What is Adefovir?

Adefovir is an antiviral medication. It works by preventing viral cells from multiplying in the body and infecting new liver cells.

Adefovir is used to treat chronic hepatitis B in adults. This medicine will not cure hepatitis.

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

What should I discuss with my healthcare provider before taking Adefovir?

Do not use this medication if you are allergic to adefovir.

Before taking adefovir, tell your doctor if you are allergic to any drugs, or if you have kidney or liver disease.

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.

This medication may cause lactic acidosis (the build up of lactic acid in the body). Lactic acidosis can start slowly and gradually get worse. Symptoms include unusual muscle pain and weakness, trouble breathing, fast or uneven heart rate, nausea, vomiting, stomach pain, and numbness or cold feeling in your arms or legs. Contact your doctor at once if you have any of these symptoms, even if they are only mild. Early signs of lactic acidosis generally get worse over time and this condition can be fatal.

FDA pregnancy category C. This medication may be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment.

Your name may need to be listed on an antiviral pregnancy registry if you are pregnant while using this medication. The purpose of this registry is to track the outcome of the pregnancy and delivery to evaluate whether adefovir had any effect on the baby.

It is not known whether adefovir passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

Adefovir Side Effects

What are the possible side effects of Adefovir?

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

Call your doctor at once if you have any of these serious side effects:

• urinating less than usual or not at all
• muscle pain, tenderness, or weakness (may occur several weeks or months after you start taking adefovir)
• numbness or cold feeling in your arms and legs, trouble breathing, nausea with vomiting, fast or uneven heart rate, and feeling light-headed or fainting; or
• nausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes)

Less serious side effects may include:

• mild nausea, vomiting, diarrhea, gas, or stomach pain
• mild skin rash or itching
• weakness; or
• headache

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect. You may report side effects to FDA at 1-800-FDA-1088.

Adefovir Interactions

What other drugs affect Adefovir?

Before taking adefovir, tell your doctor if you are using any of the following drugs:

• amphotericin B (Fungizone, AmBisome, Amphotec, Abelcet)
• pentamidine (Nebupent, Pentam)
• antibiotics such as capreomycin (Capastat), rifampin (Rifadin, Rimactane, Rifater), vancomycin (Vancocin, Vancoled)
• antiviral medicines such as acyclovir (Zovirax), cidofovir (Vistide), or foscarnet (Foscavir)
• cancer medicine such as aldesleukin (Proleukin), carmustine (BiCNU, Gliadel), cisplatin (Platinol), ifosfamide (Ifex), oxaliplatin (Eloxatin), plicamycin (Mithracin), streptozocin (Zanosar), or tretinoin (Vesanoid)
• medicines used to prevent organ transplant rejection, such as cyclosporine (Gengraf, Neoral, Sandimmune), sirolimus (Rapamune) or tacrolimus (Prograf)
• pain or arthritis medicines such as aspirin (Anacin, Excedrin), acetaminophen (Tylenol), diclofenac (Cataflam, Voltaren), etodolac (Lodine), ibuprofen (Advil, Motrin), indomethacin (Indocin), naproxen (Aleve, Naprosyn), and others; or
• HIV medicines such as abacavir (Ziagen), didanosine (Videx), efavirenz (Sustiva), emtricitabine (Emtriva), lamivudine (Epivir), stavudine (Zerit), tenofovir (Viread), zalcitabine (Hivid), zidovudine (Retrovir), or combinations such as Atripla, Combivir, Epzicom, Trizivir, or Truvada

This list is not complete and there may be other drugs that can interact with adefovir. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.

What should I avoid while taking Adefovir?

Avoid having unprotected sex or sharing needles, razors, or toothbrushes. Taking this medication will not prevent you from passing hepatitis B to other people. Talk with your doctor about safe methods of preventing hepatitis transmission during sex. Sharing drug or medicine needles is never safe, even for a healthy person.

Adefovir Dosage

How should I take Adefovir?

Take this medication exactly as it was prescribed for you. Do not take the medication in larger amounts, or take it for longer than recommended by your doctor. Follow the directions on your prescription label.

Take adefovir with a full glass of water.

Adefovir may be taken with or without food.

It is important to use adefovir regularly to get the most benefit. Get your prescription refilled before you run out of medicine completely.

To be sure this medication is not causing harmful effects, your blood will need to be tested on a regular basis. Your kidney or liver function may also need to be tested.

Your liver symptoms may become severe after you stop taking adefovir, even months after stopping. Your doctor may want to check your liver function on a regular basis for several months after you stop using adefovir. Do not miss any scheduled visits to your doctor.

If your condition worsens after you stop taking adefovir, your doctor may recommend that you restart this medication or another treatment for hepatitis B.

While taking adefovir, you should remain under the care of a doctor.

Store adefovir at room temperature away from moisture and heat.

What happens if I overdose on Adefovir?

Seek emergency medical attention if you think you have used too much of this medicine.

Overdose symptoms may include nausea, vomiting, diarrhea, and other stomach problems.

What happens if I miss a dose of Adefovir?

Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and take the medicine at your next regularly scheduled time. Do not take extra medicine to make up the missed dose.

Edited from everydayhealth.com