What is the best antibiotic for onychomycosis (fungal infection of the nail)?

From the Guidelines

Terbinafine is the best antibiotic for onychomycosis, due to its higher efficacy and tolerability compared to other options like itraconazole. The British Association of Dermatologists' guidelines for the management of onychomycosis 2014 recommend terbinafine as the first choice of treatment, unless there are contraindications 1.

Key Points to Consider

• Terbinafine is licensed at a dose of 250 mg per day for 6 weeks in fingernail and 12–16 weeks in toenail infection.
• Itraconazole is an alternative option, but it has been shown to have lower efficacy rates compared to terbinafine, with complete cure rates of 26% compared to 55% for terbinafine at 72 weeks follow-up 1.
• Patients should be re-evaluated 3–6 months after treatment initiation and further treatment should be given if the disease persists.
• It is essential to monitor liver function tests during treatment due to the rare risk of hepatotoxicity associated with terbinafine.

Treatment Outcomes

• Complete nail clearing takes time, as the healthy nail needs to grow out, which can take 4-6 months for fingernails and 12-18 months for toenails.
• Mycological and clinical relapse is significantly higher in patients treated with itraconazole compared to terbinafine, with relapse rates of 53% and 48% for itraconazole, and 23% and 21% for terbinafine, respectively 1.

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 Terbinafine tablets are an allylamine antifungal indicated for the treatment of onychomycosis of the toenail or fingernail due to dermatophytes (tinea unguium) (1)

The best antibiotic for onychomycosis is Terbinafine.

• Key points:
  • Terbinafine is an antifungal medication, not an antibiotic.
  • It is indicated for the treatment of onychomycosis of the toenail or fingernail due to dermatophytes.
  • The treatment duration is usually 6 weeks for fingernail onychomycosis and 12 weeks for toenail onychomycosis 2, 2, 2.

From the Research

Treatment Options for Onychomycosis

• Terbinafine is a highly effective treatment for onychomycosis, particularly for dermatophyte infections 3, 4, 5.
• The efficacy of terbinafine has been demonstrated in several studies, with mycologic cure rates ranging from 62-91% 3, 4, 5, 6.
• Terbinafine has been shown to be more effective than other antifungal agents, such as itraconazole, fluconazole, and griseofulvin, in the treatment of dermatophyte onychomycosis 3, 4.

Special Populations

• Terbinafine is effective and well-tolerated in high-risk populations, including patients with diabetes mellitus, HIV-positive patients, and those receiving immunosuppressive therapy 6.
• Terbinafine has been shown to be effective in treating nondermatophyte onychomycosis, with mycologic cure rates ranging from 64-91% 6.

Combination Therapy

• Combining terbinafine with topical antifungal agents, such as amorolfine, may enhance treatment efficacy and provide additive or synergistic effects 7.
• The use of terbinafine in combination with other antifungal agents may be beneficial in patients with difficult-to-treat onychomycosis, such as those with nondermatophyte infections 7.

Safety and Tolerability

• Terbinafine is generally well-tolerated, with most adverse events being transient and mild to moderate in severity 3, 4, 5.
• Terbinafine has a low potential for drug interactions, making it a safe treatment option for patients with onychomycosis 3, 4.