Onychomycosis Treatment Guidelines

First-Line Treatment

The British College of Dermatology recommends oral terbinafine 250 mg daily as the first-line treatment for onychomycosis involving both fingernails and toenails, with a treatment duration of 6 weeks for fingernails and 12 weeks for toenails, taken concurrently when both are infected 1
For simultaneous fingernail and toenail involvement, the British College of Dermatology suggests treating with terbinafine 250 mg once daily for 12 weeks, which will adequately cover the fingernail treatment period 1, 2
Patients should be re-evaluated 3-6 months after treatment initiation and provided with additional treatment if the disease persists, as recommended by the British College of Dermatology 1, 2

Terbinafine demonstrates superior efficacy compared to itraconazole, with complete cure rates of 55% versus 26% at 72 weeks, and long-term mycological cure without retreatment of 46% versus 13% at 5 years, according to the British College of Dermatology 1
The British College of Dermatology notes that terbinafine is fungicidal against dermatophytes with very low minimum inhibitory concentrations, making it more effective than the fungistatic azoles 2
Terbinafine has minimal drug-drug interactions compared to azole antifungals, with only cytochrome P450 2D6 substrates requiring caution, as stated by the British College of Dermatology 1, 2, 3

If terbinafine is contraindicated or not tolerated, the British College of Dermatology recommends using itraconazole 200 mg daily for 12 weeks continuously, or pulse therapy at 400 mg daily for 1 week per month, as a second-line alternative 1
Itraconazole is less effective than terbinafine but remains superior to fluconazole and griseofulvin, according to the British College of Dermatology 1
The British College of Dermatology suggests that fluconazole 450 mg once weekly can be used as a third-line alternative when both terbinafine and itraconazole cannot be tolerated, with a treatment duration of 3 months for fingernails and at least 6 months for toenails 1, 5
Fluconazole has lower efficacy but offers convenient once-weekly dosing, and requires dose adjustment in renal impairment, as noted by the British College of Dermatology 1, 5

The British College of Dermatology recommends terbinafine for diabetic patients due to its low risk of drug interactions and hypoglycemia, and because itraconazole is contraindicated in heart failure, which is more prevalent in diabetics 4
Terbinafine is preferred over itraconazole for immunosuppressed patients due to fewer interactions with antiretrovirals and immunosuppressive medications, according to the British College of Dermatology 4
For pediatric patients, the British College of Dermatology suggests terbinafine dosing is weight-based, with a treatment duration of 6 weeks for fingernails and 12 weeks for toenails 4