Description
Adefovir is used to treat chronic (long-term) hepatitis B virus (HBV) infection in patients who are at least 12 years of age. Adefovir is not a cure for the hepatitis B virus, but it may lower the amount of virus in your body. It may also lower the ability of the virus to multiply in your body.
This medicine is available only with your doctor's prescription.
This product is available in the following dosage forms:
- Tablet
Before Using
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:
Allergies
Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Pediatric
Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of adefovir in children 12 years of age and older. Use is not recommended in children younger than 12 years of age.
Geriatric
Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of adefovir in the elderly. However, elderly patients are more likely to have age-related kidney or heart problems, which may require caution and an adjustment in the dose for patients receiving adefovir.
Breastfeeding
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.
Drug Interactions
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.
Other Interactions
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Other Medical Problems
The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:
- Human immunodeficiency virus (HIV) infection or
- Kidney disease or
- Liver disease (including cirrhosis)—Use with caution. May make these conditions worse.
Proper Use
Take this medicine exactly as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered. Also, do not stop using this medicine without checking first with your doctor.
This medicine comes with patient information leaflet. Read and follow these instructions carefully each time you get more medicine. Ask your doctor or pharmacist if you have any questions.
This medicine works best when there is a constant amount in the blood. To help keep the amount constant, do not miss any doses.
When your adefovir supply runs low, get more from your pharmacy or from your doctor. The amount of virus in your blood may increase if the medicine is stopped, even for a short time. The virus may develop resistance to adefovir and be harder to treat.
You may take this medicine with or without food.
Dosing
The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
- For oral dosage form (tablets):
- For chronic hepatitis B infection:
- Adults and children 12 years of age and older—10 milligrams (mg) once a day.
- Children younger than 12 years of age—Use is not recommended.
- For chronic hepatitis B infection:
Missed Dose
If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
Storage
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Ask your healthcare professional how you should dispose of any medicine you do not use.
Precautions
It is very important that your doctor check your progress at regular visits. This will allow your doctor to see if the medicine is working properly. Blood and urine tests may be needed to check for unwanted effects.
You should not use this medicine if you are also taking tenofovir (Viread®) or other medicines containing tenofovir (eg, Atripla®, Complera®, Stribild™, or Truvada®). Tell your doctor right away if you are using any of these medicines. Do not start using adefovir until your doctor tells you to.
If you have or get HIV infection, be sure to discuss your treatment with your doctor. If you are using this medicine to treat chronic hepatitis B, and are not taking medicine for your HIV infection at the same time, some HIV treatments may be less likely to work. You may need to get an HIV test before you start using this medicine, and again later if there is a chance you were exposed to HIV. This medicine will not help your HIV infection.
When this medicine is stopped, the liver disease (hepatitis) may become worse. Do not stop using adefovir unless your doctor tells you to. Be sure to keep all appointments with your doctor after you stop using this medicine. Blood tests will be needed to check your liver function.
Check with your doctor right away if you have more than one of the following: blood in the urine, change in frequency of urination or amount of urine, difficulty with breathing, drowsiness, increased thirst, loss of appetite, nausea or vomiting, swelling of the feet or lower legs, or weakness. These may be symptoms of a serious kidney problem.
Two rare but serious reactions to this medicine are lactic acidosis (build-up of acid in the blood) and liver toxicity, including an enlarged liver. These are more common if you are female, very overweight (obese), or have been taking anti-HIV medicines for a long time. Call your doctor right away if you have stomach discomfort or cramping, nausea, vomiting, diarrhea, decreased appetite, muscle cramping or pain, unusual tiredness or weakness, trouble breathing, or a yellowish color in your skin or eyes.
Treatment with adefovir has not been shown to decrease the chance of giving hepatitis B virus infection to other people through sexual contact or by sharing needles. If you have any questions about this, check with your doctor.
Side Effects
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
More common
- Dark urine
- general tiredness and weakness
- light-colored stools
- nausea and vomiting
- upper right abdomen or stomach pain
- yellow eyes and skin
Less common
- Blood in the urine
- change in frequency of urination or amount of urine
- difficult breathing
- drowsiness
- increased thirst
- loss of appetite
- swelling of the feet or lower legs
- weakness
Rare
- Fast, shallow breathing
- general feeling of discomfort
- muscle pain or cramping
- shortness of breath
- sleepiness
- unusual tiredness or weakness
Incidence not known
- Bloating
- bone fractures, especially of the thigh bone
- bone pain
- chills
- cloudy urine
- constipation
- convulsions
- darkened urine
- decreased frequency or amount of urine
- fast heartbeat
- fever
- increase in the amount of urine
- increased blood pressure
- indigestion
- lower back or side pain
- muscular pain, tenderness, wasting, or weakness
- pains in the stomach, side, or abdomen, possibly radiating to the back
- swelling of the face, fingers, or lower legs
- weight gain
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
More common
- Abdominal or stomach pain
- headache
- lack or loss of strength
Less common
- Acid or sour stomach
- belching
- bloated or full feeling
- diarrhea
- excess air or gas in the stomach or intestines
- heartburn
- passing gas
- stomach discomfort, upset, or pain
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
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