00:00 / 00:00




0 / 11 complete



of complete

External References

First Aid








Ketoconazole p. 195, 196, 682

cytochrome P p. -473, 253

gynecomastia from p. 673

PCOS p. 669

reproductive hormones and p. 679


The “azole” antifungals are a family of medications used to treat mycoses, or fungal infections.

Mycoses can be superficial, like on the skin or hair, or develop into systemic infections in immunodeficient people.

Antifungals work either through fungistatic action, meaning that they inhibit fungal growth, or through fungicidal action, meaning they kill the fungi.

Azoles are divided into two major families of antifungals: imidazoles and triazoles.

Most fungal cells have a tough outer cell wall and an inner cell membrane.

The cell membrane is mostly made of phospholipids with some sterol or modified steroid molecules mixed in.

Humans have cholesterol, while fungi have ergosterol.

Both sterol molecules help keep the cell membrane stable at a wide range of temperatures.

Now, the precursor to both molecules is lanosterol.

Fungi have a cytochrome p450 enzyme called fourteen-alpha-demethylase in their mitochondria and endoplasmic reticulums, which converts lanosterol to ergosterol.

Without ergosterol, the structure of the cell membrane will be disrupted.

This will cause membrane-bound proteins, like ion channels, to stop working properly.

The membrane also becomes fragile, which eventually leads to inhibition of fungal growth.

The azole antifungals include imidazoles, like clotrimazole, isoconazole, miconazole, butoconazole, fenticonazole, and ketoconazole; as well as triazoles like fluconazole, itraconazole and voriconazole.

The only difference between the two groups is the imidazoles contain an imidazole ring, while triazoles contain triazole rings.

These medications work by inhibiting the fourteen-alpha-demethylase enzyme.

However, they also inhibit human cytochrome P450 enzymes to a lesser degree.


Azoles are synthetic antifungals with broad spectrum activity against various fungal infections. Azoles bind to the ergosterol molecule in the fungal cell membrane and cause holes to form, which damages the cell membrane and eventually kills the fungus. Examples of azoles include drugs like clotrimazole, fluconazole, and itraconazole. Some of the side effects of azoles include nausea and vomiting, gynecomastia, and hepatotoxicity.


  1. "Katzung & Trevor's Pharmacology Examination and Board Review,12th Edition" McGraw-Hill Education / Medical (2018)
  2. "Rang and Dale's Pharmacology" Elsevier (2019)
  3. "Goodman and Gilman's The Pharmacological Basis of Therapeutics, 13th Edition" McGraw-Hill Education / Medical (2017)
  4. "Therapeutic tools for oral candidiasis: Current and new antifungal drugs" Medicina Oral Patología Oral y Cirugia Bucal (2019)
  5. "Adverse interactions between antifungal azoles and vincristine: review and analysis of cases" Mycoses (2011)

Copyright © 2023 Elsevier, its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Cookies are used by this site.

USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.