Fluconazole 50mg Tablets
It is used to treat fungal infections. It is used to prevent fungal infections.This drug is used to treat vaginal yeast infections.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Antifungal
Pharmacologic Class
Triazole Antifungal
Pregnancy Category
Category C (single dose for vaginal candidiasis); Category D (multiple/high doses for other indications)
FDA Approved
Jan 1990
DEA Schedule
Not Controlled
Overview
What is this medicine?
Fluconazole is an antifungal medication used to treat various fungal infections, including yeast infections of the mouth, throat, esophagus, and vagina, as well as more serious fungal infections in other parts of the body. It works by stopping the growth of the fungus.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication as directed, with or without food. Continue taking it even if you feel well, unless your doctor or healthcare provider advises you to stop.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, avoiding bathrooms. Keep all medications in a safe location, out of reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about disposal, consult your pharmacist. You may also want to check if there are drug take-back programs in your area.
Missing a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next dose, skip the missed dose and resume your regular schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication as directed, with or without food. Continue taking it even if you feel well, unless your doctor or healthcare provider advises you to stop.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, avoiding bathrooms. Keep all medications in a safe location, out of reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about disposal, consult your pharmacist. You may also want to check if there are drug take-back programs in your area.
Missing a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next dose, skip the missed dose and resume your regular schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
Lifestyle & Tips
- Take the medication exactly as prescribed by your doctor, even if your symptoms improve. Do not stop taking it early unless advised by your doctor.
- For vaginal yeast infections, a single dose is often sufficient. For other infections, you may need to take it for weeks or months.
- Maintain good hygiene practices to prevent recurrence of fungal infections.
- Avoid alcohol consumption, especially during prolonged treatment, as it can increase the risk of liver problems.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
50 mg once daily (e.g., for oropharyngeal candidiasis or prophylaxis)
Dose Range:
50 - 400 mg
Condition-Specific Dosing:
oropharyngealCandidiasis:
50-100 mg once daily for 7-14 days
esophagealCandidiasis:
200 mg on day 1, then 100 mg once daily for 14-30 days (up to 400 mg/day for severe cases)
vaginalCandidiasis:
150 mg as a single oral dose
systemicCandidiasis:
400 mg on day 1, then 200-400 mg once daily for several weeks (duration depends on site and severity)
cryptococcalMeningitis:
400 mg on day 1, then 200-400 mg once daily for 10-12 weeks after CSF culture is negative (maintenance: 200 mg once daily)
prophylaxisInImmunocompromised:
50-400 mg once daily, depending on risk
Pediatric Dosing
Neonatal:
Not established for routine use, but used off-label: 0-14 days: 3-6 mg/kg every 72 hours; 15-28 days: 3-6 mg/kg every 48 hours (for systemic infections)
Infant:
3-6 mg/kg once daily (for systemic infections)
Child:
3-6 mg/kg once daily (max 600 mg/day); Oropharyngeal candidiasis: 6 mg/kg on day 1, then 3 mg/kg once daily for at least 2 weeks. Esophageal candidiasis: 6 mg/kg on day 1, then 3 mg/kg once daily for at least 3 weeks and for at least 2 weeks following resolution of symptoms.
Adolescent:
Adult dosing generally applies, adjusted for weight/severity.
Dose Adjustments
Renal Impairment:
Mild:
No adjustment needed (CrCl > 50 mL/min)
Moderate:
Reduce dose by 50% after initial loading dose (CrCl 21-50 mL/min)
Severe:
Reduce dose by 50% after initial loading dose (CrCl < 20 mL/min)
Dialysis:
Administer 100% of the recommended dose after each hemodialysis session. On non-dialysis days, administer a reduced dose based on CrCl.
