Fluconazole: Side effects, dosage, uses, and more

Fluconazole oral tablet is available as both a generic and a brand-name drug. Brand name: Diflucan.
Fluconazole comes as a tablet or suspension you take by mouth. It also comes in an injectable form that can only be given to you by a healthcare professional.
Fluconazole oral tablet is used to prevent and treat candidiasis, a fungal infection. It's also used to treat meningitis (infection of the brain or spinal cord, or both).

Liver failure warning. This drug may cause you to develop liver failure. Your doctor may check your liver function with blood tests while you take this drug. If you develop liver failure from taking this drug, it's usually reversible once you stop taking it.
Skin rashes warning. This drug can cause a severe rash that can cause death. You should stop taking the drug if you develop any rashes.
Irregular heart rhythm warning. This drug can change how your heart beats. This change puts you at risk for a life-threatening heart rhythm condition called torsades de pointes. Your risk of heart rhythm problems is higher if you were born with a certain heart rhythm condition, you have a low potassium level, or you take antipsychotic drugs or certain antidepressants.
Adrenal gland problems. This drug can cause you to develop adrenal gland problems. Your adrenal gland produces hormones that affect many normal bodily functions. This problem may be reversible after stopping the drug.
Fetal harm warning. This drug may cause harm to the fetus if taken during pregnancy. Talk with your doctor if you can get pregnant. You may need to use birth control to prevent pregnancy while taking this drug.

Fluconazole is a prescription drug. It comes as a tablet or suspension you take by mouth.

Fluconazole oral tablet is available as both a generic drug and as the brand-name drug Diflucan.

Generic drugs usually cost less than the brand-name version. In some cases, they may not be available in all strengths or forms as the brand-name drug.

Why it's used

Fluconazole is used to prevent and treat candidiasis. This condition is caused by infection with one of the many types of the fungus Candida. Examples of candidiasis include vaginal yeast infection, as well as oral yeast infection (thrush).

Candidiasis can also cause infections on other parts of your body, including your throat, esophagus, lungs, and blood. People who have had bone marrow transplants may be treated with fluconazole to prevent candidiasis. This is because their immune systems are weakened, which makes them more likely to become infected with a severe form of candidiasis.

Fluconazole is also used to treat meningitis (infection of the brain and spinal cord) that's caused by the fungus Cryptococcus.

How it works

Fluconazole belongs to a class of drugs called triazole antifungals. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.

Fluconazole works by blocking the ability of the fungi Candida and Cryptococcus to reproduce. For people with infections from these fungi, this drug helps to get rid of the infection. For people at higher risk of candidiasis, it helps to prevent infection.

Fluconazole isn't known to cause drowsiness, but it can cause other side effects.

More common side effects

The more common side effects of fluconazole oral tablet depend on how much of the drug you need to take. These side effects can include:

If these effects are mild, they may go away within a few days or a couple of weeks. If they're more severe or don't go away, talk with your doctor or pharmacist.

Serious side effects

Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life threatening or if you think you're having a medical emergency. Serious side effects and their symptoms can include the following:

Liver damage. Symptoms can include:
- yellowing of your skin or the whites of your eyes
- dark urine
- light-colored stools
- severe skin itching
- vomiting or nausea
Severe rash in people with acquired immunodeficiency syndrome (AIDS) or cancer. Symptoms can include:
- skin peeling
- severe rash
Torsades de pointes (a life-threatening heart rhythm condition). Symptoms can include:
- feeling like your heart is skipping a beat (palpitations)
- fast, irregular heart rate
- dizziness
- fainting
- seizures
Adrenal gland problems. Symptoms can include:
- muscle weakness
- belly pain
- fatigue
- loss of appetite

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always speak with your doctor or pharmacist about dosages that are right for you.

Fluconazole oral tablet can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well.

To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you're taking. To find out how this drug might interact with something else you're taking, talk with your doctor or pharmacist.

Examples of drugs that can cause interactions with fluconazole are listed below.

Drugs that should not be used with fluconazole

There are certain drugs that you should not use with fluconazole. When used with fluconazole, these drugs can cause dangerous effects in your body. Examples of these drugs include:

Terfenadine. When used with fluconazole at doses of 400 mg or higher, this drug can cause a life-threatening heart rhythm condition called torsades de pointes.
Pimozide, clarithromycin, erythromycin, ranolazine, lomitapide, donepezil, voriconazole, and quinidine. When used with fluconazole, these drugs can cause a life-threatening heart rhythm condition called torsades de pointes.

