Terbinafine in onychomycosis of the toenail: a novel treatment protocol

Relative impact of traditional vs. newer oral antifungals for dermatophyte toenail onychomycosis: a network meta-analysis study

BACKGROUND

There is a paucity of evidence regarding the relative therapeutic efficacy of treatments for onychomycosis.

OBJECTIVES

We determined the relative efficacy of monotherapies for dermatophyte toenail onychomycosis with Bayesian network meta-analyses (NMAs).

METHODS

We searched PubMed, Scopus, EMBASE (Ovid) and CINAHL to identify studies that investigated the efficacy of monotherapy with oral antifungals for dermatophyte toenail onychomycosis in adults. In this paper, 'regimen' corresponds to a given agent and its dosage. The relative effects and surface under the cumulative ranking curve (SUCRA) values of the various regimens were estimated; evidence quality was assessed at the study level and across networks.

RESULTS

Data from 21 studies were used. Our two efficacy-related endpoints were: (i) mycological and (ii) complete cure at 1 year; safety--related endpoints were: (i) 1-year count of any adverse event (AE), (ii) 1-year odds of discontinuation due to any AE, (iii) 1-year odds of discontinuation due to liver issues. Thirty-five regimens were identified; the newer agents among these included posaconazole and oteseconazole. We compared the efficacy of newer regimens with traditional ones like 'terbinafine 250 mg daily for 12 weeks' and 'itraconazole 200 mg daily for 12 weeks. We found that an agent's dosage was associated with its efficacy; for example, the 1-year odds of mycological cure with terbinafine 250 mg daily for 24 weeks (SUCRA = 92.4%) were significantly greater than those of terbinafine 250 mg daily for 12 weeks (SUCRA = 66.3%) (odds ratio 2.62, 95% credible interval 1.57-4.54). We also found that booster regimens can increase efficacy. Our results showed that some triazoles could be more effective than terbinafine.

CONCLUSIONS

This is the first NMA study of monotherapeutic antifungals - and their various dosages - for dermatophyte toenail onychomycosis. Our findings could provide guidance for the selection of the most appropriate antifungal agent, especially amid the growing concerns about terbinafine resistance.

Race reporting and representation in onychomycosis clinical trials: A systematic review

BACKGROUND

Onychomycosis is the most common nail disease seen in clinical practice. Inclusion of diverse groups in onychomycosis clinical trials subjects is necessary to generalise efficacy data.

OBJECTIVES

We aimed to systematically review race and ethnicity reporting and representation, as well as, treatment outcomes in onychomycosis clinical trials.

METHODS

A PubMed search for onychomycosis clinical trials was performed in August 2020. Primary clinical trial data were included and post hoc analyses were excluded. Categorical variables were compared using chi-squared and Fisher's exact tests. Statistical significance was set at p < .05. Photos in articles were categorised by Fitzpatrick skin type.

RESULTS

Only 32/182 (17.5%) trials reported on race and/or ethnicity and only one trial compared treatment efficacy in different subgroups. Darker skin colours were infrequently depicted in articles. Topical treatment, location with ≥1 US-based site, industry funding type and publication date after 2000 were significantly associated with reporting of racial/ethnic data (p < .05 for all comparisons).

LIMITATIONS

Demographics on excluded subjects and methods of recruitment were not available. Assigning Fitzpatrick skin type is inherently subjective.

CONCLUSIONS

This study highlights a need for consistent reporting of races and ethnicities of onychomycosis clinical trial participants with subgroup analyses of treatment efficacies.

Oral antifungal therapies for toenail onychomycosis: a systematic review with network meta-analysis toenail mycosis: network meta-analysis

Aim: Toenail fungal infections account for half of all nail disease cases, and a highly negative impact on patient quality of life. Our aim was to compare the efficacy and safety of commercially available oral antifungals for onychomycosis.Methods: A systematic review was performed in PubMed and Scopus. Randomized controlled trials evaluating the effect of oral antifungals on mycological cure, discontinuation and adverse events were included. Network meta-analyses were built for each outcome. Results were reported as odds ratios (OR) with 95% credibility intervals (CrI). Ranking probabilities were calculated by surface under the cumulative ranking analysis (SUCRA).Results: We included 40 trials (n = 9568). Albaconazole 400 mg (OR 0.02 [95% CrI 0.01-0.07] versus placebo), followed by posaconazole 200-400 mg and terbinafine 250-350 mg were considered the best therapies (SUCRA probabilities over 75%). For the networks of discontinuation and individual adverse events, few significant differences among treatments were observed, but itraconazole 400 mg was considered the safest drug (SUCRA around 25%). Albaconazole 400 mg, posaconazole 200-400 mg, and terbinafine 250-350 mg were the most effective therapies for onychomycosis, while itraconazole 400 mg was the safest.Conclusion: The profile of albaconazole and posaconazole compared to current first-line therapies should be further investigated in well-designed trials.

Confirmatory Testing Prior to Initiating Onychomycosis Therapy Is Cost-Effective

Background:

Onychomycosis can be investigated by sampling. Information gleaned includes nail bed involvement, nail plate penetration, fungal viability, and species identification. Testing samples can confirm a diagnosis. While diagnostic testing is considered useful in directing therapy, a substantial number of clinicians do not confirm diagnosis prior to treatment.

Objectives:

The aim of this study is to quantify the benefit of confirmatory testing prior to treating toenail onychomycosis.

Methods:

The cost of mycological cure (negative potassium hydroxide and negative culture) and the cost-effectiveness of confirmatory testing were determined using the average cost of potassium hydroxide (KOH), culture, periodic acid–Schiff (PAS), efinaconazole, ciclopirox, terbinafine, and itraconazole. Costs were obtained through literature searches, public domain websites, and telephone surveys to local pharmacies and laboratories. To represent the potential risks of prescribing onychomycosis treatment, the costs associated with liver monitoring, potential life-threatening adverse events, and drug-drug interactions were obtained through public domain websites, published studies, and product inserts.

Results:

PAS was determined to be the most sensitive confirmatory test and KOH the least expensive. The overall cost of an incorrect diagnosis (no confirmatory test used) ranged between $350 and $1175 CAD per patient for treatment of 3 infected toenails. Comparatively, performing confirmatory testing prior to treatment decreases the overall cost to $320 to $930, depending on the therapy, physician, and test.

