[Rational use of antimycotics against yeast infections]

Area of Science:

• Clinical Medicine
• Mycology
• Pharmacology

Background:

• Differentiating yeast colonization from true infection in clinical settings is difficult.
• This diagnostic challenge complicates the clear separation of preventive and therapeutic antifungal use.
• The limited number of available antifungal agents compared to antibacterials presents a therapeutic challenge.

Purpose of the Study:

• To review the use of antifungals for prophylaxis and therapy in yeast infections.
• To compare the properties and efficacy of different antifungal drug classes, specifically polyenes and azoles.
• To highlight the pharmacokinetic and toxicologic advantages of azoles, such as fluconazole, over polyenes like amphotericin B.

Main Methods:

• Review of existing literature on antifungal agents.
• Comparison of absorption, distribution, and toxicity profiles of polyenes (amphotericin B, nystatin) and azoles (fluconazole, itraconazole).
• Discussion of factors influencing drug absorption, such as gastric pH, and drug distribution to various body sites, including cerebrospinal fluid (CSF).

Main Results:

• Azoles are absorbed and distributed to remote sites, unlike non-resorbable polyenes.
• Fluconazole absorption is independent of gastric pH, offering an advantage over itraconazole in certain patient populations.
• Systemic amphotericin B has disadvantages including toxicity and insufficient concentrations in some sites (kidney, CSF); azoles generally have better pharmacologic and toxicologic properties.

Conclusions:

• Azole antifungals demonstrate superior pharmacokinetic and toxicologic profiles for treating yeast infections compared to systemic polyenes.
• While antifungal resistance is possible, it is currently rare, obviating the need for routine susceptibility testing.
• Certain Candida species, such as Candida glabrata and Candida krusei, exhibit primary resistance to fluconazole.