Pulsed versus continuous terbinafine dosing in the treatment of dermatophyte onychomycosis

Effectiveness and safety of oral terbinafine for dermatophyte distal subungual onychomycosis

INTRODUCTION

Terbinafine has been a cornerstone in dermatophyte infection treatment. Despite its global efficacy, the emergence of terbinafine resistance raises concerns, requiring ongoing vigilance.

AREAS COVERED

This paper focuses on evaluating the efficacy and safety of terbinafine in treating dermatophyte toenail infections. Continuous and pulse therapies, with a 24-week continuous regimen and a higher dosage of 500 mg/day have demonstrated superior efficacy to the FDA approved regimen of 250 mg/day x 12 weeks. Pulse therapies, though showing comparable effectiveness, present debates with regards to their efficacy as conflicting findings have been reported. Safety concerns encompass hepatotoxicity, gastrointestinal, cutaneous, neurologic, hematologic and immune adverse-effects, and possible drug interactions, suggesting the need for ongoing monitoring.

EXPERT OPINION

Terbinafine efficacy depends on dosage, duration, and resistance patterns. Continuous therapy for 24 weeks and a dosage of 500 mg/day may enhance outcomes, but safety considerations and resistance necessitate individualized approaches. Alternatives, including topical agents and alternative antifungals, are to be considered for resistant cases. Understanding the interplay between treatment parameters, adverse effects, and resistance mechanisms is critical for optimizing therapeutic efficacy while mitigating resistance risks. Patient education and adherence are vital for early detection and management of adverse effects and resistance, contributing to tailored and effective treatments.

Improving Cure Rates in Onychomycosis

Background:

Onychomycosis is a persistent fungal nail infection that is notoriously hard to treat. Approximately 20% to 25% of patients with onychomycosis do not respond to treatment, and 10% to 53% of patients relapse. As such, successful treatment is imperative for long-term disease management.

Objective:

To identify ways to improve cure rates for onychomycosis.

Method:

The literature on onychomycosis treatment and recurrence was reviewed to summarize treatment approaches and suggest strategies to increase cure rates.

Results and Conclusion:

To improve treatment success in onychomycosis, we suggest the following measures be followed: (1) onychomycosis must be correctly diagnosed, (2) the treatment regimen should be tailored to the individual patient, (3) the efficacy of antifungals must be maximized, and (4) recurrence must be prevented.

An update on treatment of onychomycosis

Onychomycosis (OM) is a fungal infection of the nail plate or nail bed which is highly prevalent in the general population and also responsible for significant morbidity. The condition needs to be treated in view of the physical and emotional handicap it produces. The peculiarities of the nail apparatus in health and disease lead to difficulties in being able to successfully treat this condition. Hence, the very same antifungals which produce high cure rates in skin infections are rendered less efficacious in nail disease. Low cure rates and high relapse rates even with highly efficacious antifungals have lead to an increasing interest in exploring newer treatment options which can ensure drug penetration, drug persistence, mycological cure and effective prevention of relapse. The current review aims to summarize our current status of knowledge about the treatment options for OM. It also summarizes the newer areas of research especially with respect to devices related therapies; physical measures to enhance penetration through nail; and development and evaluation of synergistic combinations.

The safety of oral antifungal treatments for superficial dermatophytosis and onychomycosis: a meta-analysis

PURPOSE

We estimated the absolute risks of treatment termination and incidence of adverse liver outcomes among all commonly used oral antifungal treatments for superficial dermatophytosis and onychomycosis.

METHODS

MEDLINE, EMBASE, and Cochrane Library were searched to identify randomized and nonrandomized controlled trials, case series, and cohort studies published before December 31, 2005. Two reviewers independently applied selection criteria, performed quality assessment, and extracted data. Treatment arms with the same regimen in terms of drug, type (continuous or intermittent), and dosage were combined to estimate the risk of an outcome of interest.

RESULTS

We identified 122 studies with approximately 20,000 enrolled patients for planned comparison. The pooled risks (95% confidence intervals) of treatment discontinuation resulting from adverse reactions for continuous therapy were 3.44% (95% confidence interval [CI], 2.28%-4.61%) for terbinafine 250 mg/day; 1.96% (95% CI, 0.35%-3.57%) for itraconazole 100 mg/day; 4.21% (95% CI, 2.33%-6.09%) for itraconazole 200 mg/day; and 1.51% (95% CI, 0%-4.01%) for fluconazole 50 mg/day. For intermittent therapy, the pooled risks were as follows: pulse terbinafine: 2.09% (95% CI, 0%-4.42%); pulse itraconazole: 2.58% (95% CI, 1.15%-4.01%); intermittent fluconazole 150 mg/week: 1.98% (95% CI, 0.05%-3.92%); and intermittent fluconazole 300 to 450 mg/week: 5.76% (95% CI, 2.42%-9.10%). The risk of liver injury requiring termination of treatment ranged from 0.11% (continuous itraconazole 100 mg/day) to 1.22% (continuous fluconazole 50 mg/day). The risk of having asymptomatic elevation of serum transaminase but not requiring treatment discontinuation was less than 2.0% for all treatment regimens evaluated.

CONCLUSION

Oral antifungal therapy against superficial dermatophytosis and onychomycosis, including intermittent and continuous terbinafine, itraconazole, and fluconazole, was associated with a low incidence of adverse events in an immunocompetent population.

Toenail onychomycosis: current and future treatment options

Onychomycosis is a common disease affecting as much as 8% of the general population. Treatment of onychomycosis is challenging, complicated by low cure rates and relatively high relapse rates. This paper reviews the efficacy of current oral, topical, and surgical treatment options. Currently, the treatment of choice for toenail onychomycosis is oral terbinafine because of its high efficacy, low relapse rates, and cost-effectiveness. Oral itraconazole or fluconazole could be considered for infections caused by Candida. Topical therapies may be a useful adjunct to these systemic therapies, but are less effective when used alone. More research is needed to determine the best measures for preventing reinfection.

Therapies for Onychomycosis: A Review

Onychomycosis, a chronic fungal infection of the nail, can be treated using various modalities. Surgical, chemical, topical, and oral methods are reviewed in this article, with an emphasis on the three systemic treatments approved by the US Food and Drug Administration: terbinafine, itraconazole, and griseofulvin.