From the Guidelines
To treat resistant toe fungus, start with a combination of oral and topical antifungal medications, with terbinafine (250 mg daily for 12 weeks) being the most effective option, as shown in the British Association of Dermatologists' guidelines for the management of onychomycosis 2014 1. When considering treatment options, it's essential to weigh the efficacy and tolerability of different antifungal medications.
- Terbinafine has been shown to have higher efficacy rates compared to itraconazole, with complete cure rates of 55% versus 26% in a multicentre, randomized trial 1.
- Itraconazole is an alternative option, with a recommended dose of 200 mg per day for 12 weeks continuously, or as pulse therapy at a dose of 400 mg per day for 1 week per month 1.
- Fluconazole may be a useful alternative in patients unable to tolerate terbinafine or itraconazole, with a recommended dose of 450 mg per week for 3 months in fingernail infections and for at least 6 months in toenail infections 1. In addition to oral medication, topical treatments such as ciclopirox 8% nail lacquer or efinaconazole 10% solution can be applied to the affected nails. For severe cases, consider asking your doctor about adding periodic debridement (professional removal of infected nail tissue) to improve medication penetration, as treatment failure is often due to kinetic factors, such as subungual dermatophytoma 1. It's crucial to keep nails short, dry, and clean, wearing breathable footwear and changing socks daily to prevent the spread of infection. The combination approach works by attacking the fungus systemically through oral medication while simultaneously treating it locally with topicals, and complete treatment typically takes 6-12 months since nails grow slowly, and you should continue treatment until a healthy nail has completely grown out.
From the FDA Drug Label
Terbinafine tablets, USP are indicated for the treatment of onychomycosis of the toenail or fingernail due to dermatophytes (tinea unguium). The treatment for resistant toe fungus is terbinafine (PO), with a recommended dosage of one 250 mg tablet once daily for 12 weeks for treatment of toenail onychomycosis 2.
- Key points:
- The optimal clinical effect is seen some months after mycological cure and cessation of treatment due to the time period required for outgrowth of healthy nail.
- Patients should be advised to immediately report to their physician any symptoms of persistent nausea, anorexia, fatigue, vomiting, right upper abdominal pain, jaundice, dark urine or pale stools.
- Important considerations: Prior to initiating treatment, appropriate nail specimens for laboratory testing (KOH preparation, fungal culture, or nail biopsy) should be obtained to confirm the diagnosis of onychomycosis 2.
From the Research
Treatment Options for Resistant Toe Fungus
- Oral antifungals such as terbinafine, itraconazole, and fluconazole are effective for the treatment of moderate to severe onychomycosis 3, 4, 5
- Topical antifungals like 1% terbinafine cream, ciclopirox 8% nail lacquer, efinaconazole 10% solution, and tavaborole 5% solution can be used for mild to moderate disease 6, 7, 5
- Fractional CO2 laser with topical 1% terbinafine cream is an effective and safe method for inducing nail clearance in onychomycosis, with efficacy similar to itraconazole pulse therapy 6
- Chemical nail destruction with a combination of urea and bifonazole, followed by treatment with an antifungal ointment, can be used when the nail is markedly thickened 7
- Surgical nail avulsion carries a risk of local infection and permanent nail dystrophy, and should be considered as a last resort 7
Considerations for Treatment
- The choice of treatment should be based on the severity of the disease, the infecting pathogen, medication safety, efficacy and cost, and patient age, comorbidities, medication history, and likelihood of compliance 3, 5
- Laboratory testing of liver function tests should be performed prior to the administration of any oral antifungals, especially when clinically indicated 3
- Antifungal susceptibility testing should be considered in cases of treatment failure 3
- Patients should be counseled on an appropriate plan to minimize recurrence risk following effective antifungal therapy 5