Fluconazole: Uses, Dosage, Side Effects & Precautions

Fluconazole is an antifungal medicine used to treat fungal infections such as vaginal yeast infections, oral thrush and serious systemic fungal infections. This guide covers fluconazole uses, how it works, dosage, side effects, precautions, drug interactions, use in pregnancy and breastfeeding and its approximate price in India.

What is Fluconazole?

Fluconazole is an antifungal medication used to treat infections caused by fungi, including vaginal yeast infections, oral thrush, and systemic fungal infections like candidiasis.

At a Glance

How Fluconazole Works

Fluconazole works by inhibiting the synthesis of ergosterol, an essential component of fungal cell membranes. This slows fungal growth and helps the body clear the infection.

When to Use Fluconazole

• Vaginal yeast infections: Treats acute infections and, under medical guidance, helps prevent recurring ones.
• Oral thrush: Reduces fungal growth in the mouth. It is also used for thrush of the esophagus (food pipe).
• Systemic fungal infections: Treats infections caused by fungi in the bloodstream or internal organs, including cryptococcal infections such as cryptococcal meningitis.
• Prevention in high-risk patients: Used to prevent fungal infections in some people with weakened immunity, such as during chemotherapy.
• Some skin infections: Used in certain cases of tinea (ringworm, athlete’s foot) and skin candidiasis, on a doctor’s advice.

Fluconazole Dosage

The right dose depends on the type and severity of the infection. Your doctor decides the dose and how long to continue.

• Adult dose:
  • Vaginal yeast infection: 150 mg as a single dose. A longer schedule may be prescribed for recurrent infections.
  • Oral thrush: commonly 50–100 mg once daily for 7–14 days. Some regimens use a higher first-day dose.
  • Systemic infections: 200–400 mg daily, usually after a 400 mg first-day dose.
• Pediatric dose: Based on the child’s weight and the infection.
  • Systemic fungal infections: 6–12 mg/kg once daily, with a higher first-day loading dose sometimes used.
  • Mucosal infections such as thrush: usually 3 mg/kg once daily.
  • The adult maximum daily dose should not be exceeded.
  • Newborns and young infants need specialist dosing.
• Kidney problems: Fluconazole is cleared by the kidneys. The dose usually needs to be reduced when taken for several days, but a single 150 mg dose does not need adjustment.
• How to take it: With or without food. Complete the course your doctor prescribes, because stopping early can allow the infection to come back.

Take this medicine only as advised by your doctor. Do not start, stop, or change the dose on your own.

Side Effects of Fluconazole

• Common: Nausea, vomiting, abdominal pain, diarrhea, headache, rash, and raised liver enzymes on blood tests.
• Other effects: Seizures can occur occasionally, so be careful when driving or using machines.
• Contact your doctor promptly for:
  • yellowing of the skin or eyes, or other signs of liver problems (serious liver injury is rare)
  • a new rash, especially with blistering, peeling or fever (severe skin reactions are rare)
  • fast or irregular heartbeat, or fainting (fluconazole can rarely affect heart rhythm)
  • swelling of the face or throat, or trouble breathing (signs of a serious allergic reaction)

Fluconazole Precautions

Tell your doctor before taking fluconazole if you:

• have ever had an allergic reaction to fluconazole or another azole antifungal (this is a reason not to use it)
• have liver or kidney problems
• have a heart rhythm problem, heart failure or low potassium levels
• are pregnant, planning pregnancy or breastfeeding
• take other medicines

Some Candida species, such as C. krusei and C. auris, are resistant to fluconazole, so your doctor may choose a different antifungal.

Fluconazole in Pregnancy and Breastfeeding

• Pregnancy: Fluconazole should generally be avoided in pregnancy unless the infection is severe or life-threatening and the benefit outweighs the risk. There are reports of miscarriage and birth defects after use in the first trimester, including with 150 mg. A distinctive pattern of birth defects has been reported with high doses (400–800 mg daily). Women who could become pregnant should consider effective contraception during treatment and for about a week after the last dose.
• Breastfeeding: Fluconazole passes into breast milk. Breastfeeding may be maintained after a single 150 mg dose. It is not recommended after repeated or high-dose use. Talk to your doctor.

Fluconazole Drug Interactions

Fluconazole blocks liver enzymes that break down many medicines, and this effect can last 4 to 5 days after the last dose.

• Do not combine with: Cisapride, astemizole, pimozide, quinidine and erythromycin. Terfenadine is also contraindicated at fluconazole doses of 400 mg/day or more. These combinations can cause dangerous heart rhythm problems.
• Need monitoring or dose changes: Warfarin and similar blood thinners, statins such as atorvastatin and simvastatin, diabetes tablets of the sulfonylurea type, phenytoin, carbamazepine, ciclosporin, tacrolimus and some sedatives such as midazolam.
• Not recommended: Voriconazole at any dose.
• May reduce fluconazole levels:

Tell your doctor or pharmacist about all prescription medicines, OTC medicines, supplements and herbal products you take. This list is not complete.

Fluconazole Brands, Strengths and Approximate Price in India

Common Brands in India: Forcan, Zocon, Fluka. An international brand is Diflucan.

Prices vary by brand, pharmacy, location, pack size and discounts. Tablet strength is not the same as your dose, so take only what your doctor prescribes.

How HealthPil Can Help

HealthPil offers consultations with dermatologists and infectious disease specialists. Medicines should be started, adjusted, or stopped only under the guidance of a qualified healthcare professional. If you have questions about this medicine, its side effects, or your treatment plan, you can consult a doctor through HealthPil.