Diflucan is the brand name for the antifungal medication fluconazole. It belongs to the class of azole antifungals and is available in pill form in strengths of 50 mg, 100 mg, 150 mg, and 200 mg. In Hong Kong, fluconazole is a prescription-only drug regulated by the Hong Kong Department of Health. The medication is used to treat a variety of fungal infections by targeting the organism’s cell membrane synthesis.
Fluconazole inhibits the fungal enzyme lanosterol 14α-demethylase, a cytochrome P450 isozyme that is essential for converting lanosterol to ergosterol, the primary sterol component of fungal cell membranes. By blocking this step, fluconazole destabilizes the membrane, leading to impaired growth and eventual death of susceptible fungi. The drug is well-absorbed after oral ingestion, with a bioavailability of ≈ 90 % and a long elimination half-life of about 30 hours, allowing once-daily dosing for many indications. Because fluconazole is primarily excreted unchanged in the urine, renal function influences drug clearance.
Fluconazole is approved by regulatory authorities, including the U.S. FDA and the Hong Kong Department of Health, for the following indications:
These uses are based on clinical trials demonstrating efficacy in clearing the infection and preventing recurrence when appropriate dosing is followed.
Some clinical guidelines discuss off-label applications of fluorozole antifungals, though they are not formally approved in Hong Kong:
These uses require careful risk-benefit assessment by a specialist. Off-label use is not approved by regulatory agencies and should only be undertaken under close medical supervision.
Ideal candidates are adults with confirmed fungal infections that are known to be susceptible to fluconazole, and who have adequate liver and kidney function to tolerate the medication.
Standard dosing varies by indication:
Vulvovaginal candidiasis: Single oral dose of 150 mg (one 150 mg tablet)
Oropharyngeal/esophageal candidiasis: 200 mg on day 1, then 100 mg daily for 7-14 days
Cryptococcal meningitis (induction): 400 mg loading dose on day 1, then 200 mg daily for at least 2 weeks, followed by maintenance 200 mg daily
Systemic candidiasis: 400 mg loading dose, then 200-400 mg daily depending on severity
Renal adjustment (CrCl < 30 mL/min): reduce daily dose by 50 % or increase dosing interval; exact regimen should be individualized.
Hepatic impairment (moderate): consider a 50 % dose reduction; severe impairment may preclude use.
Administration tips
Missed dose
Overdose
Discontinuation
This article provides educational information about Diflucan and is not a substitute for professional medical advice. Treatment decisions, including use for unapproved indications, must be made under the guidance of a qualified healthcare provider. The content is intended for informational purposes and does not constitute medical recommendations. Always consult a physician before starting, stopping, or changing any medication regimen.
Fluconazole is excreted in small amounts in breast milk. While occasional short courses are generally considered compatible with breastfeeding, prolonged high-dose therapy may increase infant exposure. Discuss the risk-benefit balance with a healthcare professional.
Fluconazole can increase plasma concentrations of certain statins that are metabolized by CYP3A4 (e.g., simvastatin, atorvastatin). Dose adjustment or selection of a statin with a lower interaction potential may be advisable.
For uncomplicated vulvovaginal candidiasis, a single 150 mg oral dose is typically sufficient to eradicate the infection, with most women experiencing symptom relief within 3-5 days.
Standard workplace drug screens do not test for fluconazole. Specialized testing would be required, but routine employment testing programs usually do not include antifungal agents.
Take the missed tablet as soon as you remember unless it is almost time for the next scheduled dose. In that case, skip the missed dose and continue with the regular dosing schedule; do not double the dose.
Antacids do not significantly affect fluconazole absorption, so they can be taken together. However, maintain consistent spacing if you experience gastrointestinal discomfort.
Fluconazole has superior oral bioavailability, a longer half-life allowing once-daily dosing, and a broader spectrum against many Candida species compared with earlier azoles like ketoconazole.
Short courses (≤ 14 days) rarely cause clinically significant liver injury. Routine monitoring is typically reserved for long-term therapy or patients with existing liver disease.
Diflucan tablets are round, white, and debossed with the strength: “50 mg” or “100 mg” on one side and “Diflucan” on the other. Higher-strength tablets (150 mg, 200 mg) may have a slight imprint indicating the dose.
Fluconazole can increase the plasma concentration of some oral hypoglycemics (e.g., sulfonylureas), potentially leading to hypoglycemia. Blood glucose should be monitored, and dose adjustments may be needed.
