Ketoconazole | Side Effects, Dosage, Uses & More
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Generic Name:

ketoconazole, Oral tablet

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  • Nizoral (Discontinued)
A discontinued drug is a drug that has been taken off the market due to safety issues, shortage of raw materials, or low market demand.
SECTION 1 of 5

Highlights for ketoconazole

Oral tablet
1

Ketoconazole is used to treat fungal and yeast infections on your skin, hair, nails, and in your blood.

2

This drug is available as an oral tablet, topical cream, topical foam, shampoo, and topical gel.

3

Ketoconazole oral tablet is only available as a generic drug.

4

The more common side effects of this drug include nausea, headache, diarrhea, stomach pain, and abnormal liver function test results.

5

In some cases, ketoconazole can cause serious side effects. These can include liver problems.

IMPORTANT INFORMATION

FDA warning

This drug has a black box warning. This is the most serious warning from the Food and Drug Administration (FDA). A black box warning alerts doctors and patients about drug effects that may be dangerous.

Liver failure warning. This drug can cause liver failure. Your doctor will monitor your liver function while you’re on this medication.

Not for use as a first treatment. This drug should only be used when other treatments aren’t an option or when the possible benefits of this drug outweigh the risks. These serious risks include liver failure and heart rhythm problems.

Hormone problems

High doses of this drug can affect your body’s ability to secrete hormones in response to stress. Symptoms can include extreme thirst, weight loss, darkening of your skin, unusual tiredness, joint aches and pains, and loss of appetite. If you have these symptoms, call your doctor.

What is ketoconazole?

Ketoconazole is a prescription drug. It’s available as an oral tablet, topical cream, topical foam, shampoo, and topical gel.

The oral tablet is only available as a generic drug.

Why it's used

Ketoconazole is used to treat fungal and yeast infections on your skin, hair, nails, and in your blood.

This drug is only given when other treatments haven’t worked or caused too many side effects.

How it works

Ketoconazole belongs to a class of drugs called 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. 

Ketoconazole works to stop fungi and yeasts from causing an infection.

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ketoconazole Side Effects

Oral tablet

More Common Side Effects

Some of the more common side effects of ketoconazole include:

  • nausea

  • headache

  • diarrhea

  • stomach pain

  • abnormal liver function test results

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 to your doctor or pharmacist.

Serious Side Effects

Call your doctor right away if you have serious side effects. Call 9-1-1 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 problems (hepatotoxicity). Symptoms can include:

    • loss of appetite or weight loss (anorexia)
    • nausea or vomiting
    • tiredness
    • stomach pain or tenderness
    • dark-colored urine or light-colored stools
    • yellowing of your skin or the whites of your eyes
    • fever
    • rash
Pharmacist's Advice
Clinical Associate Professor, University of Illinois at Chicago College of Pharmacy

Ketoconazole doesn’t cause drowsiness.

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 information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.
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ketoconazole May Interact with Other Medications

Oral tablet

Ketoconazole 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 to your doctor or pharmacist.

Alcohol interaction

You shouldn’t drink alcohol while taking ketoconazole. Drinking alcohol can increase your risk of liver damage while taking this drug. If you drink alcohol, talk to your doctor.

Medications that might interact with this drug

Drugs you should not use with ketoconazole

Do not take these drugs with ketoconazole. Doing so can cause dangerous effects in the body. Examples of these drugs include:

  • Antiarrhythmic drugs, such as dofetilide, quinidine, and dronedarone. Taking these drugs with ketoconazole may cause a heart problem called QT prolongation. This is a change in the electrical activity in the heart. It can cause irregular heartbeats and be life-threatening.
  • Methadone. Taking these drugs together may cause a heart problem called QT prolongation. This is a change in the electrical activity in the heart. It can cause irregular heartbeats and be life-threatening.
  • Ranolazine. Taking these drugs together may cause a heart problem called QT prolongation. This is a change in the electrical activity in the heart. It can cause irregular heartbeats and be life-threatening.  
  • Simvastatin or lovastatin. Taking ketoconazole with these drugs may cause muscle problems.
  • Triazolam, midazolam, or alprazolam. Taking these drugs together may make you feel very drowsy for a long period of time.
  • Eplerenone. Taking these drugs together may cause low blood pressure and low potassium levels.

Interactions that increase your risk of side effects
  • Side effects from ketoconazole: Taking ketoconazole with certain medications raises your risk of side effects from ketoconazole. This is because the amount of ketoconazole in your body is increased. Examples of these drugs include:
    • ritonavir
    • atorvastatin
  • Side effects from other drugs: Taking ketoconazole with certain medications raises your risk of side effects from these drugs. Examples of these drugs include:
    • Pain drugs, such as buprenorphine, fentanyl, and oxycodone. Taking these drugs with ketoconazole may cause slowed breathing.
    • Anticoagulants, such as rivaroxaban, dabigatran, and warfarin. Taking these drugs with ketoconazole may increase your risk of bleeding.
    • Heart drugs, such as felodipine and nisoldipine. Taking these drugs with ketoconazole may cause swelling of your legs or arms and heart failure.
    • Tamsulosin. Taking these drugs together may cause headache, dizziness, and orthostatic hypotension (low blood pressure when you stand up from a sitting or lying position).
    • Digoxin. Taking these drugs together may cause dizziness, headache, and stomach pain. Your doctor may monitor your digoxin blood levels.
    • Eletriptan. Taking these drugs together may cause weakness, nausea, dizziness, and drowsiness.
    • Antipsychotic drugs, such as aripiprazole, buspirone, haloperidol, quetiapine, and risperidone. Taking these drugs with ketoconazole may cause dizziness, drowsiness, and headaches.
    • Ramelteon. Taking these drugs together may cause dizziness, drowsiness, and fatigue.
    • Antivirals such as indinavir, maraviroc, and saquinavir. Taking these drugs with ketoconazole may cause stomach pain, nausea, and headaches.
    • Blood pressure drugs, such as verapamil and aliskiren. Taking these drugs with ketoconazole may cause low blood pressure, low heart rate, and dizziness.
    • Drugs for erectile dysfunction, such as sildenafil, tadalafil, and vardenafil. Taking these drugs with ketoconazole may cause headaches, upset stomach, and muscle pain.
    • Drugs for urine problems, such as solifenacin and tolterodine. Taking these drugs with ketoconazole may cause dry mouth, headaches, and dizziness.

