Fluconazole

What is Fluconazole?

Fluconazole is an antifungal medication belonging to the azole class of drugs. It is widely prescribed to treat and prevent various fungal infections, including vaginal yeast infections, oral thrush, and systemic fungal infections. This medication is available in both oral and intravenous forms, making it versatile for treating infections of varying severity.

Uses

Fluconazole is approved for several fungal conditions:

• Vaginal candidiasis (yeast infections): Often treated with a single oral dose for uncomplicated cases
• Oropharyngeal and esophageal candidiasis: Commonly known as oral or throat thrush, particularly in immunocompromised patients
• Systemic candida infections: Serious bloodstream infections and infections affecting internal organs
• Cryptococcal meningitis: A life-threatening brain infection, often seen in patients with weakened immune systems
• Prevention of fungal infections: Used in high-risk patients undergoing chemotherapy or organ transplantation

How it works

Fluconazole works by inhibiting an enzyme called cytochrome P450 14α-demethylase, which is essential for fungal cell membrane production. By blocking this enzyme, the medication prevents fungi from synthesizing ergosterol, a crucial component of their cell walls. This disruption weakens the fungal cell membrane, ultimately leading to cell death and elimination of the infection.

Side effects

Common side effects include:

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• Nausea and vomiting
• Headache
• Diarrhea
• Abdominal pain
• Dizziness
• Skin rash
• Changes in taste
• Flatulence

Serious side effects requiring immediate medical attention:

• Liver toxicity (yellowing of skin or eyes, dark urine, severe fatigue)
• Severe skin reactions (blistering, peeling, or widespread rash)
• Heart rhythm abnormalities (irregular heartbeat, chest pain)
• Severe allergic reactions (difficulty breathing, facial swelling)
• Seizures or severe dizziness

Warnings and precautions

• Liver function monitoring: Regular liver function tests may be required during prolonged treatment, as fluconazole can cause hepatotoxicity
• Pregnancy considerations: High doses may cause birth defects; single-dose treatment for vaginal candidiasis is generally considered safer during pregnancy
• Kidney impairment: Dose adjustments are necessary for patients with reduced kidney function, as the drug is primarily eliminated through the kidneys
• Heart conditions: Caution is advised in patients with heart rhythm disorders, as fluconazole may prolong QT interval
• Elderly patients: May require dose adjustments due to age-related changes in kidney function and increased sensitivity to side effects

Interactions

Fluconazole has numerous significant drug interactions:

• Warfarin: Increases bleeding risk by enhancing anticoagulant effects
• Phenytoin: Fluconazole increases phenytoin levels, potentially causing toxicity
• Cyclosporine: May increase cyclosporine concentrations, leading to kidney toxicity
• Oral diabetes medications: Can enhance blood sugar-lowering effects, increasing hypoglycemia risk
• Statins (simvastatin, atorvastatin): Increases statin levels, raising risk of muscle toxicity
• Benzodiazepines: May prolong sedative effects of certain benzodiazepines
• Tacrolimus: Increases immunosuppressant levels, potentially causing toxicity
• Rifampin: Decreases fluconazole effectiveness by increasing its metabolism

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Dosage

Dosage varies significantly based on the type and severity of infection:

• Vaginal candidiasis: Typically 150 mg as a single oral dose
• Oropharyngeal candidiasis: 200 mg on first day, followed by 100 mg daily for 7-14 days
• Esophageal candidiasis: 200 mg on first day, followed by 100-200 mg daily for 14-21 days
• Systemic candida infections: 400-800 mg daily, depending on severity
• Cryptococcal meningitis: 400-800 mg daily for extended periods

Treatment duration and exact dosing should always be determined by a healthcare provider based on individual patient factors, infection severity, and treatment response. Kidney function may require dose adjustments.

Sources: FDA DailyMed drug labels (public domain), BNF, WHO Essential Medicines List. This article is for informational purposes only and does not constitute medical advice. Always consult your healthcare provider before starting or stopping any medication.

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