flucytosine (Rx)

Brand and Other Names:Ancobon, 5-FC, more...5-fluorocytosine
  • Print

Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

capsule

  • 250mg
  • 500mg

Candidiasis/Cryptococcus Infection

50-150 mg/kg/d div q6hr PO  

Adjust dose for renal dysfunction

Other Indications & Uses

Off-label: chromomycosis

Dosage Forms & Strengths

capsule

  • 250mg
  • 500mg

Candidiasis/Cryptococcus Infection

Child: same as adult dosing; 50-150 mg/kg/d div q6hr PO  

Neonates (<28 days old): 80-160 mg/kg/d div q6hr PO

Adjust dose for renal dysfunction

Next:

Interactions

Interaction Checker

and flucytosine

No Results

     activity indicator 
    No Interactions Found
    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

          Minor

            All Interactions Sort By:
             activity indicator 

            Contraindicated (0)

              Serious - Use Alternative (3)

              • bacitracin

                flucytosine and bacitracin both increase nephrotoxicity and/or ototoxicity. Avoid or Use Alternate Drug. Avoid concurrent use of bacitracin with other nephrotoxic drugs

              • deferiprone

                deferiprone, flucytosine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid use of deferiprone with other drugs known to be associated with neutropenia or agranulocytosis; if an alternative is not possible, monitor absolute neutrophil count more frequently.

              • Saccharomyces boulardii

                flucytosine decreases effects of Saccharomyces boulardii by unspecified interaction mechanism. Avoid or Use Alternate Drug. Systemic or oral antifungals may decrease activity of probiotic.

              Monitor Closely (8)

              • dichlorphenamide

                dichlorphenamide and flucytosine both decrease serum potassium. Use Caution/Monitor.

              • hydroxyurea

                flucytosine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • ifosfamide

                ifosfamide, flucytosine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Ifosfamide may enhance the toxicities of myelosuppressive agents. Monitor for increased risk of myelosuppression.

              • lomustine

                lomustine, flucytosine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration may increase risk of myelosuppressive effects.

              • peramivir

                flucytosine increases levels of peramivir by decreasing renal clearance. Use Caution/Monitor. Caution when peramivir coadministered with nephrotoxic drugs.

              • tenofovir DF

                flucytosine, tenofovir DF. Either increases toxicity of the other by nephrotoxicity and/or ototoxicity. Use Caution/Monitor.

                flucytosine increases levels of tenofovir DF by decreasing renal clearance. Use Caution/Monitor.

              • tobramycin inhaled

                tobramycin inhaled and flucytosine both increase nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Avoid concurrent or sequential use to decrease risk for ototoxicity

              • voclosporin

                voclosporin, flucytosine. Either increases toxicity of the other by nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Coadministration with drugs associated with nephrotoxicity may increase the risk for acute and/or chronic nephrotoxicity.

              Minor (6)

              • amphotericin B deoxycholate

                flucytosine increases effects of amphotericin B deoxycholate by pharmacodynamic synergism. Minor/Significance Unknown.

                amphotericin B deoxycholate increases levels of flucytosine by decreasing elimination. Minor/Significance Unknown.

              • fluconazole

                flucytosine increases effects of fluconazole by pharmacodynamic synergism. Minor/Significance Unknown.

              • ganciclovir

                ganciclovir increases toxicity of flucytosine by pharmacodynamic synergism. Minor/Significance Unknown.

              • itraconazole

                flucytosine increases effects of itraconazole by pharmacodynamic synergism. Minor/Significance Unknown.

              • valganciclovir

                valganciclovir increases toxicity of flucytosine by pharmacodynamic synergism. Minor/Significance Unknown.

              • zidovudine

                zidovudine increases toxicity of flucytosine by pharmacodynamic synergism. Minor/Significance Unknown.