Interactions that can make your drugs less effective
  • When ketoconazole is less effective: When ketoconazole is used with certain drugs, it may not work as well to treat your condition. This is because the amount of ketoconazole in your body may be decreased. Examples of these drugs include:

    • Ranitidine, famotidine, cimetidine, pantoprazole, omeprazole, and rabeprazole. You should take ketoconazole with an acidic beverage, such as a non-diet soda, if you take these drugs together.
    • Aluminum hydroxide. You should take this drug 1 hour before or 2 hours after taking ketoconazole.
    • Antibiotics, such as isoniazid and rifabutin
    • Anticonvulsants, such as carbamazepine and phenytoin
    • Antivirals, such as efavirenz and nevirapine
    • Carbamazepine. Your doctor may monitor your carbamazepine levels.

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 provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.
Drug warnings
Pregnant women
Pregnant women

Ketoconazole is a category C pregnancy drug. That means two things:

  1. Research in animals has shown adverse effects to the fetus when the mother takes the drug.
  2. There haven’t been enough studies done in humans to be certain how the drug might affect the fetus.

Talk to your doctor if you’re pregnant or planning to become pregnant. This drug should be used only if the potential benefit justifies the potential risk to the fetus.

breastfeeding
Women who are breast-feeding

Ketoconazole passes into breast milk and may cause side effects in a child who is breast-fed.

Talk to your doctor if you breast-feed your child. You may need to decide whether to stop breast-feeding or stop taking this medication.

for children
For children

It hasn’t been confirmed that ketoconazole is safe and effective for use in people younger than 2 years. In general, ketoconazole tablets shouldn’t be used in children.

call doctor
When to call the doctor

Your symptoms may start to get better after 24 hours of starting this drug. If your symptoms don’t start to go away after using this drug for a few days, call your doctor.

allergies
Allergies

Ketoconazole tablets 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, peeling of your skin  

If you have an allergic reaction, call your doctor or local poison control center right away. If your symptoms are severe, call 9-1-1 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).

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How to Take ketoconazole (Dosage)

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

What are you taking this medication for?

Fungal infections from various types of fungi

Generic: ketoconazole

Form: Oral tablet
Strengths: 200 mg
Adult dosage (ages 18 years and older)

200 mg taken once per day for up to 6 months. Your doctor may increase your dose to 400 mg taken once per day if needed.

Child dosage (ages 2–17 years)

Your doctor will decide a dose based on your child’s weight. The dose will range from 3.3–6.6 mg/kg of body weight taken once per day.

Child dosage (ages 0–1 years)

It hasn’t been confirmed that ketoconazole is safe and effective for use in people younger than 2 years. In general, ketoconazole tablets shouldn’t be used in children.

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.
Pharmacist's Advice
Clinical Associate Professor, University of Illinois at Chicago College of Pharmacy

Ketoconazole comes with risks if you don’t take it as prescribed.

If you stop taking the drug or don’t take it at all

Your infection or skin condition won’t get better.  

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:

  • nausea
  • vomiting
  • diarrhea

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 9-1-1 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

Your skin condition or infection should improve.

Ketoconazole is used for short-term treatment.

However, sometimes it needs to be taken for several months.

Store this drug carefully

  • Store it between 68°F and 77°F (20°C and 25°C).
  • Protect it from moisture and light.
  • Keep it out of the reach of children.

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

You may need to have your liver function monitored while you take ketoconazole tablets. This will help make sure that your liver is working well while you take this drug.

This monitoring may be done using:

  • Liver function tests. Your doctor may do blood tests to check how well your liver is working. If your liver isn’t working well, your doctor may have you stop taking this drug.

You may need to have your heart rhythm monitored while you take this drug.

This monitoring may be done using:

  • Heart rhythm tracing (ECG). Your doctor may do this test to check if your heart rhythm is normal. If it isn’t, your doctor may have you stop taking this drug.

Sun sensitivity

Ketoconazole can make your skin more sensitive to the sun. This increases your risk of sunburn. Stay out of the sun if you can. If you need to be outside, be sure to wear protective clothing and sunscreen.

Are there any alternatives?

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

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How Much Does ketoconazole Cost?

Oral tablet

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Lowest price for ketoconazole

Sams Club $10.00
Walmart $33.55
CVS Pharmacy $46.27
These prices represent the lowest priced national pharmacies for ketoconazole on GoodRx. They may be lower than your insurance.

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These prices represent the lowest priced national pharmacies for ketoconazole on GoodRx. They may be lower than your insurance.

Show Sources

Content developed in collaboration with University of Illinois-Chicago, Drug Information Group

Medically reviewed by Creighton University, Center for Drug Information and Evidence-Based Practice on December 8, 2015

Disclaimer: Healthline 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 other 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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