Hepatic Impairment:
Mild:
No specific adjustment recommended
Moderate:
No specific adjustment recommended, use with caution
Severe:
No specific adjustment recommended, use with caution and monitor LFTs closely
Pharmacology
Mechanism of Action
Fluconazole inhibits fungal cytochrome P450 enzyme 14-alpha-demethylase, which is essential for the conversion of lanosterol to ergosterol. Ergosterol is a vital component of the fungal cell membrane. Inhibition of ergosterol synthesis leads to increased cellular permeability, leakage of cellular contents, and ultimately fungal cell death.
Pharmacokinetics
Absorption:
Bioavailability:
Greater than 90%
Tmax:
0.5-1.5 hours
FoodEffect:
Absorption is not significantly affected by food.
Distribution:
Vd:
0.7-1.0 L/kg (similar to total body water)
ProteinBinding:
11-12%
CnssPenetration:
Yes (achieves concentrations in CSF approximately 50-90% of plasma concentrations)
Elimination:
HalfLife:
Approximately 30 hours (range 20-50 hours)
Clearance:
Primarily renal
ExcretionRoute:
Renal (urine)
Unchanged:
Approximately 80% of the dose is excreted unchanged in urine.
Pharmacodynamics
OnsetOfAction:
Within hours (clinical improvement typically seen within days)
PeakEffect:
Variable, depends on infection type and severity (e.g., 24-48 hours for some candidal infections)
DurationOfAction:
Due to long half-life, allows for once-daily dosing.
Safety & Warnings
Side Effects
Serious Side Effects: Seek Medical Help Right Away
Although rare, this medication can cause severe and potentially life-threatening side effects. If you experience any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of liver problems, including:
+ Dark urine
+ Tiredness
+ Decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellow skin or eyes
Signs of a weak adrenal gland, such as:
+ Severe upset stomach or vomiting
+ Severe dizziness or fainting
+ Muscle weakness
+ Feeling very tired
+ Mood changes
+ Decreased appetite
+ Weight loss
Seizures
A type of severe abnormal heartbeat (prolonged QT interval), which can lead to another type of abnormal heartbeat (torsades de pointes). This is more likely to occur in people with other serious health problems or those taking other medications that can affect heart rhythm. If you experience a fast or abnormal heartbeat, or if you pass out, contact your doctor right away.
Other Side Effects
Like all medications, this drug can cause side effects. While many people do not experience any side effects or only have mild ones, it is essential to discuss any concerns with your doctor. If you experience any of the following side effects, or if they bother you or do not go away, contact your doctor:
Dizziness or headache
Stomach pain or diarrhea
Upset stomach or vomiting
* Change in taste
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, this medication can cause severe and potentially life-threatening side effects. If you experience any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of liver problems, including:
+ Dark urine
+ Tiredness
+ Decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellow skin or eyes
Signs of a weak adrenal gland, such as:
+ Severe upset stomach or vomiting
+ Severe dizziness or fainting
+ Muscle weakness
+ Feeling very tired
+ Mood changes
+ Decreased appetite
+ Weight loss
Seizures
A type of severe abnormal heartbeat (prolonged QT interval), which can lead to another type of abnormal heartbeat (torsades de pointes). This is more likely to occur in people with other serious health problems or those taking other medications that can affect heart rhythm. If you experience a fast or abnormal heartbeat, or if you pass out, contact your doctor right away.
Other Side Effects
Like all medications, this drug can cause side effects. While many people do not experience any side effects or only have mild ones, it is essential to discuss any concerns with your doctor. If you experience any of the following side effects, or if they bother you or do not go away, contact your doctor:
Dizziness or headache
Stomach pain or diarrhea
Upset stomach or vomiting
* Change in taste
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Yellowing of the skin or eyes (jaundice)
- Dark urine or pale stools
- Unusual tiredness or weakness
- Nausea, vomiting, or loss of appetite
- Severe skin rash, blistering, or peeling skin
- Swelling of the face, lips, tongue, or throat (signs of allergic reaction)
- Difficulty breathing or swallowing
- Fast or irregular heartbeat, dizziness, or fainting
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced.
