What's New in Onychomycosis Oral Therapy and Resistance?

The discussion on onychomycosis oral therapy highlights the significance of terbinafine, which has been considered the gold standard for treating this condition since its FDA approval in 1992. Despite its efficacy and minimal side effects, concerns about terbinafine resistance have emerged, particularly due to mutations in the squalene epoxidase gene, leading to a binding issue that can render the drug ineffective. Current research indicates that about 3% of patients may show these mutations, primarily in Trichophyton rubrum. However, not all mutations affect drug effectiveness, and only a fraction of patients with mutations will exhibit complete resistance. In cases of terbinafine resistance, alternative therapies like itraconazole, fluconazole, or off-label options such as voriconazole and posaconazole can be considered, with studies demonstrating similar effectiveness to terbinafine. Preventive measures are also critical, as relapses are common within two years post-treatment. Topical agents like efinaconazole may help in preventing recurrence, and proper hygiene regarding footwear and family treatment is emphasized to avoid reinfection. Overall, while terbinafine remains the mainstay for onychomycosis, understanding resistance patterns and exploring alternative treatments and preventative strategies are becoming increasingly important in managing this condition.