It is very important that your doctor check the progress of you or your child at regular visits to make sure that this medicine is working properly. Blood and urine tests may be needed to check for unwanted effects.
Using this medicine while you are pregnant can harm your unborn baby. Use an effective form of birth control to keep from getting pregnant. If you think you have become pregnant while using the medicine, tell your doctor right away.
This medicine may cause serious skin reactions, including Stevens-Johnson syndrome, toxic epidermal necrolysis, drug reaction with eosinophilia and systemic symptoms (DRESS), acute generalized exanthematous pustulosis (AGEP), or acute febrile neutrophilic dermatosis (AFND). Check with your doctor if you have a skin rash, blistering, peeling, loosening of the skin, chills, cough, diarrhea, itching, joint or muscle pain, red irritated eyes, red skin lesions, often with a purple center, sore throat, sores, ulcers, white spots in the mouth or on the lips, black, tarry stools, chest pain, or painful or difficult urination.
Check with your doctor right away if you have dark urine, clay-colored stools, stomach pain, or yellow eyes or skin. These may be symptoms of a serious liver problem.
This medicine, especially if you are receiving high doses or for a long period of time, may lower the number of platelets in your body, which are necessary for proper blood clotting. Because of this, you may bleed or get infections more easily. Talk with your doctor if you have black, tarry stools, bleeding gums, blood in urine or stools, pinpoint red spots on the skin, unusual bleeding or bruising.
This medicine may cause diarrhea, and in some cases it can be severe. It may occur 2 months or more after you stop taking this medicine. Do not take any medicine to treat diarrhea without first checking with your doctor. If you have any questions or if mild diarrhea continues or gets worse, check with your doctor.
Check with your doctor right away if you or your child have stomach cramps, bloating, watery and severe diarrhea, which may also be bloody, nausea or vomiting, or unusual tiredness or weakness. These may be symptoms of a serious intestinal infection.
This medicine may cause serious allergic reactions, including anaphylaxis, which can be life-threatening and require immediate medical attention. Check with your doctor right away if you or your child have a rash, itching, swelling of the face, tongue, and throat, trouble breathing, or chest pain after you use the medicine.
This medicine may cause electrolyte problems, including high potassium in the blood (hyperkalemia) and low sodium in the blood (hyponatremia). Tell your doctor right away if you have confusion, weakness, muscle twitching, an irregular heartbeat, numbness or tingling in the hands, feet, or lips, or trouble breathing.
This medicine may cause hypoglycemia (low blood sugar) in some patients. Check with your doctor if you have anxiety, behavior change similar to being drunk, blurred vision, cold sweats, confusion, cool pale skin, difficulty with concentrating, drowsiness, excessive hunger, headache, nausea, nervousness, rapid heartbeat, shakiness, or unusual tiredness or weakness.
Before you have any medical tests, tell the medical doctor in charge that you or your child are taking this medicine. The results of some tests may be affected by this medicine.
Patients receiving anticonvulsant treatment (medicines to prevent seizures) may be at risk for a folate (vitamin B9) deficiency, which may increase the risk for side effects. Talk with your doctor if you have concerns about this.
Do not use this medicine if you are also using dofetilide (Tikosyn®).
Do not use this medicine for Pneumocystis jiroveci pneumonia (PCP) if you are also using leucovorin. Using these medicines together may cause these medicines to not work as well for you.
Do not take other medicines unless they have been discussed with your doctor. This includes leucovorin, other prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.