Conclusions:

It is preferred to diagnose onychomycosis prior to treatment. Furthermore, there are cost savings when confirmatory testing is performed before initiating treatment with both topical and oral antifungals in Canada.

Oral antifungal medication for toenail onychomycosis

BACKGROUND

Fungal infection of the toenails, also called onychomycosis, is a common problem that causes damage to the nail's structure and physical appearance. For those severely affected, it can interfere with normal daily activities. Treatment is taken orally or applied topically; however, traditionally topical treatments have low success rates due to the nail's physical properties. Oral treatments also appear to have shorter treatment times and better cure rates. Our review will assist those needing to make an evidence-based choice for treatment.

OBJECTIVES

To assess the effects of oral antifungal treatments for toenail onychomycosis.

SEARCH METHODS

We searched the following databases up to October 2016: the Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase, and LILACS. We also searched five trials registers and checked the reference lists of included and excluded studies for further references to relevant randomised controlled trials (RCTs). We sought to identify unpublished and ongoing trials by correspondence with authors and by contacting relevant pharmaceutical companies.

SELECTION CRITERIA

RCTs comparing oral antifungal treatment to placebo or another oral antifungal treatment in participants with toenail onychomycosis, confirmed by one or more positive cultures, direct microscopy of fungal elements, or histological examination of the nail.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 48 studies involving 10,200 participants. Half the studies took place in more than one centre and were conducted in outpatient dermatology settings. The participants mainly had subungual fungal infection of the toenails. Study duration ranged from 4 months to 2 years.We assessed one study as being at low risk of bias in all domains and 18 studies as being at high risk of bias in at least one domain. The most common high-risk domain was 'blinding of personnel and participants'.We found high-quality evidence that terbinafine is more effective than placebo for achieving clinical cure (risk ratio (RR) 6.00, 95% confidence interval (CI) 3.96 to 9.08, 8 studies, 1006 participants) and mycological cure (RR 4.53, 95% CI 2.47 to 8.33, 8 studies, 1006 participants). Adverse events amongst terbinafine-treated participants included gastrointestinal symptoms, infections, and headache, but there was probably no significant difference in their risk between the groups (RR 1.13, 95% CI 0.87 to 1.47, 4 studies, 399 participants, moderate-quality evidence).There was high-quality evidence that azoles were more effective than placebo for achieving clinical cure (RR 22.18, 95% CI 12.63 to 38.95, 9 studies, 3440 participants) and mycological cure (RR 5.86, 95% CI 3.23 to 10.62, 9 studies, 3440 participants). There were slightly more adverse events in the azole group (the most common being headache, flu-like symptoms, and nausea), but the difference was probably not significant (RR 1.04, 95% CI 0.97 to 1.12; 9 studies, 3441 participants, moderate-quality evidence).Terbinafine and azoles may lower the recurrence rate when compared, individually, to placebo (RR 0.05, 95% CI 0.01 to 0.38, 1 study, 35 participants; RR 0.55, 95% CI 0.29 to 1.07, 1 study, 26 participants, respectively; both low-quality evidence).There is moderate-quality evidence that terbinafine was probably more effective than azoles for achieving clinical cure (RR 0.82, 95% CI 0.72 to 0.95, 15 studies, 2168 participants) and mycological cure (RR 0.77, 95% CI 0.68 to 0.88, 17 studies, 2544 participants). There was probably no difference in the risk of adverse events (RR 1.00, 95% CI 0.86 to 1.17; 9 studies, 1762 participants, moderate-quality evidence) between the two groups, and there may be no difference in recurrence rate (RR 1.11, 95% CI 0.68 to 1.79, 5 studies, 282 participants, low-quality evidence). Common adverse events in both groups included headache, viral infection, and nausea.Moderate-quality evidence shows that azoles and griseofulvin probably had similar efficacy for achieving clinical cure (RR 0.94, 95% CI 0.45 to 1.96, 5 studies, 222 participants) and mycological cure (RR 0.87, 95% CI 0.50 to 1.51, 5 studies, 222 participants). However, the risk of adverse events was probably higher in the griseofulvin group (RR 2.41, 95% CI 1.56 to 3.73, 2 studies, 143 participants, moderate-quality evidence), with the most common being gastrointestinal disturbance and allergic reaction (in griseofulvin-treated participants) along with nausea and vomiting (in azole-treated participants). Very low-quality evidence means we are uncertain about this comparison's impact on recurrence rate (RR 4.00, 0.26 to 61.76, 1 study, 7 participants).There is low-quality evidence that terbinafine may be more effective than griseofulvin in terms of clinical cure (RR 0.32, 95% CI 0.14 to 0.72, 4 studies, 270 participants) and mycological cure (RR 0.64, 95% CI 0.46 to 0.90, 5 studies, 465 participants), and griseofulvin was associated with a higher risk of adverse events, although this was based on low-quality evidence (RR 2.09, 95% CI 1.15 to 3.82, 2 studies, 100 participants). Common adverse events included headache and stomach problems (in griseofulvin-treated participants) as well as taste loss and nausea (in terbinafine-treated participants). No studies addressed recurrence rate for this comparison.No study addressed quality of life.

AUTHORS' CONCLUSIONS

We found high-quality evidence that compared to placebo, terbinafine and azoles are effective treatments for the mycological and clinical cure of onychomycosis, with moderate-quality evidence of excess harm. However, terbinafine probably leads to better cure rates than azoles with the same risk of adverse events (moderate-quality evidence).Azole and griseofulvin were shown to probably have a similar effect on cure, but more adverse events appeared to occur with the latter (moderate-quality evidence). Terbinafine may improve cure and be associated with fewer adverse effects when compared to griseofulvin (low-quality evidence).Only four comparisons assessed recurrence rate: low-quality evidence found that terbinafine or azoles may lower the recurrence rate when compared to placebo, but there may be no difference between them.Only a limited number of studies reported adverse events, and the severity of the events was not taken into account.Overall, the quality of the evidence varied widely from high to very low depending on the outcome and comparison. The main reasons to downgrade evidence were limitations in study design, such as unclear allocation concealment and randomisation as well as lack of blinding.

