ketoconazole vs posaconazole
Side-by-side comparison of ketoconazole and posaconazole Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
Nizoral
Noxafil
Ketoconazole shampoo is an antifungal medicine. It treats a fungal infection on your skin.
Posaconazole is an antifungal medicine. It helps prevent certain fungal infections in people with weakened immune systems.
This shampoo treats tinea versicolor, a fungal infection. This infection can cause patches on your skin that are lighter or darker than the surrounding skin. These patches may appear on your trunk, neck, arms, and upper thighs.
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.
Ketoconazole is an antifungal medicine. It works by stopping the growth of the fungus. 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.
No common side effects listed.
- • Diarrhea
- • Nausea
- • Fever
- • Vomiting
- • Headache
- The medicine did not work 1,582
- Using the medicine for something it's not approved for 1,174
- Feeling tired 929
- Itching 902
- Feeling sick to your stomach 834
- 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
You should not use this shampoo if you are allergic to ketoconazole or any of the other ingredients.
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.
It is not known if ketoconazole shampoo can harm an unborn baby. Talk to your doctor if you are pregnant or breastfeeding before using this medicine.
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 ketoconazole vs posaconazole Comparison
ketoconazole 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 split between OTC and prescription status, which affects access and supervision.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, ketoconazole has 5,421 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 ketoconazole 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.