Leucovorin Oral, Intravenous, Injection

Leucovorin is used as an antidote to the harmful effects of methotrexate (a cancer medicine) that is given in high doses. It is used also to prevent or treat certain kinds of anemia. Leucovorin acts the same way in the body as folic acid, which may be low in these patients.

Leucovorin is also used along with fluorouracil (a cancer medicine) to treat cancer of the colon (bowel).

Leucovorin is available only with a prescription.

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 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

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

Geriatric

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.

Pregnancy

Breast Feeding

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.

Interactions with 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 leucovorin, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using leucovorin with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Sulfamethoxazole
• Trimethoprim

Using leucovorin with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Capecitabine
• Doxifluridine
• Fluorouracil
• Glucarpidase
• Phenobarbital
• Primidone
• Tegafur

Interactions with Food/Tobacco/Alcohol

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 leucovorin. 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

It is very important that you take leucovorin exactly as directed , especially when it is being taken to counteract the harmful effects of cancer medicine. Do not miss any doses. Also, it is best to take the doses at evenly spaced times day and night. For example, if you are to take 4 doses a day, the doses should be spaced about 6 hours apart. If this interferes with your sleep or other daily activities, or if you need help in planning the best times to take your medicine, check with your health care professional.

Do not stop taking leucovorin without checking with your doctor. It is very important that you get exactly the right amount.

Dosing

The dose of leucovorin 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 leucovorin. 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 use as an antidote to methotrexate:
  • For oral (tablets) or injection dosage forms:
    • Adults, teenagers, and children—Dose is based on body size and must be determined by your doctor.
• For use as an antidote to other medicines:
  • For oral (tablets) or injection dosage forms:
    • Adults, teenagers, and children—Dose may range from 0.4 milligrams (mg) to 15 mg a day and must be determined by your doctor.
• For certain kinds of anemia:
  • For oral (tablets) or injection dosage forms:
    • Adults, teenagers, and children—Up to 1 mg a day.
• For colon cancer:
  • For injection dosage forms:
    • Adults and teenagers—Dose is based on body size and must be determined by your doctor.
    • Children—Dose must be determined by your doctor.

Missed Dose

Call your doctor or pharmacist for instructions.

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.

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:

• Skin rash, hives, or itching
• wheezing

Check with your doctor as soon as possible if any of the following side effects occur:

• Convulsions (seizures)

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.