Fluconazole

Fluconazole: Complete Guide with FAQs

Introduction

• Fluconazole is an antifungal medication used to treat a wide range of fungal infections, including yeast infections, oral thrush, and systemic fungal infections.
• It belongs to the azole class of antifungals and works by inhibiting fungal cell membrane formation.
• Commonly prescribed for both superficial and systemic fungal infections.

Class and Mechanism of Action

• Class: Azole Antifungal.
• Mechanism of Action:
  • Inhibits fungal enzyme lanosterol 14-α-demethylase, preventing the synthesis of ergosterol, a key component of fungal cell membranes.
  • Disruption of the fungal cell membrane leads to cell death.

Indications

Superficial Fungal Infections

• Vaginal candidiasis (yeast infections).
• Oropharyngeal and esophageal candidiasis (oral thrush).
• Tinea infections (off-label).

Systemic Fungal Infections

• Candidemia (bloodstream infections caused by Candida).
• Cryptococcal meningitis, especially in immunocompromised patients.
• Disseminated Candida infections affecting the abdomen, kidneys, or other organs.

Prophylactic Use

• Prevention of fungal infections in immunocompromised patients (e.g., HIV/AIDS, chemotherapy, or organ transplantation).

Dosage and Administration

For Vaginal Candidiasis

• Single dose of 150 mg orally.

For Oropharyngeal Candidiasis

• 200 mg on the first day, followed by 100 mg daily for at least 7–14 days.

For Cryptococcal Meningitis

• Initial dose: 400 mg on the first day, then 200–400 mg daily for 10–12 weeks or until CSF culture is negative.

For Candidemia

• Initial dose: 800 mg on the first day, followed by 400 mg daily for 14 days after the last positive culture.

Administration Tips

• Take with or without food.
• Maintain consistent dosing intervals for best results.

Forms and Brand Names

• Forms Available: Tablets (50 mg, 100 mg, 150 mg, 200 mg), Oral Suspension, Injectable form (IV).
• Brand Names and Manufacturers:
  • Diflucan (Pfizer).
  • Generic fluconazole widely available.

Contraindications and Precautions

Contraindications

• Hypersensitivity to fluconazole or other azole antifungals.
• Concurrent use with drugs known to prolong QT interval, such as cisapride.

Precautions

• Use cautiously in patients with liver dysfunction; monitor liver function tests.
• May increase the risk of QT prolongation and arrhythmias, especially in patients with electrolyte imbalances or pre-existing heart conditions.
• Use cautiously in pregnancy; avoid high doses unless absolutely necessary.

Side Effects

Common

• Nausea or vomiting.
• Headache.
• Abdominal pain.

Less Common

• Diarrhea or constipation.
• Dizziness or fatigue.
• Skin rash.

Rare but Serious

• Hepatotoxicity (liver damage).
• Severe allergic reactions (e.g., anaphylaxis or Stevens-Johnson syndrome).
• QT prolongation leading to arrhythmias.

Drug Interactions

• Warfarin: Increased anticoagulant effect; monitor INR levels.
• Phenytoin: Increased phenytoin levels; monitor for toxicity.
• Oral Hypoglycemics (e.g., Sulfonylureas): Enhanced hypoglycemic effect; monitor blood sugar.
• Cisapride or Terfenadine: Contraindicated due to risk of QT prolongation.
• Rifampin: Decreases fluconazole levels; may require dose adjustment.

Monitoring Parameters

• Liver function tests in prolonged use.
• Renal function in patients with kidney impairment.
• Symptoms of fungal infection resolution (e.g., reduction in oral thrush, fever).

Patient Counseling Points

• Complete the full course of treatment, even if symptoms improve.
• Report symptoms like dark urine, yellowing of the skin/eyes, or severe rash immediately.
• Avoid alcohol while taking fluconazole to reduce liver strain.
• Women with recurrent vaginal yeast infections should consult a doctor for prevention strategies.
• Store tablets at room temperature and shake oral suspension well before use.

Use in Children

• Safe for use in children; doses are weight-based, typically 6–12 mg/kg daily for invasive fungal infections.

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Use in Pregnancy

• Single low-dose therapy (150 mg) is generally safe for vaginal yeast infections.
• High doses during pregnancy may increase the risk of birth defects; use only if benefits outweigh risks.

Use in Elderly

• Dose adjustments may be needed in elderly patients with kidney dysfunction.

FAQs About Fluconazole

Q1: What is fluconazole used for?

• Fluconazole treats fungal infections like vaginal yeast infections, oral thrush, and systemic fungal infections.

Q2: How quickly does fluconazole work?

• Symptom relief for superficial infections is often seen within 24–48 hours, while systemic infections may take longer.

Q3: Can fluconazole be taken with food?

• Yes, fluconazole can be taken with or without food.

Q4: Can I drink alcohol while taking fluconazole?

• Avoid alcohol, as it can increase the risk of liver side effects.

Q5: What should I do if I miss a dose?

• Take it as soon as you remember unless it’s close to the next dose. Do not double doses.

Q6: Is fluconazole safe during pregnancy?

• Low doses (e.g., 150 mg) are generally safe, but high doses should be avoided unless necessary.

Q7: How does fluconazole compare to other antifungals?

• Fluconazole is preferred for its broad spectrum of activity and oral availability but is less effective against some fungi like Aspergillus.

Q8: Can fluconazole treat athlete’s foot?

• It is not typically the first choice but may be used for resistant or severe cases.

Q9: What are the signs of fluconazole side effects?

• Watch for nausea, rash, yellowing of the skin, or severe abdominal pain.

Q10: Can fluconazole treat fungal nail infections?

• Yes, it is effective but may require prolonged treatment of several months.

Q11: Does fluconazole interact with birth control pills?

• It can occasionally reduce the effectiveness of hormonal contraceptives; consider additional protection.

Q12: Can I take fluconazole if I have liver disease?

• Use cautiously with regular liver function monitoring.

Q13: Is fluconazole available over the counter?

• In many countries, it requires a prescription, but low doses may be available OTC for vaginal yeast infections.

Q14: How long does fluconazole stay in your system?

• Its half-life is approximately 30 hours, so it may remain in the system for several days.

Q15: Can fluconazole cause resistance in fungi?

• Long-term or frequent use can lead to fungal resistance; use only as directed by a doctor.

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