              Previous
              Next:

              Adverse Effects

              Frequency Not Defined

              Confusion

              Headache

              Hallucinations

              Dizziness

              Drowsiness

              Psychosis

              Parkinsonism

              Ataxia

              Sedation

              Rash

              Photosensitivity

              Pruritus

              Urticaria

              Temporary growth failure

              Hypoglycemia

              Hypokalemia

              Nausea

              Vomiting

              Diarrhea

              Abdominal pain

              Loss of appetite

              Bone marrow suppression

              Anemia

              Leukopenia

              Thrombocytopenia

              Elevated liver enzymes

              Hepatitis

              Azotemia

              Peripheral neuropathy

              Paresthesia

              Weakness

              Hearing loss

              Elevated BUN and serum creatinine

              Renal failure

              Respiratory arrest

              Anaphylaxis

              Previous
              Next:

              Warnings

              Black Box Warnings

              Use extreme caution in patients with renal impairment

              Monitor hematologic, renal, and hepatic function

              Review instructions thoroughly before administration

              Contraindications

              Hypersensitivity

              Cautions

              Bone marrow depression, renal impairment, blood dyscrasias

              Monitor to maintain blood levels <100 mg/L

              Previous
              Next:

              Pregnancy & Lactation

              Pregnancy Category: C

              Lactation: excretion in milk unknown/not recommended

              Pregnancy Categories

              A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

              B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

              C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

              D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

              X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

              NA: Information not available.

              Previous
              Next:

              Pharmacology

              Mechanism of Action

              Competitive inhibition of purine, pyrimidine uptake

              Pharmacokinetics

              Absorption: 75-90%

              Distribution: into CSF, aqueous humor, joints, peritoneal fluid, & bronchial secretions

              Protein Bound: 2-4%

              Half-life elimination: 3-8 hr; anuria: up to 200 hr; end-stage renal disease: 75-200 hr

              Peak Plasma Time: 2-6 hr

              Metabolism: minimally hepatic

              Excretion: urine (75-90% as unchanged drug)

              Previous
              Next:

              Images

              BRAND FORM. UNIT PRICE PILL IMAGE
              flucytosine oral
              -
              250 mg capsule
              flucytosine oral
              -
              500 mg capsule
              flucytosine oral
              -
              500 mg capsule
              flucytosine oral
              -
              250 mg capsule
              flucytosine oral
              -
              500 mg capsule
              flucytosine oral
              -
              250 mg capsule
              flucytosine oral
              -
              250 mg capsule
              flucytosine oral
              -
              500 mg capsule
              Ancobon oral
              -
              500 mg capsule
              Ancobon oral
              -
              250 mg capsule

              Copyright © 2010 First DataBank, Inc.

              Previous
              Next:

              Patient Handout

              Patient Education
              flucytosine oral

              FLUCYTOSINE - ORAL

              (flew-SYE-toe-seen)

              COMMON BRAND NAME(S): Ancobon

              WARNING: 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.

              USES: 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.

              HOW TO USE: 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. 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.

              SIDE EFFECTS: 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 this medication has been prescribed because your doctor 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: signs of kidney problems (such as 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.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

              PRECAUTIONS: 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 (low white, red or platelet blood counts), DPD enzyme deficiency, radiation treatment, mineral imbalance (such as low level of potassium in the blood).Flucytosine can make you more likely to get infections or may worsen any current infections. 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. 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.

              DRUG INTERACTIONS: 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.

              OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center 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.

              NOTES: 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.

              MISSED DOSE: 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. Take your next dose at the regular time. Do not double the dose to catch up.

              STORAGE: Store at room temperature away from light and moisture. 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 September 2021. Copyright(c) 2021 First Databank, Inc.

              IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.

              Previous
              Next:

              Formulary

              FormularyPatient Discounts

              Adding plans allows you to compare formulary status to other drugs in the same class.

              To view formulary information first create a list of plans. Your list will be saved and can be edited at any time.

              Adding plans allows you to:

              • View the formulary and any restrictions for each plan.
              • Manage and view all your plans together – even plans in different states.
              • Compare formulary status to other drugs in the same class.
              • Access your plan list on any device – mobile or desktop.

              The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

              Tier Description
              1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
              2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
              3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
              4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
              5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
              6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
              NC NOT COVERED – Drugs that are not covered by the plan.
              Code Definition
              PA Prior Authorization
              Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
              QL Quantity Limits
              Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
              ST Step Therapy
              Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
              OR Other Restrictions
              Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
              Additional Offers
              Email to Patient

              From:

              To:

              The recipient will receive more details and instructions to access this offer.

              By clicking send, you acknowledge that you have permission to email the recipient with this information.

              Email Forms to Patient

              From:

              To:

              The recipient will receive more details and instructions to access this offer.

              By clicking send, you acknowledge that you have permission to email the recipient with this information.

              Previous
              Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.