Placebo cure rates in the treatment of onychomycosis

Placebo cure rates vary among randomized clinical trials for onychomycosis, but the factors influencing these cure rates have not been systematically investigated. The PubMed database and reference sections of relevant publications were searched for randomized controlled trials of dermatophyte toenail onychomycosis that included a placebo control and that assessed cure rates. From 21 studies, the pooled mean ± SD placebo cure rates regarding mycological, clinical, and complete cure were 8.7% ± 3.7%, 3.4% ± 2.2%, and 1.2% ± 1.4%, respectively. There was no statistically significant difference between oral and topical treatments. None of the cure rates significantly correlated with any of the participant or study design characteristics analyzed. Placebo cure rates in randomized controlled trials of toenail onychomycosis are relatively low and are independent of the study characteristics.

Oral therapy for onychomycosis: an evidence-based review

INTRODUCTION

Onychomycosis is a very common fungal infection of the nail apparatus; however, it is very hard to treat, even when the causative agent is identified, and usually requires prolonged systemic antifungal therapy. Until the 1990s, oral treatment options included only griseofulvin and ketoconazole, and the cure rate was very low. New generations of antimycotics, such as fluconazole, itraconazole and terbinafine have improved treatment success.

METHODS

Literature was identified by performing a PubMed Ovid MEDLINE, Ovid EMBASE, EBSCO CINAHL, and Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS) search. Prospective and randomized clinical trials were chosen to be included in this review. Forty-six trials were included.

RESULTS

Fluconazole, itraconazole and terbinafine are effective in the treatment of onychomycosis and have a good safety profile. When a dermatophyte is the pathogen, terbinafine produces the best results. For Candida and nondermatophyte infections, the azoles, mainly itraconazole, are the recommended therapy.

CONCLUSION

In the majority of the studies, terbinafine treatment showed a higher cure ratio than the other drugs for dermatophyte onychomycosis.

Update on terbinafine with a focus on dermatophytoses

Since terbinafine was introduced on the world market 17 years ago, it has become the leading antifungal for the treatment of superficial fungal infections, aided by unique pharmacologic and microbiologic profiles. This article reviews mode of action, antimycotic spectrum and disposition profile of terbinafine. It examines the data, accumulated over 15 years, on the comparative efficacy of terbinafine (vs griseofulvin, itraconazole, fluconazole) in the management of the infections for which it is primarily indicated (eg, dermatophytoses) and provides a brief discussion on its use for the treatment of non-dermatophyte infections. Finally, the available data on the newest topical and systemic formulations are introduced.

Recommendations for the treatment of established fungal infections

Evidence-based guidelines for the treatment of established fungal infections in the adult haematology/oncology setting were developed by a national consensus working group representing clinicians, pharmacists and microbiologists. These updated guidelines replace the previous guidelines published in the Internal Medicine Journal by Slavin et al. in 2004. The guidelines are pathogen-specific and cover the treatment of the most common fungal infections including candidiasis, aspergillosis, cryptococcosis, zygomycosis, fusariosis, scedosporiosis, and dermatophytosis. Recommendations are provided for management of refractory disease or salvage therapies, and special sites of infections such as the cerebral nervous system and the eye. Because of the widespread use newer broad-spectrum triazoles in prophylaxis and empiric therapy, these guidelines should be implemented in concert with the updated prophylaxis and empiric therapy guidelines published by this group.

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.

Pharmacotherapy of onychomycosis

Fungal infections of the nails are frequent in some segments of the population. Dermatophytes, yeasts and moulds are potential pathogens. A series of antifungal treatments are available to the clinician, differing by both their mechanistic nature and mode of administration. The pharmacodynamic and pharmacokinetic properties of each antifungal agent are distinct. This review focuses on the characteristics of amorolfine, bifonazole, ciclopirox, fluconazole, griseofulvin, itraconazole, ketoconazole, ravuconazole, R126638 and terbinafine. Single drug treatments and combined therapies are presented. None of the current drug regimens have demonstrated reliable efficacy against all cases of onychomycosis. Treatment failures, relapses and reinfections remain stubborn problems in the management of onychomycosis.

Terbinafine in the treatment of onychomycosis: a review of its efficacy in high-risk populations and in patients with nondermatophyte infections

BACKGROUND

The prevalence of onychomycosis is higher in certain high-risk populations, such as the immunocompromised, diabetics and human immunodeficiency virus (HIV)-positive patients. These patients can also develop onychomycosis due to nondermatophyte fungi. Although the efficacy of terbinafine is well demonstrated in the treatment of conventional dermatophyte nail infection, there are few data on the efficacy of terbinafine in high-risk patient groups or in nondermatophyte fungi, which can be difficult to treat.

OBJECTIVES

To review previously published data regarding the safety and efficacy of terbinafine in special patient populations, such as those with diabetes mellitus or HIV infection, those receiving immunosuppressive therapy, and patients with onychomycosis due to nondermatophyte fungi.

METHODS

A Medline literature search up to October 2002 was performed in order to identify relevant studies. Pertinent abstracts presented at international meetings were also included. Cure rates (per-protocol and intention-to-treat) were extracted or calculated. All available safety data were also collated.

RESULTS

Terbinafine was highly effective and well tolerated in patients with diabetes mellitus. Mycological cure rates of 62-78% were achieved in three studies, which is comparable with the efficacy in nondiabetic populations. Mycological cure rates of 64-91% were achieved in subsets of diabetic patients with Candida-positive nail cultures. The efficacy of terbinafine in patients receiving immunosuppressive therapy was also similar to that reported in immunocompetent patients. Levels of ciclosporin in the blood clearly decreased, with little clinical consequence; however, consideration should be given to the monitoring of ciclosporin levels in patients concomitantly receiving immunosuppressive therapy and terbinafine. Two small studies reported that terbinafine was also effective in treating onychomycosis in HIV-positive patients. Terbinafine was also effective and well tolerated in the treatment of nondermatophyte onychomycosis.

CONCLUSIONS

This review suggests that terbinafine is a safe and effective treatment for onychomycosis in high-risk populations. However, the majority of these studies only included small numbers of patients and larger clinical trials are needed, especially in patients with HIV infection.

