Antifungal agents. Part II. The azoles

C L Terrell1

  • 1Division of Allergy and Outpatient Infectious Disease and Internal Medicine, Mayo Clinic Rochester, Minnesota 55905, USA.

Mayo Clinic Proceedings
|February 13, 1999
PubMed

Insights

New antifungal drugs like fluconazole and itraconazole have largely replaced older treatments for systemic fungal infections, offering improved efficacy and safety profiles. Research continues for even newer antifungal agents.

Area of Science:

  • Mycology
  • Pharmacology
  • Infectious Diseases

Background:

  • Systemic fungal infections were primarily treated with amphotericin B and flucytosine before 1978.
  • The introduction of imidazoles (miconazole, ketoconazole) marked advancements in antifungal therapy.
  • Ketoconazole was a widely used oral antifungal for a decade due to limited alternatives.

Purpose of the Study:

  • To review the evolution of antifungal drug therapy for systemic fungal infections.
  • To compare the efficacy and safety profiles of older and newer antifungal agents.
  • To highlight the therapeutic roles of triazoles (fluconazole, itraconazole).

Main Methods:

  • Literature review of antifungal drug development and clinical use.
  • Comparative analysis of pharmacologic properties, efficacy, and toxicity.
  • Examination of treatment guidelines and therapeutic outcomes.

Main Results:

  • Fluconazole offers improved safety and efficacy over ketoconazole, with better cerebrospinal fluid penetration.
  • Itraconazole, despite drug interactions, is valuable for specific infections like sporotrichosis and aspergillosis.
  • Itraconazole has replaced ketoconazole for certain endemic mycoses and is effective in cryptococcosis and coccidioidomycosis.

Conclusions:

  • The development of triazoles (fluconazole, itraconazole) has significantly advanced systemic fungal infection treatment.
  • Fluconazole and itraconazole represent major improvements over older antifungal agents.
  • Ongoing research aims to develop novel antifungal agents to combat resistant fungal strains.

Related Concept Videos

Fungal Group Zygomycota01:29

Fungal Group Zygomycota

Zygomycota, previously classified as a distinct fungal group, are primarily terrestrial, saprophytic molds that play a crucial role as decomposers. Recent phylogenetic studies have revealed that these fungi are now divided into two major clades — Mucoromycota, which includes many symbiotic species, and Zoopagomycota, which primarily consists of parasitic and pathogenic fungi. These groups exhibit distinct ecological roles and reproductive strategies while sharing key structural and...
Fungal Phylum Ascomycota01:28

Fungal Phylum Ascomycota

Phylum Ascomycota, a major division within the subkingdom Dikarya, comprises a diverse range of fungal species, including both unicellular yeasts and filamentous molds such as Aspergillus and Penicillium. These fungi thrive in a variety of habitats, from aquatic ecosystems to terrestrial environments, playing crucial ecological and economic roles.Morphology and ReproductionThe defining characteristic of Ascomycetes, commonly referred to as sac fungi, is the ascus—a sac-like structure that...
Candidiasis01:20

Candidiasis

Candidiasis is a fungal infection caused by opportunistic species of Candida. It can affect various anatomical sites, including the skin, oral cavity, nails, and genitourinary tract. Among its forms, vaginal candidiasis is the most common type of mucosal infection. It typically results from the overgrowth of Candida albicans in the vaginal mucosa. Under normal conditions, C. albicans exists as a commensal organism within the vaginal microbiota, regulated by the dominance of lactobacilli, which...
Antifungal Agents01:15

Antifungal Agents

Amphotericin B is a broad-spectrum antifungal agent that exploits structural differences between fungal and mammalian cell membranes. Its amphipathic structure—featuring a hydrophobic polyene-lactone ring and a hydrophilic region containing mycosamine and carboxylic acid groups—enables selective binding to ergosterol, a sterol predominantly found in fungal plasma membranes. This selective interaction underlies the drug’s antifungal activity, although weak binding to cholesterol contributes to...
Anthelminthic Agents01:15

Anthelminthic Agents

Anthelmintic drugs differ significantly from antiparasitic therapies targeting protozoa, primarily due to differences in parasite biology. Whereas most protozoal treatments act on proliferating cells, anthelmintics are typically directed against mature, nonproliferative helminths. The therapeutic approach considers the helminth's reliance on neuromuscular coordination, glucose metabolism, and microtubular integrity for survival, reproduction, and localization within the host. Most anthelmintics...
Antiprotozoal Agents01:21

Antiprotozoal Agents

Leishmaniasis is a widespread parasitic disease caused by several Leishmania species. It affects millions of people each year and remains a major public health problem in endemic regions. First-line treatment relies on pentavalent antimonials, including meglumine antimoniate and sodium stibogluconate. Even so, how these drugs work has not been fully clear, especially their interaction with parasite-specific biochemical pathways. One key target is trypanothione reductase (TR), an enzyme that...