What are the treatment options for onychomycosis (fungal infection of the toenail) and their comparative efficacies, including the efficacy of Listerine (containing benzalkonium chloride and other ingredients) application?

From the Guidelines

Toenail fungus infections are most effectively treated with oral antifungals, specifically terbinafine, which has been shown to have higher efficacy and tolerability compared to itraconazole. The various options for treating toenail fungus infections include topical antifungals, oral medications, and home remedies, with varying degrees of effectiveness. For mild to moderate infections, over-the-counter topical treatments like clotrimazole or ciclopirox can be applied directly to the affected nail daily for several months, though they have modest success rates. Prescription oral antifungals such as terbinafine (250mg daily for 12-16 weeks) or itraconazole (200mg per day for 12 weeks continuously, or alternatively as pulse therapy) are more effective, with cure rates of 50-80%, but may cause side effects including liver damage 1. Some key points to consider when treating toenail fungus infections include:

• Terbinafine is licensed at a dose of 250 mg per day for 6 weeks in fingernail and 12–16 weeks in toenail infection 1.
• Itraconazole is licensed at a dose of 200 mg per day for 12 weeks continuously, or alternatively as pulse therapy at a dose of 400 mg per day for 1 week per month 1.
• Several large studies demonstrate higher efficacy rates for terbinafine in comparison with itraconazole, with complete cure rates of 55% for terbinafine and 26% for pulsed itraconazole 1. Regarding Listerine, there is limited scientific evidence supporting its effectiveness against toenail fungus, and it should not be considered a primary treatment option. While it contains ingredients with some antimicrobial properties, these aren't specifically proven to treat fungal nail infections effectively. Fungal nail infections require consistent, long-term treatment regardless of the method chosen, and maintaining good foot hygiene, keeping nails trimmed, wearing breathable footwear, and using antifungal powders can help prevent recurrence.

From the FDA Drug Label

1 INDICATIONS AND USAGE Terbinafine tablets, USP are indicated for the treatment of onychomycosis of the toenail or fingernail due to dermatophytes (tinea unguium).

INDICATIONS AND USAGE (To understand fully the indication for this product, please read the entire INDICATIONS AND USAGE section of the labeling.) Ciclopirox Topical Solution, 8%, (Nail Lacquer), as a component of a comprehensive management program, is indicated as topical treatment in immunocompetent patients with mild to moderate onychomycosis of fingernails and toenails without lunula involvement, due to Trichophyton rubrum

The various options for toenail fungus infections include:

• Terbinafine (PO): indicated for the treatment of onychomycosis of the toenail or fingernail due to dermatophytes (tinea unguium) 2
• Ciclopirox (TOP): indicated as topical treatment in immunocompetent patients with mild to moderate onychomycosis of fingernails and toenails without lunula involvement, due to Trichophyton rubrum 3 Their comparative efficacies are:
• Terbinafine (PO): no direct comparison with other treatments in the provided label 2
• Ciclopirox (TOP):
  • Complete cure: 5.5% and 8.5% in two studies 3
  • Almost clear: 6.5% and 12% in two studies 3
  • Negative mycology: 29% and 36% in two studies 3 There is no information in the provided labels about the efficacy of Listerine application for toenail fungus treatment.

From the Research

Treatment Options for Toenail Fungus Infections

• Oral antifungal medications, such as terbinafine and azoles, have been shown to be effective in treating toenail fungus infections 4, 5
• Topical antifungal treatments, including amorolfine, ciclopirox, tavaborole, and efinaconazole, can be used to treat mild to moderate toenail fungus infections 6, 7
• Nail avulsion and debridement by chemical or surgical procedures are also available treatment options 8
• Device-based therapies are another treatment option for onychomycosis 8

Comparative Efficacies of Treatment Options

• Terbinafine has been shown to be more effective than azoles in achieving clinical and mycological cure 4, 5
• Azoles have been shown to be more effective than griseofulvin in achieving clinical and mycological cure 4
• Topical treatments have been shown to be effective in treating mild to moderate toenail fungus infections, but may not be as effective as oral treatments 7

Listerine Application for Toenail Fungus

• There is no evidence to suggest that Listerine application is an effective treatment for toenail fungus infections 4, 5, 6, 8, 7
• The available evidence suggests that oral and topical antifungal medications are more effective in treating toenail fungus infections than other treatment options, including Listerine application

Adverse Events and Safety

• Oral antifungal medications, such as terbinafine and azoles, have been associated with adverse events, including gastrointestinal symptoms, infections, and headache 4
• Topical antifungal treatments have been associated with adverse events, including skin irritation and allergic reactions 7
• The safety and efficacy of treatment options should be carefully considered when selecting a treatment for toenail fungus infection 4, 8