If you are currently taking any of the following medications: Abrocitinib, astemizole, cisapride, erythromycin, lemborexant, olaparib, pimozide, quinidine, terfenadine, or voriconazole.
If you are pregnant or think you might be pregnant. You will need to discuss the potential risks and benefits of this medication with your doctor to determine if it is suitable for you.
Please note that this is not an exhaustive list of all possible interactions. To ensure your safety, it is crucial to:
Inform your doctor and pharmacist about all the medications you are taking, including prescription and over-the-counter drugs, natural products, and vitamins.
Share information about your health problems, as they may affect the safety and efficacy of this medication.
Never start, stop, or change the dose of any medication without first consulting your doctor to confirm that it is safe to do so.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced.
If you are currently taking any of the following medications: Abrocitinib, astemizole, cisapride, erythromycin, lemborexant, olaparib, pimozide, quinidine, terfenadine, or voriconazole.
If you are pregnant or think you might be pregnant. You will need to discuss the potential risks and benefits of this medication with your doctor to determine if it is suitable for you.
Please note that this is not an exhaustive list of all possible interactions. To ensure your safety, it is crucial to:
Inform your doctor and pharmacist about all the medications you are taking, including prescription and over-the-counter drugs, natural products, and vitamins.
Share information about your health problems, as they may affect the safety and efficacy of this medication.
Never start, stop, or change the dose of any medication without first consulting your doctor to confirm that it is safe to do so.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
Before operating a vehicle or engaging in any activity that requires your full attention, wait until you understand how this medication affects you.
Do not exceed the prescribed duration of treatment, as this may increase the risk of a secondary infection.
Regular blood tests will be necessary, as directed by your doctor. Be sure to discuss any concerns or questions with your doctor.
Additionally, consult your doctor before consuming alcohol while taking this medication.
There is a risk of severe skin reactions, including rashes, which can be life-threatening, particularly in individuals with pre-existing health conditions. If you experience any unusual skin symptoms, promptly discuss them with your doctor.
Although rare, severe liver problems, sometimes fatal, have occurred in patients taking this medication, often in those with underlying health issues. If you have concerns, consult your doctor.
In some cases, a severe and potentially life-threatening reaction may occur, characterized by symptoms such as fever, rash, swollen glands, and organ dysfunction (affecting the liver, kidneys, blood, heart, muscles, joints, or lungs). If you have questions or concerns, discuss them with your doctor.
If you are 65 years or older, exercise caution when taking this medication, as you may be more susceptible to side effects.
For women of childbearing age, discuss birth control options with your doctor to prevent pregnancy during treatment and for a period after the last dose, as this medication may harm the unborn baby.
If you become pregnant or suspect you are pregnant while taking this medication, immediately contact your doctor.
If you are breastfeeding, inform your doctor to assess any potential risks to your baby.
Before operating a vehicle or engaging in any activity that requires your full attention, wait until you understand how this medication affects you.
Do not exceed the prescribed duration of treatment, as this may increase the risk of a secondary infection.
Regular blood tests will be necessary, as directed by your doctor. Be sure to discuss any concerns or questions with your doctor.
Additionally, consult your doctor before consuming alcohol while taking this medication.
There is a risk of severe skin reactions, including rashes, which can be life-threatening, particularly in individuals with pre-existing health conditions. If you experience any unusual skin symptoms, promptly discuss them with your doctor.
Although rare, severe liver problems, sometimes fatal, have occurred in patients taking this medication, often in those with underlying health issues. If you have concerns, consult your doctor.
In some cases, a severe and potentially life-threatening reaction may occur, characterized by symptoms such as fever, rash, swollen glands, and organ dysfunction (affecting the liver, kidneys, blood, heart, muscles, joints, or lungs). If you have questions or concerns, discuss them with your doctor.
If you are 65 years or older, exercise caution when taking this medication, as you may be more susceptible to side effects.
For women of childbearing age, discuss birth control options with your doctor to prevent pregnancy during treatment and for a period after the last dose, as this medication may harm the unborn baby.
