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 famciclovir, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to famciclovir. Also tell your health care professional if you are allergic to any other substances, such as foods, sulfites or other preservatives, or dyes.

Pregnancy—Famciclovir has not been studied in pregnant women. However, famciclovir has not been shown to cause birth defects or other problems in animal studies.

Breast-feeding—It is not known whether famciclovir passes into the breast milk of humans; however, it does pass into the milk of rats. Famciclovir is not recommended during breast-feeding because it may cause unwanted effects in nursing babies.

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

Older adults—Famciclovir has been used in the elderly and has not been shown to cause different side effects or problems in older people than it does in younger adults.

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 your dose or other precautions may be necessary. Tell your health care professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

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

• Kidney disease—Kidney disease may increase blood levels of this medicine, increasing the chance of side effects