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 leucovorin, the following should be considered:

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

Pregnancy—Studies on effects in pregnancy have not been done in either humans or animals.

Breast-feeding—It is not known whether leucovorin passes into the breast milk. However, it has not been reported to cause problems in nursing babies.

Children—In children with seizures, leucovorin may increase the number of seizures that occur.

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 or if they cause different side effects or problems in older people. There is no specific information comparing use of leucovorin in the elderly with use in other age groups.

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. 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 leucovorin. If you are taking leucovorin as an antidote to methotrexate, make sure you tell your doctor if you have any other medical problems, especially:

• Kidney disease—Levels of methotrexate may be increased because of its slower removal from the body, so the dose of leucovorin may not be enough to block the unwanted effects of methotrexate

• Nausea and vomiting—Not enough leucovorin may be absorbed into the body to block the unwanted effects of methotrexate