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 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.

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.

The FDA has approved luliconazole (Luzu Cream, 1% – Valeant) for treatment of tinea pedis, tinea cruris, and tinea corporis infections.

A Medical Letter reader recently received a diagnosis of athlete’s foot and a prescription for Naftin gel, for which his pharmacy charged $145, and his insurance company required a $70 copay because this formulation was not included in its formulary. Do patients need to pay prices like these to treat tinea pedis?

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

Use of a selective serotonin reuptake inhibitor (SSRI) is common in women taking tamoxifen (Nolvadex, and others) for breast cancer, both to treat depression and to decrease hot flashes. However, tamoxifen must be metabolized by CYP2D6 to become pharmacologically fully active (MJ Higgins et al. J Natl Compr Canc Netw 2009; 7:203), and the SSRIs fluoxetine (Prozac, and others) and paroxetine (Paxil, and others) are strong inhibitors of CYP2D6. Sertraline (Zoloft, and others) inhibits CYP2D6 to a lesser extent. Citalopram (Celexa, and others) and escitalopram (Lexapro), the 2 other SSRIs approved for treatment of depression, are only weak inhibitors of CYP2D6.

Two observational studies presented at a recent meeting of the American Society of Clinical Oncology (45th annual meeting, May 29-June 2, 2009, Orlando, FL abstracts CRA508, CRA509) examined the effect of strong inhibitors of CYP2D6 on the success rate of tamoxifen in preventing recurrence of breast cancer. One found that women who took fluoxetine, paroxetine or sertraline (or bupropion, duloxetine, terbinafine, quinidine or long-term diphenhydramine) with tamoxifen had a higher 2-year recurrence rate (13.9% vs. 7.5%). The other study found no association between cancer recurrence and use of a CYP2D6 inhibitor.

There is no good evidence that any one SSRI is more effective than any other for treatment of depression. For women who are taking tamoxifen and need to begin treatment with an SSRI to treat depression, citalopram or escitalopram might be the safest choice (Treat Guidel Med Lett 2006; 4:35). Use of an SSRI to treat hot flashes in women taking tamoxifen should probably be reconsidered.

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The drugs of choice for treatment of some fungal infections are listed in the tables. Some of the indications and dosages recommended here have not been approved by the FDA. Other guidelines are available from the Infectious Diseases Society of America (www.idsociety.org).

The drugs of choice for treatment of some fungal infections are listed in the table that begins on page 8. Some of the indications and dosages recommended here have not been approved by the FDA.

Sertaconazole nitrate (Ertaczo - OrthoNeutrogena), an imidazole antifungal similar to clotrimazole and miconazole, has been approved by the FDA as a 2% cream for topical treatment of interdigital tinea pedis infection. It has been available in Europe for many years.

Ciclopirox nail lacquer (Penlac - Dermik) has been approved by the FDA for treatment of mild-to-moderate onychomycosis due to Trichophyton rubrum, without involvement of the lunula. The drug has been available for many years as a lotion and cream (Loprox) for treatment of cutaneous fungal infection

Butenafine hydrochloride 1% cream (Mentax - Penederm), a benzylamine antifungal drug similar to the allylamines terbinafine (Lamisil) and naftifine (Naftin), is now available in the USA for topical treatment of tinea pedis, tinea corporis and tinea cruris.

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 1% cream (Lamisil - Sandoz), an allylamine synthetic antifungal drug chemically related to naftifine (Naftin - Medical Letter, 30:98, 1988), is now available in the USA for topical treatment of tinea pedis, tinea cruris, and tinea corporis infections. An oral formulation is available in Europe and is under investigation here.