Drugs that increase the risk of side effects

Taking fluconazole with certain drugs raises your risk of side effects from those drugs. Examples of these drugs include:

Diabetes drugs such as glyburide and glipizide. Increased side effects can include low blood sugar. This causes symptoms such as sweating and chills, shakiness, fast pulse, weakness, hunger, and dizziness.
Warfarin. Increased side effects can include bruising, nosebleeds, and blood in your urine or stools.
Phenytoin. Taking this drug with fluconazole can cause trouble with coordination, slurred speech, and confusion. Your doctor will measure blood levels of phenytoin while you're taking fluconazole. It's possible that your doctor will decrease your dose of phenytoin while you're taking fluconazole.
Cyclosporine, tacrolimus, and sirolimus. Increased side effects can include kidney damage. Your doctor will check your blood for signs of kidney damage while you're taking fluconazole. If you show signs of kidney damage, your doctor may lower your doses of these drugs or stop them completely until your treatment with fluconazole is done.
Theophylline. Taking this drug with fluconazole can cause muscle cramps, headache, low blood pressure, and seizures. Your doctor will measure blood levels of phenytoin while you're taking fluconazole.
Zidovudine. Increased side effects can include headache, tiredness, loss of appetite, nausea, and vomiting.
Pain drugs, such as methadone and fentanyl. The levels of these drugs may be increased in your body when taken with fluconazole. Increased side effects include slower breathing, confusion, and drowsiness.
Carbamazepine. Increased side effects include nausea, vomiting, unsteadiness, low blood cell counts, severe rash, heart failure, and liver failure.
Certain calcium channel blockers, such as nifedipine, amlodipine, verapamil, and felodipine. Increased side effects include low blood pressure, dizziness, confusion, and headache.
Certain statins, such as atorvastatin and simvastatin. Increased side effects include muscle pain and weakness and raised levels of creatinine in your blood.
Antipsychotic drugs, such as chlorpromazine, haloperidol, and ziprasidone. Taking fluconazole with these medications raises your risk of a life-threatening irregular heart rhythm condition called torsades de pointes.
Antidepressants, such as citalopram, escitalopram, and paroxetine. Taking fluconazole with these medications raises your risk of a life-threatening irregular heart rhythm condition called torsades de pointes.
Heart rhythm drugs, such as amiodarone and dofetilide. Taking fluconazole with these medications raises your risk of a life-threatening irregular heart rhythm condition called torsades de pointes.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare professional about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.

Fluconazole oral tablet comes with several warnings

Allergy warning

This drug can cause a severe allergic reaction. Symptoms can include:

shortness of breath
coughing
wheezing
fever
chills
throbbing of your heart or ears
swelling of your eyelids, face, mouth, neck, or any other part of your body
skin rash, hives, blisters or skin peeling

If you have an allergic reaction, call your doctor or local poison control center right away. If your symptoms are severe, call 911 or go to the nearest emergency room.

Don't take this drug again if you've ever had an allergic reaction to it. Taking it again could be fatal (cause death).

Warnings for people with certain health conditions

For people with kidney disease: If you have kidney disease or a history of kidney disease, your kidneys may not be able to remove this drug from your body like they should. This may increase the levels of fluconazole in your body and cause more side effects. This drug may also make existing kidney disease worse.

People with liver problems: Fluconazole can cause liver problems. If you already have liver problems, talk with your healthcare professional before taking this drug.

People with high blood sugar levels: The oral suspension form of this drug contains sucrose, a kind of sugar. You shouldn't use this form of the drug if you have a condition that increases your blood sugar level. Talk with your doctor before using this drug if you have high blood sugar levels or a condition, such as diabetes, which can cause high blood sugar levels.

People with abnormal heart rhythms: Using fluconazole can affect your heart rhythm. If you already have an abnormal heart rhythm, taking fluconazole may lead to dangerous heart rhythm problems.

People with certain conditions that lower immunity: If you have certain conditions that lower your immunity, such as cancer, human immunodeficiency virus infection (HIV), or acquired immunodeficiency syndrome (AIDS) you're more likely to get a rash from fluconazole. Your doctor will monitor you for a rash and peeling skin.

Warnings for other groups

Pregnant women: Research in humans has shown adverse effects to the fetus when the mother takes this drug in doses of 150 mg or higher. In lower doses, research in animals has shown adverse effects. There haven't been enough studies done to be certain how lower doses of the drug might affect the human fetus.

This drug should only be used during pregnancy in serious cases where it's needed to treat a dangerous infection in the mother. And it should only be used if the potential risk to the fetus is acceptable given the drug's potential benefit.

Talk with your doctor if you're pregnant or planning to become pregnant. Ask your doctor to tell you about the specific harm that may be done to the fetus.

If you become pregnant while taking this drug, call your doctor right away.

Women who are breastfeeding: Fluconazole passes into breast milk and may cause side effects in a child who is breastfed. Talk with your doctor if you breastfeed your child. You may need to decide whether to stop breastfeeding or stop taking this drug.

For seniors: The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This raises your risk of side effects.

For children: This medication shouldn't be used in people younger than 6 months.

