Ancotil
flucytosine
Pharmacologic class: Fluorinated pyrimidine analog
Therapeutic class: Antifungal
Pregnancy risk category C
Action
Unclear. Thought to interfere with protein synthesis in cells of susceptible fungi after conversion to fluorouracil.
Availability
Capsules: 250 mg, 500 mg
Indications and dosages
➣ Severe fungal infections caused by susceptible strains of Candida species (including septicemia, endocarditis, urinary tract infections [UTIs]), and pulmonary infections) and Cryptococcus species (including meningitis, pulmonary infections, and UTIs)
Adults: 50 to 150 mg/kg P.O. daily in four equally divided doses q 6 hours
Dosage adjustment
• Renal impairment (glomerular filtration rate below 50 ml/minute)
Off-label uses
• Chromomycosis
Contraindications
• Hypersensitivity to drug or other antifungals
Precautions
Use cautiously in:
• renal impairment, underlying hepatic disease, bone marrow depression
• pregnant or breastfeeding patients
• children (safety not established).
Administration
• Give capsules a few at a time over 15 minutes to minimize nausea and vomiting.
• Know that drug is rarely used alone. Expect to give another antifungal or amphotericin B concurrently.
Adverse reactions
CNS: headache, dizziness, confusion, hallucinations, vertigo, psychosis, ataxia, paresthesia, parkinsonism, peripheral neuropathy
CV: chest pain, cardiac arrest
EENT: hearing loss
GI: nausea, vomiting, diarrhea, dyspepsia, ulcerative colitis, abdominal discomfort, anorexia, duodenal ulcer, hemorrhage
GU: azotemia, crystalluria, renal failure
Hematologic: eosinophilia, anemia, leukopenia, aplastic anemia, thrombocytopenia, bone marrow depression, agranulocytosis
Hepatic: jaundice
Metabolic: hypokalemia, hypoglycemia
Respiratory: dyspnea, respiratory arrest
Skin: rash, pruritus, urticaria, photosensitivity
Interactions
Drug-drug. Amphotericin B: synergistic effects, increased risk of toxicity
Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, bilirubin, gamma-glutamyltransferase: increased levels
Glucose, granulocytes, hemoglobin, platelets, potassium, white blood cells: decreased levels
Patient monitoring
• Monitor kidney and liver function test results.
• Carefully monitor blood glucose level and hematologic test results.
See Assess for serious cardiovascular, renal, respiratory, and hematologic adverse reactions.
• Evaluate electrolyte levels, particularly potassium.
• Assess for signs and symptoms of bleeding.
Patient teaching
• Advise patient to take capsules over 15-minute period to reduce GI upset.
See Instruct patient to immediately report unusual bleeding or bruising.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.
• Instruct patient to minimize GI upset by eating frequent, small servings of food and drinking adequate fluids.
• Advise female patient to inform prescriber if she is pregnant or breastfeeding.
• Tell patient he'll undergo regular blood testing during therapy.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.