This medication should be used with increased caution if you have kidney problems. Flucytosine may cause decreased kidney function and liver problems. In addition, this medication may decrease bone marrow function. This serious, possibly life-threatening side effect may lead to a low number of blood cells such as red cells, white cells, and platelets. This effect can cause anemia, decrease your body's ability to fight an infection, and cause bleeding problems. Your doctor will check the results of your kidney, liver, and blood tests and adjust your treatment to reduce your risk for these side effects. See also Side Effects section.Who should not take flucytosine?
Flucytosine is used to treat serious fungal infections in the body. It belongs to a class of drugs known as antifungal drugs. It is often used with other medications. It works by slowing the growth of certain types of fungus.
Take this medication by mouth, usually 4 times a day (every 6 hours), or as directed by your doctor. To reduce stomach upset, do not swallow all of the capsules for one dose at the same time. It may be best to swallow the capsules for each dose over a 15-minute period until the full dose is taken.
The dosage is based on your medical condition, weight, and response to treatment.
This medication works best when the amount of drug in your body is kept at a constant level. Therefore, take this drug at evenly spaced intervals. To help you remember, take it at the same times each day.
Continue to take this medication until the full prescribed amount is finished, even if symptoms disappear after a few days. Stopping the medication too early may allow the fungus to continue to grow, which may result in a return of the infection.
Tell your doctor right away if your condition persists or worsens.
Nausea, vomiting, or diarrhea may occur. See the How to Use section about how to reduce stomach upset. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor right away if any of these unlikely but serious side effects occur: change in the amount of urine, signs of liver problems (such as persistent nausea/vomiting, stomach/abdominal pain, dark urine, yellowing eyes/skin), signs of anemia (such as unusual tiredness, fast breathing, pale skin, fast heartbeat), signs of infection (such as fever, chills, cough, persistent sore throat), signs of bleeding (such as easy bruising/bleeding, nose bleeds, bleeding gums, bloody/black/tarry stools, vomit that looks like coffee grounds), muscle weakness/cramping.
A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
In the US -
Before taking flucytosine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney problems, liver problems, decreased bone marrow function, a low number of blood cells (red or white blood cells, platelets), radiation treatment, mineral imbalance (such as low level of potassium in the blood).
Wash your hands well to prevent the spread of infection. Avoid contact with people who have infections that may spread to others (such as chickenpox, measles, flu). Consult your doctor if you have been exposed to an infection or for more details.
Do not have immunizations/vaccinations without the consent of your doctor. Avoid contact with people who have recently received live vaccines (such as flu vaccine inhaled through the nose).
To lower the chance of getting cut, bruised, or injured, use caution with sharp objects like razors and nail cutters, and avoid activities such as contact sports.
Kidney function declines as you grow older. This medication is removed by the kidneys. Therefore, older adults may be more sensitive to the side effects of this drug.
During pregnancy, this medication should be used only when clearly needed. This medication is not recommended for use during the first 3 months of pregnancy. It may harm an unborn baby. Discuss the risks and benefits with your doctor.
It is not known whether this drug passes into breast milk. It may have undesirable effects on a nursing infant. Breast-feeding while using this drug is not recommended. Consult your doctor before breast-feeding.
The effects of some drugs can change if you take other drugs or herbal products at the same time. This can increase your risk for serious side effects or may cause your medications not to work correctly. These drug interactions are possible, but do not always occur. Your doctor or pharmacist can often prevent or manage interactions by changing how you use your medications or by close monitoring.
To help your doctor and pharmacist give you the best care, be sure to tell your doctor and pharmacist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products) before starting treatment with this product. While using this product, do not start, stop, or change the dosage of any other medicines you are using without your doctor's approval.
Some products that may interact with this drug include: cytarabine, other drugs that may affect the kidneys (including NSAIDs such as ibuprofen or naproxen), other drugs that decrease bone marrow function or lower your number of blood cells or weaken the immune system (such as cancer chemotherapy, trimethoprim/sulfamethoxazole).
This medication may interfere with certain laboratory tests (including serum creatinine), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.
This document does not contain all possible drug interactions. Keep a list of all the products you use. Share this list with your doctor and pharmacist to lessen your risk for serious medication problems.
If overdose is suspected, contact a poison control center or emergency room right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.
Do not share this medication with others.
Laboratory and/or medical tests (such as kidney and liver function, blood cell counts, blood mineral levels) should be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.
If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.
Store at room temperature at 77 degrees F (25 degrees C) away from light and moisture. Brief storage between 59-86 degrees F (15-30 degrees C) is permitted. Do not store in the bathroom. Keep all medicines away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.
Information last revised October 2015. Copyright(c) 2015 First Databank, Inc.
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