Adefovir

Adefovir an experimental antiviral medication that is able to inhibit enzymes necessary for Hepatitis B Virus (HBV) and HIV to reproduce.  Viruses like HIV and HBV use the genetic material in the body’s cells to produce more virus which can infect other cells.  Because adefovir may also decrease the amount of HBV found in the bloodstream, it is currently being studied as a treatment to prevent liver damage that is caused by HBV....

Why is this medication prescribed?

Adefovir is used to treat chronic (long-term) hepatitis B infection (swelling of the liver caused by a virus) in patients who have symptoms of the disease. Adefovir is in a class of medications called nucleotide analogs. It works by decreasing the amount of hepatitis B virus (HBV) in the body. Adefovir will not cure hepatitis B and may not prevent complications of chronic hepatitis B such as cirrhosis of the liver or liver cancer. Adefovir may not prevent the spread of hepatitis B to other people.

How should this medicine be used?

Adefovir comes as a tablet to take by mouth. It is usually taken once a day with or without food. Take adefovir at around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take adefovir exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Other uses for this medicine

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

What special precautions should I follow?

Before taking adefovir,

• tell your doctor and pharmacist if you are allergic to adefovir or any other medications.
• tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention the medications listed in the IMPORTANT WARNING section and probenecid. Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Do not take any other medications while you are taking adefovir unless your doctor has told you that you should.
• do not take adefovir if you are pregnant or plan to become pregnant. If you become pregnant while taking adefovir, call your doctor. Do not breast-feed while taking adefovir.
• if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking adefovir.

What special dietary instructions should I follow?

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

What should I do if I forget a dose?

If you remember the missed dose on the day that you were supposed to take it, take the missed dose as soon as you remember it. However, if you do not remember the missed dose until the next day, skip the missed dose and continue your regular dosing schedule. Do not take more than 1 dose of adefovir on the same day. Do not take a double dose to make up for a missed one.

What side effects can this medication cause?

Adefovir may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• weakness
• headache
• diarrhea
• gas
• indigestion
• cough
• sore throat
• runny nose

Some side effects can be serious. If you experience this symptom or any of those listed in the IMPORTANT WARNING section, call your doctor immediately:

• rash

Adefovir may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at http://www.fda.gov/MedWatch/report.htm] or by phone [1-800-332-1088].

What storage conditions are needed for this medicine?

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). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.

In case of emergency/overdose

In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

Symptoms of overdose may include:

• upset stomach
• stomach discomfort
• vomiting
• gas
• loose bowel movements
• loss of appetite

What other information should I know?

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

Brand names

• Hepsera®

Do not stop taking adefovir without talking to your doctor. When you stop taking adefovir your hepatitis may get worse. This is most likely to happen during the first 3 months after you stop taking adefovir. Be careful not to miss doses or run out of adefovir. Refill your prescription at least 5 days before you expect that you will need the new supply of medication. Tell your doctor if you have or have ever had liver disease other than hepatitis B or cirrhosis (scarring of the liver). If you experience any of the following symptoms after you stop taking adefovir, call your doctor immediately: extreme tiredness, weakness, upset stomach, vomiting, loss of appetite, yellowing of the skin or eyes, dark-colored urine, light-colored bowel movements, and muscle or joint pain.Adefovir may cause kidney damage. Tell your doctor if you have or have ever had kidney disease, high blood pressure, or diabetes. Tell your doctor and pharmacist if you are taking or have ever taken any of the following medications: aminoglycoside antibiotics such as amikacin (Amikin), gentamicin (Garamycin), kanamycin (Kantrex), neomycin (Neo-Rx, NeoFradin), paramomycin (Humatin), streptomycin, and tobramycin (Tobi, Nebcin); amphotericin B (Fungizone); aspirin and other non-steroidal antiinflammatory medications (NSAIDS) such as ibuprofen (Advil, Motrin) and naproxen (Aleve, Naprosyn); cyclosporine (Neoral, Samdimmune); tacrolimus (Prograf); or vancomycin. If you experience any of the following symptoms, call your doctor immediately: confusion; decreased urination; or swelling of the hands, feet, ankles, or lower legs. If you have HIV or AIDS that is not being treated with medications and you take adefovir, your HIV infection may become difficult to treat. Tell your doctor if you have HIV or AIDS or if you have unprotected sex with more than one partner or use injectable street drugs. Your doctor may test you for HIV infection before you begin treatment with adefovir and at any time during your treatment when there is a chance that you were exposed to HIV.Adefovir, when used alone or in combination with other antiviral medications, can cause serious or life-threatening damage to the liver and a condition called lactic acidosis (a build-up of acid in the blood). Tell your doctor if you drink or have ever drunk large amounts of alcohol, if you use or have ever used injectable street drugs, and if you have or have ever had any liver disease other than hepatitis B. Tell your doctor and pharmacist if you are taking or have ever taken the following medications: acetaminophen (Tylenol, others); cholesterol-lowering medications (statins); iron products; isoniazid (INH, Nydrazid); medications to treat HIV or AIDS; methotrexate (Rhuematrex); niacin (nicotinic acid); or rifampin (Rifadin, Rimactane). If you experience any of the following symptoms, call your doctor immediately: confusion; unusual bleeding or bruising; yellowing of the skin or eyes; dark-colored urine; light-colored bowel movements; difficulty breathing; stomach pain or swelling; upset stomach; vomiting; unusual muscle pain; loss of appetite for at least a few days; lack of energy; flu-like symptoms; itching; feeling cold, especially in the arms or legs; dizziness or lightheadedness; fast or irregular heart beat; or extreme weakness or tiredness.Keep all appointments with your doctor and the laboratory before, during, and for a few months after your treatment with adefovir. Your doctor will order certain lab tests to check your body's response to adefovir during this time.Talk to your doctor about the risks of taking adefovir.