What Is Fluconazole and How Does It Work?

Fluconazole is used to treat vaginal yeast infections. It works by stopping the growth of common types of vaginal yeast (fungus). This medication belongs to a class of drugs called azole antifungals.

Fluconazole is available under the following different brand names: Diflucan.

Dosages of Fluconazole

Dosages of Fluconazole:

Adult and Pediatric Dosage Forms and Strengths

Injected solution

  • 2 mg/mL

Oral suspension

  • 10 mg/mL
  • 40 mg/mL


  • 50 mg
  • 100 mg
  • 150 mg
  • 200 mg

Dosage Considerations – Should be Given as Follows:

Oropharyngeal Candidiasis

Adult: 200 mg orally on Day 1, Then 100 mg once/day

Pediatric: 6 mg/kg orally on Day 1, Then 3 mg/kg once/day; not to exceed 600 mg/day

Dosing considerations

  • Treatment should be administered for at least 2 weeks to decrease the likelihood of relapse

Esophageal Candidiasis

Adult: 200 mg orally on Day 1, Then 100 mg once/day; doses up to 400 mg/day may be used based on the patient's response

Pediatric: 6 mg/kg orally on Day 1, THEN 3 mg/kg once/day

Doses up to 12 mg/kg/day may be used, based on the patient's response

Dosing considerations

  • Treat for a minimum of 3 weeks and at least 2 weeks following resolution of symptoms

Cryptococcal Meningitis


  • 400 mg orally on Day 1, Then 200 mg orally once/day
  • Dosage of up to 400 mg once/day may be used based on the patient's response
  • Suppression of relapse in patients with AIDS: 200 mg orally once/day


  • 12 mg/kg orally/intravenously (IV) on Day 1, THEN 6 mg/kg once/day
  • A dose of 12 mg/kg once daily may be used, based on the patient's response
  • Suppression in children with AIDS: 6 mg/kg once daily

Dosing considerations

  • Recommended duration of therapy is 10-12 weeks after the cerebrospinal fluid becomes culture negative

Prophylaxis of Candidiasis with BMT

Prevention of candidiasis incidence in patients undergoing bone marrow transplant

400 mg orally once/day

Dosing considerations

  • Patients who are anticipated to have severe granulocytopenia should start prophylaxis several days before the anticipated onset of neutropenia and continue for 7 days after the neutrophil count rises greater than 1000 cells per mm³

Vaginal Candidiasis

Uncomplicated: 150 mg orally as a single dose

Complicated: 150 mg orally every 72 hours for 3 doses

Recurrent: 150 mg orally once/day for 10-14 days followed by 150 mg once weekly for 6 months

Candida UTI/Peritonitis

50-200 mg orally once/day

Systemic Candida Infections, Pediatric

6-12 mg/kg/day orally/intravenously (IV); not to exceed 600 mg/day

Premature Neonates

26-29 weeks gestation: 6-12 mg/kg intravenously (IV)/orally

Maintenance: 3-6 mg/kg IV/orally once/day

Maintenance dose interval

  • 26-29 weeks' gestation: every 72 hours; administer every 24 hours after 2 weeks of life

Dosage Modifications

Hepatic impairment: Not studied

Renal impairment

  • Percent of recommended dose:
  • -CrCl greater than 50 mL/min: 100% of the dose
  • -CrCl up to 50 mL/min: 50% dose
  • -Regular dialysis: 100% dose after each dialysis; on non-dialysis days, reduce dose according to creatinine clearance

What Are Side Effects Associated with Using Fluconazole?

Side effects associated with use of Fluconazole, include the following:

  • Headache
  • Nausea
  • Abdominal pain
  • Diarrhea
  • Rash
  • Vomiting

Other side effects of fluconazole include:

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

What Other Drugs Interact with Fluconazole?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider or pharmacist first.

Severe interactions of fluconazole include:

Fluconazole has serious interactions with at least 84 different drugs.

Fluconazole has moderate interactions with at least 186 different drugs.

Fluconazole has mild interactions with at least 96 different drugs.

This information does not contain all possible interactions or adverse effects. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns or for more information about this medicine.

What Are Warnings and Precautions for Fluconazole ?


  • This medication contains fluconazole. Do not take Diflucan if you are allergic to fluconazole or any ingredients contained in this drug.
  • Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center immediately


  • This medication contains fluconazole
  • Do not take Diflucan if you are allergic to fluconazole or any ingredients contained in this drug

Effects of Drug Abuse

  • No information provided

Short-Term Effects

  • Syrup contains glycerol; may cause headache, stomach upset, and diarrhea
  • When driving vehicles or operating machines, it should be taken into account that dizziness or seizures may occasionally occur
  • See "What Are Side Effects Associated with Using Fluconazole ?"

Long-Term Effects

  • See "What Are Side Effects Associated with Using Fluconazole ?”


  • Hypersensitivity to other azoles
  • Use caution in pro-arrhythmic conditions and renal impairment
  • Use extreme caution or avoid in congenital long-QT patients and patients with conditions that increase QT-prolongation risk
  • Fluconazole inhibits CYP2C9, CYP2C19, and CYP3A4 isoenzymes; co-administration with drugs that are substrates if these isoenzymes may be contraindicated or warrant dosage modifications
  • Capsules contain lactose and should not be given to patients with rare hereditary problems of galactose intolerance, Lapp lactase deficiency, or glucose-galactose malabsorption
  • Powder for oral suspension contains sucrose and should not be used in patients with hereditary fructose, glucose/galactose malabsorption or sucrase-isomaltase deficiency
  • Syrup contains glycerol; may cause headache, stomach upset, and diarrhea
  • Hepatotoxicity reported with use; use with caution in patients with hepatic impairment
  • Rare exfoliative skin disorders reported; monitor closely if rash develops and discontinue if it progresses
  • When driving vehicles or operating machines, it should be taken into account that dizziness or seizures may occasionally occur
  • Candida krusei is inherently resistant
  • Convenience and efficacy of single dose oral tablet of fluconazole regimen for the treatment of vaginal yeast infections should be weighed against acceptability of higher incidence of drug related adverse events with fluconazole (26%) versus intravaginal agents (16%)

Pregnancy and Lactation

Single maternal oral dose of 150 mg for vaginal candidiasis:

  • Results of a Danish study concludes there is a possible increased risk of miscarriage; women who are pregnant or actively trying to get pregnant should ask their physician about alternative treatments
  • Spontaneous abortion between 7 and 22 weeks' gestation occurred significantly more often in women exposed to oral fluconazole than unexposed pregnancies (4.43% vs. 4.25%; hazard ratio, 1.48); fluconazole was also compared with intravaginal azole antifungals to account for confounding by candidiasis, again, the oral drug was associated with significantly increased risk for spontaneous abortion - JAMA. 2016;315(1):58-67
  • Centers for Disease Control (CDC) guidelines recommend only using topical antifungal products to treat pregnant women with vulvovaginal yeast infections, including for longer periods than usual if these infections persist or recur

All other indications:

  • A few published case reports describe a rare pattern of distinct congenital anomalies in infants exposed in-utero to high dose maternal fluconazole (400-800 mg/day) during most or all of the first trimester
  • Reported anomalies are similar to those seen in animal studies and consist of brachycephaly, abnormal facies, abnormal calvarial development, cleft palate, femoral bowing, thin ribs and long bones, arthrogryposis, and congenital heart disease
  • Fluconazole enters breast milk; use caution if breastfeeding (American Academy of Pediatrics/AAP Committee states "compatible with nursing")
Medscape. Fluconazole.

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