Which antifungal is considered first-line for systemic candidiasis?

Fluconazole is considered the first-line treatment for systemic candidiasis due to its effectiveness against a range of Candida species, particularly Candida albicans, which is one of the most common pathogens responsible for invasive candidiasis. It has a well-established safety profile, good oral bioavailability, and favorable pharmacokinetics, allowing for effective treatment of infections without requiring parenteral administration in many cases.

Fluconazole's mechanism of action involves inhibiting the synthesis of ergosterol, an essential component of fungal cell membranes, which disrupts membrane integrity and leads to cell death. Its efficacy in treating candidemia and other systemic infections caused by susceptible strains makes it the preferred choice.

While other agents like amphotericin B, itraconazole, and voriconazole have important roles in treating specific fungal infections, they are often reserved for cases where fluconazole is not effective due to resistance, for treatment of more severe infections, or for other specific indications. Moreover, amphotericin B, while effective, has significant side effects and must be administered intravenously, which can limit its use. Itraconazole and voriconazole, while useful for certain types of fungal infections, are generally not the first choice for candidiasis.