Cumulative meta-analysis of systemic antifungal agents for the treatment of onychomycosis

BACKGROUND

Onychomycosis is a common nail disease that is often chronic, difficult to eradicate, and has a tendency to recur. The most common oral therapies for dermatophyte toenail onychomycosis include terbinafine, itraconazole and fluconazole.

OBJECTIVES

A cumulative meta-analysis of the randomized controlled trials (RCTs) for antimycotic agents was performed to determine whether the pooled estimate of the cure rates has remained consistent over the years. Furthermore, for each agent we compared the overall meta-analytical average of both mycological and clinical response rates of RCTs vs. open studies.

METHODS

We searched MEDLINE (1966 to November 2002) for relevant studies evaluating the efficacy of the oral antifungal agents terbinafine, itraconazole (pulse or continuous), fluconazole and griseofulvin for treating dermatophyte toenail onychomycosis. Studies included in this meta-analysis required a standard accepted dosage regimen, treatment duration and follow-up period. To determine the cumulative meta-analytical average, studies were sequentially pooled by adding one study at a time according to the date of publication (i.e. earliest to the most recent).

RESULTS

There were 36 studies included in the analyses. For RCTs the change in efficacy of mycological cure rates from the first trial to the overall cumulative meta-average for each drug comparator is as follows (with 95% confidence interval): terbinafine, 78 +/- 6% (n = 2 studies, 79 patients) to 76 +/- 3% (n = 18 studies, 993 patients) (P = 0.68); itraconazole pulse, 75 +/- 10% (n = 1 study, 20 patients) to 63 +/- 7% (n = 6 studies, 318 patients) (P = 0.25); itraconazole continuous, 63 +/- 5% (n = 1 study, 84 patients) to 59 +/- 5% (n = 7 studies, 1131 patients) (P = 0.47); fluconazole, 53 +/- 6% (n = 1 study, 72 patients) to 48 +/- 5% (n = 3 studies, 131 patients) (P = 0.50); and griseofulvin, 55 +/- 8% (n = 2 studies, 109 patients) to 60 +/- 6% (n = 3 studies, 167 patients) (P = 0.41). The cumulative meta-analytical average of mycological cure rates when comparing RCTs vs. open studies was: terbinafine, 76 +/- 3% (n = 18 studies, 993 patients) vs. 83 +/- 12% (n = 2 studies, 391 patients) (P = 0.0028); itraconazole pulse, 63 +/- 7% (n = 6 studies, 318 patients) vs. 84 +/- 9% (n = 3 studies, 194 patients) (P = 0.0001); and fluconazole, 48 +/- 5% (n = 3 studies, 131 patients) vs. 79 +/- 3% (n = 3 studies, 208 patients) (P = 0.0001).

CONCLUSIONS

The cumulative meta-analysis of cure rates for RCTs suggests that over time, as new RCTs have been conducted, the efficacy rates have remained consistent. The efficacy rates of open studies are substantially higher compared with RCTs and may therefore overestimate cure rates.

Terbinafine is more effective than itraconazole in treating toenail onychomycosis: results from a meta-analysis of randomized controlled trials

BACKGROUND

Toenail onychomycosis is a challenge for clinicians to treat, and this challenge is compounded by conflicting information in the medical literature concerning the efficacy of the two principal agents used in its treatment: terbinafine and itraconazole.

OBJECTIVE

The purpose of this meta-analysis is to compare the efficacy of terbinafinewith that of itraconazole in the treatment of toenail onychomycosis caused by dermatophytes.

METHODS

A Medline search was performed for all English language publications from 1966 to June 1999 on the use of terbinafine and itraconazole in the treatment of toenail onychomycosis. Included were randomized studies in which subjects received no less than 3 months (or cycles) and no more than 4 months (or cycles) of either terbinafine or itraconazole. Data were abstracted and statistical analyses (random effects model, fixed effects model, and Peto's method) were applied.

RESULTS

Thirteen studies were included from the original literature review of 1636 total referenced reports; four studies did not fulfill our inclusion or exclusion criteria. The primary analysis of six studies directly comparing terbinafine to itraconazole resulted in an odds ratio ranging from 1.8 (95% CI = 1.8, 2.8) to 2.9 (1.9, 4.1). The secondary analysis of three studies comparing either itraconazole or terbinafine to placebo estimated an odds ratio of 1.1-1.7. The former shows that terbinafine is 80%-190% more likely to result in mycologic cure than is itraconazole; the latter demonstrates a 10%-70% greater likelihood. The difference between the relative efficacies of terbinafine and itraconazole was highly statistically significant (p < 0.0001).

CONCLUSION

Meta-analysis of the published worldwide literature finds that terbinafine is significantly more effective than itraconazole at achieving mycologic cure of toenail onychomycosis.

Onychomycosis: quality of studies

OBJECTIVE

The quality of original clinical trial publications pertaining to the use of oral antifungal agents to treat onychomycosis was evaluated using predetermined criteria.

METHODS

The list of studies included in this analysis was determined by conducting a search in Medline. For each clinical trial, two independent reviewers each determined a composite score by evaluating a list of criteria that were felt to represent a good study, for example, randomization and blinding, prior sample size calculated, and treatment regimen clearly explained. A citation count was performed to determine whether higher-quality papers were cited more often than lower-quality papers.

RESULTS

Forty-five studies were included in this quality analysis of study design. Of these, 27 were considered to be "high quality" (score greater than or equal to 11 out of 20). A significant correlation coefficient of 0.997 was found between the two reviewers (P < 0.00001). Higher-quality papers were cited significantly more often than lower-quality papers (P = 0.03).

CONCLUSION

The scale that we use to evaluate the quality of onychomycosis studies has high interrater reliability. According to this scale, many published studies (18 out of 45) pertaining to treatments for onychomycosis do not meet the criteria required to be considered "high quality."

