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flucytosine (floo-sye-toe-seen)

Ancobon, Ancotil, 5-FC


Therapeutic: antifungals

Pharmacologic: fluorinated pyrimidine analogs


Treatment of serious fungal infections, including Endocarditis, Meningitis, Septicemia, Urinary tract infections, Pulmonary infections.


Following penetration into fungi, converted to fluorouracil, which interferes with fungal DNA and RNA synthesis. Synergistic action with amphotericin B against some fungi. Therapeutic Effects: Fungicidal action against susceptible organisms. Spectrum: Active against only a small number of fungi, mainly: Candida, Cryptococcus.

Adverse Reactions/Side Effects

CNS: SEIZURES, ataxia, confusion, dizziness, drowsiness, fatigue, headache. CV: chest pain. EENT: hearing loss. GI: diarrhea, nausea, vomiting, abdominal pain, dry mouth. Derm: photosensitivity, pruritus, rash, urticaria. Endo: hypoglycemia. F and E: hypokalemia. GU: azotemia. Hemat: APLASTIC ANEMIA, eosinophilia, leukopenia, pancytopenia, anemia, thrombocytopenia. Neuro: peripheral neuropathy. Resp: dyspnea. Misc: fever.


Examination and Evaluation

  • Be alert for new seizures or increased seizure activity, especially at the onset of drug treatment. Document the number, duration, and severity of seizures, and report these findings to the physician immediately.

  • Monitor signs of blood dyscrasias, including aplastic anemia (fatigue, pallor, shortness of breath with exertion), eosinophilia (weakness, myalgia), leukopenia (fever, sore throat, signs of infection), thrombocytopenia (bruising, nose bleeds, bleeding gums), or unusual weakness and fatigue that might be due to other anemias and blood dyscrasias. Notify physician of these signs immediately.

  • Monitor signs of peripheral neuropathy (numbness, tingling, muscle weakness). Perform objective tests (nerve conduction, monofilaments) to assess and document any neuropathic changes.

  • Assess dizziness, drowsiness, or ataxia that might affect gait, balance, and other functional activities. Report balance problems and functional limitations to the physician, and caution the patient and family/caregivers to guard against falls and trauma.

  • Monitor any chest pain or difficult, labored breathing. Attempt to determine if pain is drug induced or caused by cardiovascular and pulmonary dysfunction (e.g., angina that occurs during exercise). Report any problematic cardiorespiratory symptoms.

  • Monitor signs of hypoglycemia, including weakness, malaise, irritability, and fatigue. Patients with diabetes mellitus should check blood glucose levels frequently.

  • Monitor and report signs of low potassium levels (hypokalemia), such as muscle weakness, aches, and cramps.

  • Monitor signs of increased nitrogenous compounds in the blood (azotemia), including confusion, decreased alertness, tachycardia, pallor, fatigue, dry mouth, thirst, and decreased/absent urine production. Notify physician of these signs immediately.


  • Always wash hands thoroughly and disinfect equipment (whirlpools, electrotherapeutic devices, treatment tables, and so forth) to help prevent the spread of infection. Employ universal precautions or isolation procedures as indicated for specific patients.

  • Causes photosensitivity; use care if administering UV treatments. Advise patient to avoid direct sunlight and use sunscreens and protective clothing.

Patient/Client-Related Instruction

  • Advise patient to take ...

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