Home Drug Guide Flucytosine

Drug Guide

Generic Name

Flucytosine

Brand Names Ancobon

Classification

Therapeutic: Antifungal agent

Pharmacological: Antimetabolite

FDA Approved Indications

  • Cryptococcal meningitis in conjunction with Amphotericin B
  • Maintenance therapy for cryptococcal meningitis after initial treatment

Mechanism of Action

Flucytosine is converted by fungal cells into 5-fluorouracil, which inhibits DNA and RNA synthesis, leading to fungal cell death.

Dosage and Administration

Adult: 25 mg/kg every 6 hours, adjusted based on renal function; typically used with Amphotericin B for cryptococcal meningitis.

Pediatric: Same as adult dosing, based on weight; dosage must be carefully adjusted for renal impairment.

Geriatric: Use with caution; renal function should be assessed.

Renal Impairment: Dose adjustment recommended based on renal function, as drug accumulation can occur.

Hepatic Impairment: No specific adjustment recommended, but monitoring advised.

Pharmacokinetics

Absorption: Well absorbed orally.

Distribution: Widely distributed in body tissues, including cerebrospinal fluid.

Metabolism: Minimal hepatic metabolism.

Excretion: Primarily excreted unchanged in urine.

Half Life: approximately 3-6 hours in patients with normal renal function.

Contraindications

  • Hypersensitivity to Flucytosine.

Precautions

  • Use with caution in patients with renal impairment, history of bone marrow suppression, or hepatic dysfunction.

Adverse Reactions - Common

  • Gastrointestinal disturbances (nausea, vomiting, diarrhea) (Common)
  • Bone marrow suppression (leukopenia, thrombocytopenia, anemia) (Common)

Adverse Reactions - Serious

  • Hepatotoxicity (Rare)
  • Orofacial or systemic hypersensitivity reactions (Rare)
  • Agranulocytosis (Rare)

Drug-Drug Interactions

  • Amphotericin B (enhanced myelosuppression)
  • Radiation therapy (increased bone marrow suppression)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor renal function (BUN, serum creatinine), liver function tests, and complete blood counts regularly.

Diagnoses:

  • Risk for infection due to bone marrow suppression
  • Risk for injury related to hematologic abnormalities

Implementation: Administer with food to reduce gastrointestinal upset. Monitor for signs of toxicity and infection.

Evaluation: Evaluate blood counts, renal and hepatic function periodically to guide dosing and detect toxicities early.

Patient/Family Teaching

  • Report symptoms of rash, fever, sore throat, bleeding, or easy bruising immediately.
  • Adhere to scheduled lab tests for blood counts and liver/kidney function.
  • Use medication as prescribed—do not skip doses.
  • Maintain adequate hydration to assist renal excretion.

Special Considerations

Black Box Warnings:

  • Myelosuppression and hepatic toxicity are serious risks, especially with prolonged therapy.

Genetic Factors: No known significant genetic factors impacting use.

Lab Test Interference: Can cause false elevation of serum creatinine.

Overdose Management

Signs/Symptoms: Gastrointestinal symptoms, hematologic toxicity, hepatic dysfunction.

Treatment: Supportive care; monitor blood counts, renal and liver function; possibly use dialysis if indicated.

Storage and Handling

Storage: Store at room temperature, protected from light.

Stability: Stable under recommended conditions for shelf life specified by manufacturer.

🛡️ 5 Critical Medication Safety Tips for Nurses

1

Triple-Check High-Risk Medications

Always have another nurse verify insulin, heparin, warfarin, and chemotherapy drugs. These "high-alert" medications cause the most serious errors. Check concentration, dose calculation, and pump settings twice.

2

Know Look-Alike, Sound-Alike Drugs

Common mix-ups: hydromorphone/morphine, Celebrex/Celexa, Zyprexa/Zyrtec. Always use BOTH generic and brand names, read labels twice, and use barcode scanning when available. One wrong letter can be fatal.

3

Assess Before AND After Giving Meds

Check vitals before cardiac meds, pain levels before analgesics, and blood glucose before insulin. Always reassess within 30 minutes to evaluate effectiveness and watch for adverse reactions.

4

Watch for Drug Interactions

Common dangerous combinations: warfarin + aspirin (bleeding), ACE inhibitors + potassium (hyperkalemia), digoxin + diuretics (toxicity). Always check drug interactions before administering new medications.

5

Educate Your Patients

Teach patients medication names, purposes, major side effects, and what to report. Informed patients catch errors and improve compliance. Always encourage questions - an educated patient is a safer patient.

⚡ Remember: When in doubt, don't give it out! It's always safer to double-check than regret later.

⚠️ Medical Disclaimer

This drug guide is for educational purposes only and is NOT intended for clinical use. Always consult current prescribing information, healthcare providers, and institutional protocols before administering any medication. Do not use this information for patient care decisions.