Itraconazole (Sporanox - Janssen), an antifungal triazole, has been approved by the US Food and Drug Administration (FDA) for oral treatment of histoplasmosis and blastomycosis. These two endemic mycoses occur both in normal hosts and in immunocompromised patients, such as those with AIDS (RW Bradsher, Clin Infect Dis, 14:S82, 1992; LJ Wheat, Clin Infect Dis, 14:S91, 1992).

Itraconazole (Sporanox - Janssen), an oral antifungal triazole that has been available in the USA since 1992 for treatment of deep fungal infections (Medical Letter, 35:7, 1993), is now being marketed for treatment of dermatophyte infections of the toenails, with or without fingernail involvement.

Terbinafine (Lamisil - Sandoz), an allylamine synthetic antifungal, previously available in the USA in a topical formulation (Medical Letter, 35:76, 1993) has now been marketed for oral use in the treatment of fungal nail infections caused by dermatophytes. Oral terbinafine has been available in Europe since 1992.

Onychomycosis is caused most commonly by Trichophyton rubrum or T. mentagrophytes. About 10% of all persons worldwide and 40% of those ≥60 years old are believed to have the disease. Risk factors include older age, diabetes, poor peripheral circulation, smoking, HIV infection, psoriasis, and immunosuppression. Left untreated, onychomycosis can cause nail plate destruction, ingrown nails, and (particularly in patients with diabetes) secondary infections. Guidelines on treatment of onychomycosis have been published.

The drugs of choice for treatment of fungal infections are listed in the table that begins on page 62. Some of the indications and dosages recommended here have not been approved by the FDA. More detailed guidelines for some of these infections are available online from the Infectious Diseases Society of America (www.idsociety.org).

Caspofungin acetate(Cancidas) is the first of a new class of antifungals, the echinocandins. It has been approved by the FDA for treatment of invasive aspergillosis in patients who fail to respond to or are unable to tolerate other antifungal drugs such as amphotericin B and itraconazole.

The FDA has approved efinaconazole 10% solution (Jublia – Valeant) for topical treatment of toenail onychomycosis due to Trichophyton rubrum and/or Trichophyton mentagrophytes. It is the first topical triazole antifungal drug to be approved for this indication. A topical oxaborole antifungal solution, tavaborole 5% (Kerydin – Anacor), also recently approved by the FDA for the same indication will be reviewed in a future issue.

Voriconazole (Vfend -- Pfizer), an antifungal triazole structurally related to fluconazole (Diflucan) with a spectrum of action similar to that of itraconazole, has been approved by the FDA for primary treatment of invasive aspergillosis and for refractory infection with Scedosporium apiospermum (the asexual form of Pseudallescheria boydii) or Fusarium spp.

The FDA has approved tavaborole 5% solution (Kerydin – Anacor Pharmaceuticals) for topical treatment of toenail onychomycosis due to Trichophyton rubrum or Trichophyton mentagrophytes. It is the first oxaborole antifungal drug to be approved for this indication.

Posaconazole (Noxafil - Schering-Plough), an oral azole antifungal with a chemical structure similar to that of itraconazole (Sporanox), has been approved by the FDA to prevent Candida and Aspergillus infections in severely immunocompromised patients and for treatment of oropharyngeal candidiasis. It is likely also to be used off-label for treatment of other fungal infections, including those caused by Mucor and other Zygomycetes.