Before Using This Medicine

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 adefovir, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to adefovir. Also tell your doctor and pharmacist if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Adefovir has not been studied in pregnant women. However, studies in animals have shown that adefovir may cause birth defects or other problems. Before taking this medicine, make sure your doctor knows if you are pregnant or if you may become pregnant.

Breast-feeding—It is not known whether adefovir passes into breast milk. However, it should not be used by women who are breast-feeding because it may cause unwanted effects in nursing babies.

Children—Studies on adefovir have been done only in adult patients, and there is no specific information comparing the use of adefovir in children with use in other age groups.

Older adults—Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults. Older patients should use this medicine with caution. Elderly people can be especially sensitive to the effects of medicines.

Other medicines—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. When you are taking adefovir, it is especially important that your doctor and pharmacist know if you are taking any of the following:

• Nephrotoxic medicines (medicines that can be harmful to your kidneys), such as:
• Aminoglycosides (medicines used to treat infection) or
• Cyclosporine (e.g., Sandimmune or Neoral) or
• Non-steroidal anti-inflammatory medicines (medicines used to treat pain and inflammation) or
• Tacrolimus (e.g. Prograf) or
• Vancomycin (medicine used to treat severe infections)—Using these medicines with adefovir may cause you to have a higher chance of having problems with your kidneys.

• Nucleoside analog medicines (other antiviral medicines), such as:
• Abacavir (e.g. Ziagen) or
• Abacavir, Lamivudine, and Zidovudine (e.g. Trizivir) or
• Didanosine (e.g. Videx) or
• Lamivudine (e.g. Epivir) or
• Lamivudine and Zidovudine (e.g. Combivir) or
• Stavudine (e.g. Zerit) or
• Tenofovir (e.g. Viread) or
• Zalcitabine (e.g. Hivid) or
• Zidovudine (e.g. Retrovir)—Using these medicines with adefovir may cause you to have a higher chance of having problems with your liver or developing lactic acidosis.

Other medical problems—The presence of other medical problems may affect the use of adefovir. Make sure you tell your doctor if you have any other medical problems, especially:

• Human immunodeficiency virus (HIV)—It is important to talk to your doctor about the HIV virus before starting this medicine. Adefovir can make this condition worse.

• Kidney problems—Adefovir can cause kidney problems and your doctor may want to change your dose.