7 Fluconazole (Diflucan) Side Effects and How to Manage Them

Fluconazole side effects at a glance

Here’s an overview of side effects reported by people taking fluconazole during clinical trials. The likelihood of experiencing these side effects can depend on your dose and length of treatment.

Common or mild fluconazole side effects include:

• Headache

• Nausea

• Vomiting

• Abdominal pain

• Diarrhea

• Upset stomach

• Dizziness

• Taste changes

• Skin rash

Rare but potentially serious fluconazole risks include:

• Liver damage

• Severe skin problems

• Severe allergic reactions (including anaphylaxis and angioedema)

• QT prolongation

Below, we take a closer look at seven fluconazole side effects and tips for managing them.

1. Nausea

Nausea is one of the most common side effects of fluconazole. Usually, nausea from fluconazole is mild and resolves after finishing a treatment course. But here are a few tips to help in the meantime:

• Take it with food. Fluconazole can be taken with or without food. But taking it with a meal or a snack may help reduce stomach upset.

• Eat smaller, more frequent meals. It also helps to avoid heavy, greasy, or spicy foods, which may make nausea worse.

• Try bland foods. Foods such as bananas, rice, and toast can be more gentle on your stomach.

If you have nausea that is persistent or severe or comes with other symptoms (such as yellowing of the skin or dark urine), tell your prescriber right away.

2. Headache

Headache is another common fluconazole side effect, especially when it’s taken as a single dose. Similar to nausea, the headaches tend to be mild and should resolve on their own. To help prevent or manage headaches while taking fluconazole:

• Stay hydrated. Dehydration can make headaches worse, so drink plenty of water throughout the day.

• Get adequate rest. Do your best to get enough sleep and rest in a quiet, dark room if you feel a headache coming on.

• Try over-the-counter pain relievers. If your healthcare team says it’s safe, medications such as acetaminophen (Tylenol) can help ease headache pain.

Tell your prescriber if your headaches become severe or won’t go away. There may be other reasons you’re experiencing headaches. They can help determine the likely causes and recommend the best way to relieve your symptoms.

3. Stomach pain

Taking fluconazole may also cause stomach pain. For most people, it’s mild and temporary, often resolving on its own after you finish taking the medication. But in some cases, the discomfort can linger or become bothersome.

To help prevent or manage stomach pain while taking fluconazole:

• Take it with a meal or a snack. Similar to nausea, taking fluconazole with food may help ease stomach pain or discomfort.

• Eat smaller, more frequent meals. Eating smaller portions more often instead of large meals may be easier on your stomach.

• Avoid foods that cause gas. Gas-producing foods, such as beans, can make stomach pain worse for some people.

If your stomach pain is severe, lasts longer than a few days, or is accompanied by nausea, vomiting, or bloating, contact your prescriber right away. They can determine whether fluconazole is the cause and how to manage it.

4. Diarrhea

Diarrhea can occur as a side effect of fluconazole, but it’s usually mild and temporary. It may happen because the medication slightly disrupts the natural balance of bacteria in your gut. Most cases resolve on their own within a few days.

To manage diarrhea at home:

• Drink enough fluids. Drink plenty of fluids, such as water or electrolyte drinks, to prevent dehydration.

• Eat a bland diet. Stick to foods such as bananas, rice, and toast while your symptoms persist.

• Avoid triggers. Steer clear of fatty, greasy, or spicy foods, as well as caffeine and alcohol.

If your diarrhea is severe, lasts more than a few days, or is accompanied by signs of dehydration, contact your prescriber. They may recommend an over-the-counter antidiarrheal medication or further evaluation.

5. Skin rashes

Skin rashes are possible with fluconazole. This side effect wasn’t reported in trials of people taking a single dose of fluconazole. But some people with longer treatment courses reported skin rashes. And in rare cases, fluconazole has been linked to serious skin reactions that require medical care.

If you notice a new rash after starting fluconazole, contact your prescriber. This is good to do even if it feels mild. They may recommend monitoring the rash or switching medications. Seek emergency care right away if the rash:

• Comes with hives, blisters, or peeling skin

• Is spreading quickly

• Is accompanied by fever, swelling, difficulty breathing, or throat tightness

These could be signs of a rare but life-threatening reaction such as Stevens-Johnson syndrome or anaphylaxis, which require immediate treatment in a hospital.

6. Liver damage

Liver damage is a rare but serious fluconazole side effect. In many cases, it is mild and may not cause noticeable symptoms. But more severe liver damage has been reported, especially in people who already have liver disease or are taking other medications that affect the liver.

Most people who develop liver damage recover once they stop taking fluconazole. But early detection is key. Your healthcare team may want to monitor your liver function with lab tests more closely during treatment. Tell them right away if you notice any of the following symptoms:

• Dark-colored urine

• Yellowing of the eyes or skin (jaundice)

• Extreme fatigue

• Itching across your body

• Light-colored stool

7. Heart rhythm changes

Heart rhythm changes, such as QT prolongation, are rare. But they are a possible fluconazole side effect. QT prolongation is when the heart takes longer than normal to recharge between beats. In some cases, this can lead to serious heart rhythm problems.

Common symptoms of QT prolongation can include lightheadedness, blurry vision, and heart palpitations. Fainting is also common, especially while exercising. Get immediate medical attention if these symptoms develop while taking fluconazole.

The risk for QT prolongation increases if you take certain medications that interact with fluconazole. These include amiodarone, quinidine, and others. Make sure to give your prescriber and pharmacist a current list of your medications. This will help them screen for interactions.

You can also have a higher risk for QT prolongation if you have kidney damage. Tell your prescriber if you have kidney problems before starting fluconazole.

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Written by:

Austin Ulrich, PharmD, BCACP

​​Austin Ulrich, PharmD, BCACP, is a board-certified ambulatory care clinical pharmacist. Ulrich’s experience includes direct patient care in hospital and community pharmacies.

Edited by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

Reviewed by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

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