If you become pregnant or suspect you are pregnant while taking this medication, immediately contact your doctor.
If you are breastfeeding, inform your doctor to assess any potential risks to your baby.
Overdose Information
Overdose Symptoms:
- Hallucinations
- Paranoid behavior
- Seizures
- Liver dysfunction
What to Do:
In case of overdose, seek immediate medical attention or call a poison control center. Call 1-800-222-1222. Treatment may involve symptomatic and supportive measures, and hemodialysis can significantly decrease plasma levels.
Drug Interactions
Contraindicated Interactions
- Terfenadine (with multiple dose fluconazole 400 mg/day or higher)
- Cisapride
- Pimozide
- Quinidine
- Erythromycin (risk of cardiotoxicity)
- Amiodarone (risk of Torsades de Pointes)
Major Interactions
- Warfarin (increased prothrombin time)
- Phenytoin (increased phenytoin levels)
- Cyclosporine (increased cyclosporine levels)
- Tacrolimus (increased tacrolimus levels)
- Rifampin (decreased fluconazole levels)
- Oral Hypoglycemics (sulfonylureas - increased risk of hypoglycemia)
- Statins (e.g., atorvastatin, simvastatin - increased risk of myopathy/rhabdomyolysis)
- Benzodiazepines (e.g., midazolam, triazolam - increased sedation)
- Theophylline (increased theophylline levels)
- Voriconazole (increased fluconazole and voriconazole levels)
- Hydrochlorothiazide (increased fluconazole levels)
- Fentanyl (increased fentanyl exposure)
- Ivacaftor (increased ivacaftor exposure)
Moderate Interactions
- Amitriptyline (increased amitriptyline levels)
- Nortriptyline (increased nortriptyline levels)
- Celecoxib (increased celecoxib levels)
- Losartan (decreased losartan active metabolite)
- Methadone (increased methadone levels)
- NSAIDs (e.g., ibuprofen, naproxen - increased NSAID levels)
- Oral Contraceptives (variable effect, potential for decreased efficacy)
- Vincristine (increased vincristine levels)
- Zidovudine (increased zidovudine levels)
Minor Interactions
- Cimetidine (minor decrease in fluconazole absorption)
Monitoring
Baseline Monitoring
Liver Function Tests (ALT, AST, ALP, Bilirubin)
Rationale: To establish baseline and identify pre-existing hepatic impairment, as fluconazole can cause hepatotoxicity.
Timing: Prior to initiation of therapy, especially for prolonged courses.
Renal Function (CrCl, SCr, BUN)
Rationale: Fluconazole is primarily renally eliminated; baseline assessment is crucial for dose adjustment.
Timing: Prior to initiation of therapy.
Electrolytes (Potassium, Magnesium)
Rationale: To assess baseline and identify risk factors for QT prolongation, especially in patients with cardiac conditions or on other QT-prolonging drugs.
Timing: Prior to initiation of therapy, if clinically indicated.
Routine Monitoring
Liver Function Tests (ALT, AST, ALP, Bilirubin)
Frequency: Periodically (e.g., weekly to monthly) for patients on prolonged therapy (e.g., >2 weeks) or those with underlying liver disease.
Target: Within normal limits or stable from baseline.
Action Threshold: Discontinue fluconazole if clinical signs/symptoms of liver disease develop or if LFTs significantly elevate (e.g., >3-5x ULN).
Renal Function (CrCl, SCr)
Frequency: Periodically for patients on prolonged therapy or those with changing renal status.
Target: Stable or within acceptable limits.
Action Threshold: Adjust dose if CrCl declines.
INR (for patients on warfarin)
Frequency: Frequently (e.g., daily to every few days) upon initiation and dose changes of fluconazole, then as clinically indicated.
Target: Therapeutic range for indication.
Action Threshold: Adjust warfarin dose to maintain target INR.
Blood Glucose (for patients on sulfonylureas)
Frequency: Monitor closely upon initiation and dose changes of fluconazole.