This dosage information is for fluconazole oral tablet. All possible dosages and drug forms may not be included here. Your dosage, drug form, and how often you take the drug will depend on:

your age
the condition being treated
how severe your condition is
other medical conditions you have
how you react to the first dose

Forms and strengths

Generic: Fluconazole

Form: Oral tablet
Strengths: 50 mg, 100 mg, 150 mg, 200 mg

Brand: Diflucan

Form: Oral tablet
Strengths: 50 mg, 100 mg, 150 mg, 200 mg

Dosage for vaginal candidiasis

Adult dosage (ages 18–64 years)

Typical dosage: One 150-mg dose.

Child dosage (ages 0–17 years)

Use of this drug hasn't been approved in children younger than 18 years.

Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This raises your risk of side effects. Your doctor may start you on a lowered dose or a different dosing schedule. This can help keep levels of this drug from building up too much in your body.

Dosage for nonvaginal candidiasis

Adult dosage (ages 18–64 years)

Typical dosage: Depending on the type of infection you have, your daily dose could be between 50 mg and 400 mg.
Treatment length: Treatment can last up to several weeks.

Child dosage (ages 6 months through 17 years)

Typical dosage: Dosage depends on the weight of the child taking the drug, and the type of infection being treated.
Treatment length: The length of treatment depends on the infection being treated.

Child dosage (ages 0–5 months)

Use of this drug isn't recommended in infants younger than 6 months.

Senior dosage (ages 65 years and older)

Dosage for candidiasis prevention

Adult dosage (ages 18–64 years)

Typical dosage: 400 mg, taken once per day.
Treatment length: Treatment can last several weeks.

Child dosage (ages 0–17 years)

Use of this drug for the prevention of candidiasis in people younger than 18 years hasn't been approved.

Senior dosage (ages 65 years and older)

Dosage for cryptococcal meningitis

Adult dosage (ages 18–64 years)

Typical dosage: 400 mg on the first day. The dose from day 2 on is usually 200–400 mg, taken once per day.
Treatment length: Treatment typically lasts 10–12 weeks after a test called a cerebrospinal fluid culture no longer detects fungi.

Child dosage (ages 6 months through 17 years)

Dosage for children is based on weight.

Typical dosage: On the first day, your child will take 12 mg per kilogram of body weight. The dose from day 2 on is usually 6–12 mg per kilogram, taken once per day.
Treatment length: Treatment typically lasts 10–12 weeks after a test called a cerebrospinal fluid culture no longer detects fungi.

Child dosage (ages 0–5 months)

Use of this drug isn't recommended in infants younger than 6 months.

Senior dosage (ages 65 years and older)

Special dosage considerations

For people with kidney disease: If you have kidney disease and are supposed to take more than a single dose of fluconazole, your dose may be lowered. Your doctor may give you a first dose of 50–400 mg, with additional doses that range between that amount and half of that amount, based on your kidney function.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always to speak with your doctor or pharmacist about dosages that are right for you.

Fluconazole oral tablet is used for both short-term and long-term treatment. It comes with risks if you don't take it as prescribed.

If you stop taking the drug suddenly or don't take it at all: Your infection may not get better or may get worse.

If you miss doses or don't take the drug on schedule: Your medication may not work as well or may stop working completely. For this drug to work well, a certain amount needs to be in your body at all times.

If you take too much: You could have dangerous levels of the drug in your body. Symptoms of an overdose of this drug can include:

hallucinations
paranoia
abnormal heart rhythm
blue tint to your skin
decreased breathing

If you think you've taken too much of this drug, call your doctor or local poison control center. If your symptoms are severe, call 911 or go to the nearest emergency room right away.

What to do if you miss a dose: Take your dose as soon as you remember. But if you remember just a few hours before your next scheduled dose, take only one dose. Never try to catch up by taking two doses at once. This could result in dangerous side effects.

How to tell if the drug is working: You should have decreased symptoms of infection.

Keep these considerations in mind if your doctor prescribes fluconazole oral tablet for you.

General

You can take fluconazole with or without food.
You can cut or crush the tablet.

Storage

Store fluconazole tablets below 86°F (30°C).
Don't store this medication in moist or damp areas, such as bathrooms.

Refills

A prescription for this medication is refillable. You should not need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.

Travel

When traveling with your medication:

Always carry your medication with you. When flying, never put it into a checked bag. Keep it in your carry-on bag.
Don't worry about airport X-ray machines. They can't hurt your medication.
You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled box with you.
Don't put this medication in your car's glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.

Clinical monitoring

Your doctor should monitor your kidney and liver function while you take this drug. Your doctor should have blood tests done to check how well your liver and kidneys are working. If these organs aren't working well, your doctor may decide to lower your dosage or have you stop taking this drug.

There are other drugs available to treat your condition. Some may be better suited for you than others. Talk with your doctor about other drug options that may work for you.

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.

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