Terbinafine: a review of its use in onychomycosis in adults

Terbinafine, an orally and topically active antimycotic agent, inhibits the biosynthesis of the principal sterol in fungi, ergosterol, at the level of squalene epoxidase. Squalene epoxidase inhibition results in ergosterol-depleted fungal cell membranes (fungistatic effect) and the toxic accumulation of intracellular squalene (fungicidal effect). Terbinafine has demonstrated excellent fungicidal activity against the dermatophytes and variable activity against yeasts and non-dermatophyte molds in vitro. Following oral administration, terbinafine is rapidly absorbed and widely distributed to body tissues including the poorly perfused nail matrix. Nail terbinafine concentrations are detected within 1 week after starting therapy and persist for at least 30 weeks after the completion of treatment. Randomized, double-blind trials showed oral terbinafine 250 mg/day for 12 or 16 weeks was more efficacious than itraconazole, fluconazole and griseofulvin in dermatophyte onychomycosis of the toenails. In particular, at 72 weeks' follow-up, the multicenter, multinational, L.I.ON. (Lamisil vs Itraconazole in ONychomycosis) study found that mycologic cure rates (76 vs 38% of patients after 12 weeks' treatment; 81 vs 49% of recipients after 16 weeks' therapy) and complete cure rates were approximately twice as high after terbinafine treatment than after itraconazole (3 or 4 cycles of 400 mg/day for 1 week repeated every 4 weeks) in patients with toenail mycosis. Furthermore, the L.I.ON. Icelandic Extension study demonstrated that terbinafine was more clinically effective than intermittent itraconazole to a statistically significant extent at 5-year follow-up. Terbinafine produced a superior complete cure rate (35 vs 14%), mycologic cure rate (46 vs 13%) and clinical cure rate (42 vs 18%) to that of itraconazole. The mycologic and clinical relapse rates were 23% and 21% in the terbinafine group, respectively, compared with 53% and 48% in the itraconazole group. In comparative clinical trials, oral terbinafine had a better tolerability profile than griseofulvin and a comparable profile to that of itraconazole or fluconazole. Post marketing surveillance confirmed terbinafine's good tolerability profile. Adverse events were experienced by 10.5% of terbinafine recipients, with gastrointestinal complaints being the most common. Unlike the azoles, terbinafine has a low potential for drug-drug interactions. Most pharmacoeconomic evaluations have shown that the greater clinical effectiveness of oral terbinafine in dermatophyte onychomycosis translates into a cost-effectiveness ratio superior to that of itraconazole, fluconazole and griseofulvin.

CONCLUSION

Oral terbinafine has demonstrated greater effectiveness than itraconazole, fluconazole and griseofulvin in randomized trials involving patients with onychomycosis caused by dermatophytes. The drug is generally well tolerated and has a low potential for drug interactions. Therefore, terbinafine is the treatment of choice for dermatophyte onychomycosis.

Comparison of efficacy criteria across onychomycosis trials: need for standardization

BACKGROUND

The last 10 years have seen a substantial increase in the number of studies reporting the efficacy of the various antifungal agents used to treat onychomycosis.

AIM

To examine the definitions of efficacy parameters reported in clinical studies on the treatment of onychomycosis and discuss the importance of standardized reporting.

METHODS

We searched MEDLINE (1966-2001) for studies in which oral treatments, griseofulvin, ketoconazole, terbinafine (continuous and pulse), itraconazole (continuous and pulse), and fluconazole, were used to treat dermatophyte onychomycosis.

RESULTS

Mycologic cure was predominantly defined as negative microscopy and culture. Unlike mycologic cure, clinical parameters (e.g. clinical response, clinical cure) were variably defined. Subjective terms, such as "cure" or "markedly improved," were used; although these terms appear to be explicit, what is considered to be "cured" or "markedly improved" by one evaluator may not be by another. Also, infected nails were clinically evaluated to determine the response to treatment. Studies measured the distance between the proximal nail fold and a notch in the nail plate, at the junction between the diseased and normal-appearing nail, or in some cases estimated the diseased nail plate involvement.

CONCLUSIONS

This review of the literature on systemic agents used to treat onychomycosis shows that standard and explicit definitions are required for the accurate comparison of the effectiveness of the various therapies.

Itraconazole versus terbinafine in the management of onychomycosis: an overview

Ever since the introduction of itraconazole and terbinafine in the management of onychomycosis, there has been a revival of interest in the latter. In order to comprehend the intricate emerging scenario, an endeavor has been made to form a distinct outline in the shape of an overview on several of their facets. The review, therefore, envisages forming and facilitating instant decision-making.

Terbinafine in fungal infections of the nails: a meta-analysis of randomized clinical trials

BACKGROUND

Historically, there has been a general resistance to treating onychomycosis on the basis that such treatments were protracted and of uncertain outcome. However, modern treatments act more promptly and reliably.

OBJECTIVES

To carry out a meta-analysis to evaluate the efficacy and safety of terbinafine in comparison with placebo, itraconazole and griseofulvin.

METHODS

The analysis used data from published trials, supplemented where necessary by reference to the original trial reports.

RESULTS

Three trials were included in which terbinafine was compared with placebo. From four trials comparing terbinafine with itraconazole, a statistically significant advantage in favour of terbinafine was observed for negative culture and microscopy at the end of the trials. Furthermore, both patients and physicians reported terbinafine to be better tolerated than itraconazole. From two trials comparing terbinafine with griseofulvin, a significantly higher rate of negative microscopy and culture was observed with terbinafine.

CONCLUSIONS

A significant advantage in favour of treatment with terbinafine was observed.