Target: Target glycemic control.
Action Threshold: Adjust sulfonylurea dose to prevent hypoglycemia.
Symptom Monitoring
- Signs of hepatotoxicity (e.g., unusual fatigue, anorexia, nausea, vomiting, jaundice, dark urine, pale stools)
- Skin rash or severe cutaneous reactions (e.g., Stevens-Johnson syndrome, toxic epidermal necrolysis)
- Signs of adrenal insufficiency (e.g., fatigue, weakness, dizziness, nausea, vomiting, hypotension)
- Signs of cardiac arrhythmias (e.g., palpitations, dizziness, syncope)
- Signs of allergic reaction (e.g., swelling of face/lips/tongue, difficulty breathing, hives)
Special Patient Groups
Pregnancy
Single oral dose (150 mg) for vaginal candidiasis is generally considered Category C, with limited data suggesting no increased risk of birth defects. However, chronic or high-dose fluconazole (e.g., 400-800 mg/day for prolonged periods) is Category D due to reports of a distinct pattern of birth defects (e.g., craniofacial, skeletal, cardiac abnormalities) in infants exposed during the first trimester. Use during pregnancy should be avoided unless the potential benefit justifies the potential risk to the fetus.
Trimester-Specific Risks:
First Trimester:
Increased risk of birth defects (craniofacial, skeletal, cardiac) with chronic/high-dose exposure. Single dose appears to have lower risk but still Category C.
Second Trimester:
Less data on specific risks, but generally avoided unless essential.
Third Trimester:
Less data on specific risks, but generally avoided unless essential.
Lactation
Fluconazole is excreted into breast milk. The amount transferred to the infant is small, and adverse effects in breastfed infants are generally not expected, especially with single doses. For prolonged or high-dose therapy, caution is advised, and the infant should be monitored for potential adverse effects (e.g., gastrointestinal upset, rash). Considered L2 (Safer).
Infant Risk:
Low risk for single dose; potential for mild GI upset or rash with prolonged exposure. Monitor infant.
Pediatric Use
Dosing is weight-based. Safety and efficacy have been established for children 6 months and older for certain indications. Neonatal use is off-label but common for serious infections, with adjusted dosing intervals due to immature renal function. Close monitoring for adverse effects is crucial.
Geriatric Use
No specific dose adjustment is needed based on age alone, but dose adjustments are required for age-related decline in renal function. Elderly patients may be more susceptible to QT prolongation and drug interactions due to polypharmacy and comorbidities. Monitor renal function and potential drug interactions closely.
Clinical Information
Clinical Pearls
- Fluconazole is highly effective for mucosal candidiasis and cryptococcal meningitis due to its excellent penetration into CSF and other body fluids.
- The long half-life allows for once-daily dosing, improving patient adherence.
- Be vigilant for drug interactions, especially with narrow therapeutic index drugs metabolized by CYP2C9, CYP2C19, or CYP3A4.
- Monitor liver function tests, especially during prolonged therapy, and discontinue if signs of hepatotoxicity occur.
- Counsel patients on the importance of completing the full course of therapy to prevent resistance and recurrence.
- For vaginal candidiasis, a single 150 mg dose is highly effective and convenient.
Alternative Therapies
- Other azole antifungals (e.g., Itraconazole, Voriconazole, Posaconazole)
- Echinocandins (e.g., Caspofungin, Micafungin, Anidulafungin) for invasive candidiasis
- Polyenes (e.g., Amphotericin B) for severe or resistant fungal infections
- Nystatin (topical/oral suspension for mucosal candidiasis)
- Clotrimazole (topical/troches for mucosal candidiasis)
Cost & Coverage
Average Cost:
Varies widely, typically $10-$50 per 30 tablets (50mg)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or 2 (most insurance plans cover generic fluconazole well)
General Drug Facts
If your symptoms or health issues persist or worsen, it is essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so it's a good idea to check with your pharmacist for more information. If you have any questions or concerns about this medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it happened.