fluconazole vs posaconazole
Side-by-side comparison of fluconazole and posaconazole Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
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Fluconazole is an antifungal medicine. It is used to treat infections caused by fungus.
Posaconazole is an antifungal medicine. It helps prevent certain fungal infections in people with weakened immune systems.
Fluconazole treats vaginal yeast infections. It also treats yeast infections in the mouth and esophagus. Fluconazole can also treat urinary tract infections, peritonitis, systemic Candida infections, and pneumonia. It can also treat cryptococcal meningitis. Fluconazole can also prevent candidiasis in patients undergoing bone marrow transplantation.
Posaconazole prevents Aspergillus and Candida infections. You may need this medicine if you have a high risk of getting these infections. This often includes people who had a stem cell transplant or have certain blood cancers and are on chemotherapy.
Fluconazole works by stopping the growth of fungi. It blocks the fungus from producing a substance it needs to grow. This helps to clear up the infection.
Posaconazole belongs to a class of drugs called azole antifungals. It works by stopping the growth of fungi. This helps your body fight off the infection.
- • Headache
- • Nausea
- • Abdominal pain
- • Diarrhea
- • Nausea
- • Fever
- • Vomiting
- • Headache
- Medicine not working 4,932
- Using medicine for unapproved purpose 4,329
- Fever 4,121
- Feeling sick to your stomach 3,695
- Loose stools 3,536
- Using the medicine for a condition it is not approved for 1,542
- The medicine is not working 1,434
- Fever with low white blood cell count 1,018
- The medicine is interacting with another medicine 930
- Death 928
Coadministration of other drugs known to prolong the QT interval and which are metabolized via the enzyme CYP3A4 such as erythromycin, pimozide, and quinidine are contraindicated in patients receiving fluconazole.
Posaconazole can interact with many other medicines. It can cause heart rhythm problems (QT prolongation). It can also cause liver problems. Tell your doctor about all the medicines you take.
Tell your doctor if you are pregnant or plan to become pregnant. Fluconazole may not be safe for your baby. Talk to your doctor about breastfeeding while taking fluconazole.
Posaconazole may harm an unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. It is not known if posaconazole passes into breast milk, so talk to your doctor if you are breastfeeding.
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How to Read This fluconazole vs posaconazole Comparison
fluconazole is classified in the Azole Antifungal drug class, while posaconazole sits within the Azole Antifungal class. Because both drugs share the same classification, they are often considered interchangeable in theory — but clinical outcomes rarely track that cleanly. Both drugs are prescription-only, so a licensed provider must authorize use.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, fluconazole has 20,613 submissions while posaconazole has 5,852. Those figures reflect cumulative reporting volume — not per-patient risk — so older, widely dispensed drugs typically look worse on count alone. No direct interaction between these two drugs is listed in our FDA-derived dataset, though co-prescription still warrants pharmacist review. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.
A table cannot substitute for clinical judgment. Effectiveness, tolerability, drug-drug interactions with your other medications, kidney and liver function, pregnancy status, insurance formulary, and price all feed into a decision that only a licensed prescriber can make responsibly. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This page is for educational purposes only, is not medical advice, and should not be used to self-switch between fluconazole and posaconazole — always consult your physician or pharmacist first.
Important: This comparison is for informational purposes only. Drug effects vary between individuals. Always consult your doctor or pharmacist for personalized medical advice.