Pharmacokinetics of antifungal agents in onychomycoses

Onychomycosis is caused by infection by fungi, mainly dermatophytes and nondermatophyte yeasts or moulds; it affects the fingernails and, more frequently, the toenails. Dermatophytes are responsible for about 90 to 95% of fungal infections. Trichophyton rubrum is the most common dermatophyte; Candida albicans is the major nondermatophyte yeast. Although topical therapy of onchomycosis does not lead to systemic adverse effects or interactions with concomitantly taken drugs, it does not provide high cure rates and requires complete compliance from the patient. At present there are 3 oral antifungal medications that are generally used for the short term treatment of onychomycosis: itraconazole, terbinafine and fluconazole. The persistence of these active drugs in nails allows weekly administration, reduced treatment or a pulse regimen. Good clinical and mycological efficacies are obtained with itraconazole 100 to 200 mg daily, terbinafine 250mg daily for 3 months, or fluconazole 150 mg weekly for at least 6 months. Itraconazole is a synthetic triazole with a broad spectrum of action. It is well absorbed when administered orally and can be detected in nails 1 to 2 weeks after the start of therapy. The nail : plasma ratio stabilises at around 1 by week 18 of treatment. Itraconazole is still detectable in nails 27 weeks after stopping administration. Nail concentrations are higher than the minimum inhibitory concentration (MIC) for most dermatophytes and Candida species from the first month of treatment. The elimination half-life of itraconazole from nails is long, ranging from 32 to 147 days. Terbinafine is a synthetic allylamine that is effective against dermatophytes. Terbinafine is well absorbed from the gastrointestinal tract, and the time to reach effective concentrations in nail is 1 to 2 weeks. The half-life is from 24 to 156 days, explaining the observed persistence of terbinafine in nails for longer than 252 days. Fluconazole is a bis-triazole broad spectrum antifungal with high oral bioavailability. The uptake of fluconazole by nail increases with the length of treatment, and nail : plasma ratios are generally 1.5 to 2 at steady state. Fluconazole concentrations exceed the MIC for Candida species soon after the start of treatment. Fluconazole concentrations fall slowly after the drug is stopped, with a half-life of 50 to 87 days, and fluconazole is still detectable in nails 5 months after the end of treatment. All these drugs are potent inhibitors of cytochrome P450 (CYP) enzymes and may increase the plasma concentrations of concomitantly used drugs. Itraconazole inhibits CYP3A4. Fluconazole inhibits CYP3A4, but to a lesser degree than itraconazole, CYP2C9 and CYP2C19. Terbinafine inhibits CYP2D6.

Cost effectiveness of oral terbinafine (Lamisil) compared with oral fluconazole (Diflucan) in the treatment of patients with toenail onychomycosis

OBJECTIVE

To determine the cost effectiveness of terbinafine (Lamisil) tablets compared with fluconazole (Diflucan) capsules in the treatment of patients with toenail onychomycosis.

METHODS

Data from a randomised, double-blind, double-dummy, multicentre study were used as the basis for this study. Terbinafine 250 mg/day for 12 weeks (n = 48) was compared with fluconazole 150mg once weekly for 12 weeks (n = 45) or 24 weeks (n = 44) in patients with culture-confirmed toenail onychomycosis caused by dermatophyte infection. At the end of the study (week 60), complete clinical cure of the target toenail was achieved in 67% of patients in the terbinafine group, compared with 21 and 32%, respectively, in the 12- and 24-week fluconazole groups. We subsequently used these data to calculate the cost effectiveness of the three treatment regimens, defining cost effectiveness as the cost per complete clinical cure of the target toenail at week 60.

RESULTS

The cost effectiveness of terbinafine for each complete clinical cure was superior to that of either of the fluconazole regimens. Costs per cure were Finnish markka (Fmk) 2824 ($US618) for terbinafine, compared with Fmk3748 ($US820) and Fmk4922 ($US1077), respectively, for the two fluconazole regimens.

CONCLUSIONS

The clinical study showed that terbinafine was significantly more effective than fluconazole in the treatment of onychomycosis, achieving statistically higher rates of mycological and clinical cure. We have now shown that terbinafine is also more cost effective. These findings have important implications for both medical and social policy.

Pharmacoeconomic analysis of ciclopirox nail lacquer solution 8% and the new oral antifungal agents used to treat dermatophyte toe onychomycosis in the United States

BACKGROUND

Recently a novel topical nail lacquer, ciclopirox solution 8%, has been approved for the treatment of onychomycosis.

OBJECTIVE

This was undertaken to determine the most cost-effective treatment for the treatment of dermatophyte onychomycosis of the toes in the United States in 2000.

METHODS

The nature of the problem was defined. The drug comparators were ciclopirox nail lacquer, terbinafine, itraconazole (pulse), itraconazole (continuous), fluconazole, and griseofulvin. A decision analytic model that reflected the manner in which pedal tinea unguium is managed was produced. Studies that have evaluated the efficacy of the nail lacquer and the oral antifungal agents for this indication were identified. Appropriate studies were used in a meta-analysis to determine the mycologic and clinical response rates when the drug comparators are used for the treatment for toe dermatophyte onychomycosis. For each drug comparator a cost of regimen analysis was carried out. This is the sum of the drug acquisition cost, the cost of medical management, and the cost of managing adverse effects. Next, the expected cost of management was calculated, disease free days were determined, and a sensitivity analysis was conducted.

RESULTS

For each comparator the meta-analytic average mycologic cure (MC) rate and clinical response (CR) rates were: ciclopirox nail lacquer (MC: 52.6 +/- 4.2%, CR: 52.4 +/- 9.0%), griseofulvin (MC: 41.1 +/- 20.4%, CR: 33.7 +/- 14.1%), itraconazole (continuous) (MC: 66.3 +/- 4.2%, CR: 70.3 +/- 4.2%), itraconazole (pulse) (MC: 70.8 +/- 5.7%, CR: 73.6 +/- 4.6%), terbinafine (MC: 77.2 +/- 4.0%, CR: 75.3 +/- 2.9%), and fluconazole (MC: 65.6 +/- 7.1%, CR: 66.5 +/- 11.7%). The cost of regimen for the drug comparators was: ciclopirox nail lacquer $325.2, griseofulvin $1413.1, itraconazole (continuous) $1410.2, itraconazole (pulse) $811.7, terbinafine $890.1, and fluconazole $966.8. The cost/mycologic cure rate and expected cost/expected symptom free day were, ciclopirox nail lacquer ($618.2, 1.69), griseofulvin $3438.2, 5.3), itraconazole (continuous) ($2126.9, 3.52), itraconazole (pulse) ($1146.4, 2.01), terbinafine ($1153.0, 2.14), and fluconazole ($1473.7, 2.10). The relative cost-effectiveness was ciclopirox nail lacquer 1.00, itraconazole (pulse) 1.19, fluconazole 1.24, terbinafine 1.27, itraconazole (continuous) 2.08, and griseofulvin 3.13. Sensitivity analysis indicated that ciclopirox nail lacquer was a cost effective alternative compared with the oral regimens of terbinafine, itraconazole (continuous), and griseofulvin when clinical response rate was used as the primary efficacy parameter.

