Fluconazole: what it treats, how to take it, side effects
Last updated September 3, 2026.
Fluconazole is an antifungal that treats infections caused by yeast and other fungi. You may know it as Diflucan. Its best-known job is clearing a vaginal yeast infection with a single pill, but it also treats more serious fungal infections elsewhere in the body.
What does it treat?
The label's headline use is vaginal candidiasis (a vaginal yeast infection due to Candida), treated with one 150 mg tablet. MedlinePlus adds that doctors also prescribe it for fungal infections of the mouth, throat, esophagus, lungs, and other organs, and sometimes to prevent fungal infections in people at high risk, such as those with HIV, cancer, or an organ transplant.
How do you take it?
As a tablet or liquid, usually once a day, with or without food. For some infections you take only one dose; for others, treatment runs several weeks or longer. Your doctor may have you take a double dose on the first day - the label explains this loading dose brings the drug up to working levels by day two. Shake the liquid well. You should feel better within the first few days, but keep taking it until your doctor says stop, because quitting early can let the infection come back. Missed dose: take it when you remember unless the next one is close; never double up.
Side effects to know
- Common: headache, dizziness, diarrhea, stomach pain, heartburn, and a change in how food tastes.
- Serious: liver problems - nausea, vomiting, extreme tiredness, loss of appetite, pain in the upper right stomach, yellowing skin or eyes, dark urine, pale stools, and flu-like symptoms. Also serious: unusual bruising or bleeding, seizures, and allergic or skin reactions including rash, blistering or peeling skin, hives, itching, facial or throat swelling, and difficulty breathing or swallowing.
Who should not take it?
Fluconazole has a long interaction list. MedlinePlus says some medications should not be taken with it at all (the label contraindicates combining it with quinidine because of heart rhythm risk) and flags even over-the-counter NSAIDs like ibuprofen and naproxen as worth a pharmacist conversation. It also increases the effect of warfarin, per the label. Tell your doctor about cancer, AIDS, an irregular heartbeat, low calcium, sodium, magnesium, or potassium, lactose or sucrose intolerance, and heart, kidney, or liver disease. Pregnancy needs a direct conversation: fluconazole may harm the fetus, MedlinePlus highlights the first 3 months especially, and your doctor may tell you to use birth control during treatment and for 1 week after your final dose. The drug can cause dizziness or seizures, so hold off on driving until you know how it affects you.
When is it an emergency?
Call 911 for trouble breathing or swallowing, facial or throat swelling, seizures, or fainting. Blistering or peeling skin, or yellowing skin or eyes with dark urine, means calling your doctor immediately. For an overdose, call Poison Control at 1-800-222-1222. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
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Common questions
Is one fluconazole pill really enough for a yeast infection?
For vaginal candidiasis, yes - the label's regimen is a single 150 mg oral dose, and its clinical studies found that single dose comparable to 7 days of vaginal antifungal products. Other fungal infections take longer courses, sometimes weeks. If symptoms are still there after you finish, call your doctor instead of self-repeating the dose.
Can I drink alcohol while taking fluconazole?
Neither the FDA label nor MedlinePlus lists a specific alcohol interaction for fluconazole. Since the drug can cause dizziness and, rarely, liver problems, many clinicians suggest going easy or skipping it during treatment - ask your doctor for advice on your situation.
Does fluconazole interact with other medications?
Yes, and this is the drug's biggest practical issue. MedlinePlus says some medications cannot be taken with fluconazole at all, others need dose changes or extra monitoring, and even over-the-counter NSAIDs like ibuprofen and naproxen should be discussed first. The label also shows it increases warfarin's blood-thinning effect. Bring your full medication list to the prescriber.
Can I take fluconazole while pregnant?
That is a doctor conversation, not a default. MedlinePlus says fluconazole may harm the fetus, highlights the first 3 months of pregnancy especially, and notes your doctor may tell you to use birth control during treatment and for 1 week after your final dose. If you become pregnant while taking it, call your doctor.
How fast does fluconazole work?
MedlinePlus says you should begin to feel better during the first few days of treatment. A loading dose, when prescribed, gets the drug to working levels faster. If symptoms do not improve or get worse, call your doctor.
Does fluconazole affect birth control pills?
Neither source flags a reduction in hormonal birth control effectiveness for fluconazole. MedlinePlus does say your doctor may ask you to use birth control during treatment to prevent pregnancy because of fetal risk - that is a different point, and worth clarifying with your prescriber if you are unsure which applies to you.