice safe sex and needle use.

Adefovir tablets should be stored at room temperature and should be stored in their original container.

Keep this and all medications out of the reach of children.

WARNING: SEVERE ACUTE EXACERBATIONS OF HEPATITIS, NEPHROTOXICITY, HIV RESISTANCE, LACTIC ACIDOSIS AND SEVERE HEPATOMEGALY WITH STEATOSIS

Severe acute exacerbations of hepatitis have been reported in patients who have discontinued anti-Hepatitis B therapy including adefovir. Hepatic function should be monitored closely with both clinical and laboratory follow-up for at least several months in patients who discontinue anti-Hepatitis B therapy. If appropriate, resumption of anti-Hepatitis B therapy may be warranted.

In patients at risk of or having underlying renal dysfunction, chronic administration of adefovir may result in nephrotoxicity. These patients should be monitored closely for renal function and may require dose adjustment.

HIV resistance may emerge in chronic hepatitis B patients with unrecognized or untreated Human Immunodeficiency Virus (HIV) infection treated with anti-hepatitis B therapies, such as therapy with adefovir, that may have activity against HIV.

Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogs alone or in combination with other antiretrovirals.