CONCLUSION

Ciclopirox nail lacquer solution 8% is a recent addition to the armamentarium of therapies available to the physician and patient for the treatment of onychomycosis. The nail lacquer is a cost effective agent compared with the oral antifungal therapies, terbinafine, itraconazole, fluconazole, and griseofulvin.

A double-blind, randomized study to compare the efficacy and safety of terbinafine (Lamisil) with fluconazole (Diflucan) in the treatment of onychomycosis

In a randomized, double-blind, double-placebo, multicentre study, terbinafine 250 mg daily for 12 weeks was compared with fluconazole 150 mg once weekly for 12 or 24 weeks in the treatment of onychomycosis. A total of 137 patients with culture-confirmed onychomycosis was divided into three groups: group A received terbinafine for 12 weeks, group B received fluconazole for 12 weeks, while group C received fluconazole for 24 weeks. At completion of the study (week 60), the mycological cure rate was higher in the terbinafine group than in the fluconazole groups: 89% vs. 51% and 49%, respectively (P < 0.001). The length of unaffected nail increased until week 24 in group B and until week 36 in group C, but was still increasing in group A at the final visit (week 60). Complete clinical cure of the target nail at week 60 was 67% in the terbinafine group, compared with 21% and 32% in the fluconazole groups, respectively. The incidence of adverse events was low for both study agents. We conclude that terbinafine 250 mg daily for 12 weeks is significantly more effective in the treatment of onychomycosis than fluconazole 150 mg once weekly for either 12 or 24 weeks.

A risk-benefit assessment of the newer oral antifungal agents used to treat onychomycosis

The newer antifungal agents itraconazole, terbinafine and fluconazole have become available to treat onychomycosis over the last 10 years. During this time period these agents have superseded griseofulvin as the agent of choice for onychomycosis. Unlike griseofulvin, the new agents have a broad spectrum of action that includes dermatophytes, Candida species and nondermatophyte moulds. Each of the 3 oral antifungal agents, terbinafine, itraconazole and fluconazole, is effective against dermatophytes with relatively fewer data being available for the treatment of Candida species and nondermatophyte moulds. Itraconazole is effective against Candida onychomycosis. Terbinafine may be more effective against C. parapsilosis compared with C. albicans; furthermore with Candida species a higher dose of terbinafine or a longer duration of therapy may be required compared with the regimen for dermatophytes. The least amount of experience in treating onychomycosis is with fluconazole. Griseofulvin is not effective against Candida species or the nondermatophyte moulds. The main use of griseo-fulvin currently is to treat tinea capitis. Ketoconazole may be used by some to treat tinea versicolor with the dosage regimens being short and requiring the use of only a few doses. The preferred regimens for the 3 oral antimycotic agents are as follows: itraconazole - pulse therapy with the drug being administered for 1 week with 3 weeks off treatment between successive pulses; terbinafine - continuous once daily therapy; and fluconazole - once weekly treatment. The regimen for the treatment of dermatophyte onychomycosis is: itraconazole - 200mg twice daily for I week per month x 3 pulses; terbinafine - 250 mg/day for 12 weeks; or, fluconazole - 150 mg/wk until the abnormal-appearing nail plate has grown out, typically over a period of 9 to 18 months. For the 3 oral antifungal agents the more common adverse reactions pertain to the following systems, gastrointestinal (for example, nausea, gastrointestinal distress, diarrhoea, abdominal pain), cutaneous eruption, and CNS (for example, headache and malaise). Each of the new antifungal agents is more cost-effective than griseofulvin for the treatment of onychomycosis and is associated with high compliance, in part because of the shorter duration of therapy. The newer antifungal agents are generally well tolerated with drug interactions that are usually predictable.

Long-term outcomes in the treatment of toenail onychomycosis

Most clinical studies in subjects with toenail onychomycosis end with a final assessment at 48-52 weeks. This fails to take full account of the physiology of toenail growth, as toenails can take up to 12-18 months to grow out fully. Accurate assessment of long-term outcomes therefore requires follow-up of at least 2 years after completion of the study. We have evaluated long-term outcomes of treatment in the patients whom we contributed to two multicentre studies of oral therapy for toenail onychomycosis caused by dermatophyte infection. In the first, a dose-finding study for terbinafine (Lamisil), the high rates of mycological and clinical cure achieved by terbinafine at week 48 were maintained more than 2 years after completion of the study. In the second, a comparative study between terbinafine and itraconazole (Sporanox), the excellent mycological and clinical cure rates achieved by terbinafine at week 48 were again maintained more than 2 years after completion of the study. By contrast, the failure and relapse rates seen with itraconazole were much higher. Other studies undertaken in recent years have confirmed these positive findings with respect to terbinafine, and have demonstrated its superiority over itraconazole in maintaining mycological and clinical cure over long periods. These long-term benefits of terbinafine probably relate to its primarily fungicidal action against dermatophytes, compared to the fungistatic action of itraconazole and other triazole agents. Future clinical studies should therefore incorporate at least 2 years' follow-up.

Randomized double-blind comparison of short-term itraconazole and terbinafine therapy for toenail onychomycosis

Previous studies evaluating short-term itraconazole and terbinafine therapy for onychomycosis have varied in protocol and size; this double-blind study enabled a large-scale, standardized, direct comparison. Patients with toenail onychomycosis were randomized to itraconazole 200 mg daily (n = 146) or terbinafine 250 mg daily (n = 146) for 12 weeks, with a 36-week follow-up. Mycological cure rates at the follow-up end-point were significantly equivalent (61% with itraconazole vs. 67% with terbinafine). A similar proportion of patients in each group experienced adverse events during treatment (itraconazole, 22%; terbinafine, 23%). More patients receiving terbinafine stopped treatment permanently because of treatment-related adverse events (8% vs. 1%).

Pediatric antifungal therapy

The most common superficial dermatophyte infections in children involve the scalp, skin, and nails. Griseofulvin has traditionally served as the standard of care for scalp and nail infections, but an increasing proportion of tinea capitis infections are proving refractory or very slowly responsive to treatment. This article will review new antifungal therapies available and their future role in the treatment of pediatric dermatophyte infections. As these new agents are not yet FDA approved for use in the pediatric dermatophyte infections, the practitioner must be aware of possible risks and benefits of such drugs, and counsel families appropriately regarding "off-label" use.

Long-term follow up of patients with toenail onychomycosis after treatment with terbinafine

The long-term outcome of 111 patients treated with oral terbinafine for toenail onychomycosis with a novel treatment protocol was assessed a median of 138 weeks after entry into the trial. All but three patients had either one or two 12 week courses of terbinafine 250 mg daily. Of the 77 evaluable patients, 72.7% were still classified as responders (i.e. negative mycological culture and at least 3 mm of new unaffected nail growth) on reassessment. The present study shows that a favourable long-term outcome can be achieved in patients who have been treated with at least one 12 week course of terbinafine.

Current issues in onychomycosis

OBJECTIVE

To review the epidemiology, mycology, clinical features and diagnosis, current pharmacotherapy, and pharmacoeconomics of onychomycosis.

DATA SOURCES

We conducted a MEDLINE search from 1966 to May 1997. References from these articles, manufacturers of the discussed antimycotics, and relevant abstracts from recent dermatology conferences were used to collect pertinent data.

DATA EXTRACTION

Data were obtained from published controlled studies and case reports. In the pharmacotherapy section, the most weight was placed on fully reported, randomized, controlled comparative trials, but abstracts and case series were included when well-controlled studies were unavailable.

DATA SYNTHESIS

Onychomycosis is a common nail disorder that has a substantial impact on patients' quality of life. It is most commonly caused by dermatophytes, but yeasts and molds can also be involved. Diagnosis is made through clinical presentation, potassium hydroxide preparations, and culture of tissue/nail samples. Griseofulvin was the drug of choice for many years, but its low cure rates and the development of newer, more effective drugs made it fall out of favor. Current therapeutic alternatives include fluconazole, itraconazole, and terbinafine. Data on the use of fluconazole are limited to case series and reports. Continuous dosing of itraconazole and terbinafine are well-proven therapies. New data are becoming available on the use of pulse itraconazole dosing, which has recently been approved by the Food and Drug Administration for fingernail infections. These drugs are well tolerated, but attention to drug interactions is necessary with the azoles.

CONCLUSIONS

Currently, continuous terbinafine appears to be the most cost-effective drug for dermatophyte onychomycosis.

Long-term post-treatment follow-up of onychomycosis treated with terbinafine: a multicentre trial

Between 1991 and 1993, 32 cases of fingernail mycosis and 20 cases of toenail mycosis caused by dermatophytes were treated with terbinafine. For 8 weeks, 250 mg of terbinafine was given daily for fingernail infections, and for 12 weeks the same dose was given for toenail involvement; the short-term follow-up was 24 and 48 weeks respectively. A long-term follow-up was performed twice, initially at 24 and then at 48 months after the end of the treatment. For fingernail mycosis, the mycological cure rate was 100% at the end of month 24 and 91% at the end of month 48. Mycological cultures gave negative results in toenail infections in 90% after 24 months and in 86% after 48 months. After 24 months, 23 out of 26 patients (88%) with fingernail and 17 out of 20 patients (95%) with toenail mycosis were clinically cured. After 48 months, 20 out of 22 cases (91%) with fingernail and 10 out of 14 cases (71%) with toenail involvement showed a complete cure.

Terbinafine: an update

Oral terbinafine was first introduced in the United Kingdom in February 1991 and was approved for the treatment of onychomycosis in the United States in May 1996. It is estimated that 4 million patients worldwide have been treated with oral terbinafine as of December 1996. The efficacy of terbinafine in the treatment of onychomycosis and other dermatomycoses is reviewed. The adverse-effects profile of oral terbinafine is evaluated.

Oral terbinafine: a new antifungal agent

OBJECTIVE

To review the pharmacology, pharmacokinetics, efficacy, adverse effects, drug interactions, and dosage guidelines of terbinafine. Available comparative data of terbinafine and other antimycotic agents are described for understanding the potential role of terbinafine in patient care.

DATA SOURCES

A MEDLINE search restricted to English language during 1966-1996 and extensive review of journals was conducted to prepare this article. MeSH headings included allylamines, terbinafine, SF 86-327, dermatophytosis, dermatomycosis.

DATA EXTRACTION

The data on pharmacokinetics, adverse effects, and drug interactions were obtained from open-label and controlled studies and case reports. Controlled single- or double-blind studies were evaluated to describe the efficacy of terbinafine in the treatment of various fungal infections.

DATA SYNTHESIS

Terbinafine is the first oral antimycotic in the allylamines class: a fungicidal agent that inhibits ergosterol synthesis at the stage of squalene epoxidation. Terbinafine demonstrates excellent in vitro activity against the majority of dermatophyte species including Trichophyton rubrum, Trichophyton mentagrophytes, and Epidermophyton floccosum; less activity is seen against Dematiaceae and the filamentous fungi. It is least active against the pathogenic yeast and this correlates with the relatively poor efficacy against these organisms in vivo. High concentrations of terbinafine are achieved in keratinous tissues, the site of superficial infections, and these concentrations are maintained for up to 3 months. The clinical efficacy of terbinafine against a number of dermatophyte infections exceeds that of the current standard of therapy, griseofulvin. The efficacy of terbinafine may be as good or better than that of the azole antifungals. Additional studies are required to confirm these observations. Terbinafine demonstrates a good safety profile, and relatively few drug interactions have been identified.

CONCLUSIONS

Terbinafine is more effective than the gold standard, griseofulvin, in the treatment of tinea pedis and tinea unguinum, with considerably shorter treatment duration in the latter. It has been proven as effective as griseofulvin in the treatment of tinea capitis, tinea corporis, and tinea cruris. Terbinafine does not appear to offer any advantage in the treatment of nondermatophyte infections; its utility in the treatment of systemic infections has yet to be established. Depending on individual institutional costs, terbinafine may be a front-line drug for some superficial infections responding poorly to the current standard of therapy.