Fluconazole in the treatment of onychomycosis caused by dermatophytes

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.

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.

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.

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."

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.

An open, randomized, comparative study of oral fluconazole, itraconazole and terbinafine therapy in onychomycosis

BACKGROUND/AIM

In this open, randomized and comparative study, the safety and efficacy of systemic fluconazole, itraconazole and terbinafine was investigated in 50 patients with distal subungual toenail onychomycosis diagnosed clinically and mycologically. The patients with positive mycology and also the patients with positive microscopy and negative culture were investigated.

METHODS

The treatment duration was 3 months, and the follow-up period was 6 months. Patients were randomly assigned: 16 patients received 150 mg fluconazole once weekly, 18 patients received 200 mg itraconazole twice daily with meals during the first week of each month, and 16 patients received 250 mg/day terbinafine during the treatment period.

RESULTS

In a clinical evaluation, at the endpoint of the follow-up period, the clinical cure rates were 81.3% (13/16) in the terbinafine group, 77.8% (14/18) in the itraconazole group, and 37.5% (6/16) in the fluconazole group. The mycological cure rates were 75% (12/16), 61.1% (11/18) and 31.2% (5/16), respectively. The overall assessment rates were 62.5% (10/16), 61.1% (11/18) and 31.2% (5/16), respectively. Statistically significant intra-group reductions from baseline symptom severity values were seen at the endpoint of treatment and at the endpoint of the follow-up period for all three treatment groups in onycholysis, subungual hyperkeratosis, affected-area percentage score and total score parameters (p < 0.001). At the endpoint of the follow-up period, statistically significant differences between the treatment groups were seen in clinical, mycological and overall assessment (p < 0.05). However, while no statistically significant difference between the terbinafine and itraconazole groups was seen, there was a clinical and statistical difference between the other groups and the fluconazole group. Treatment was not stopped for side effects such as mild gastrointestinal and central nervous system symptoms. These effects were noted in four patients in the fluconazole group (25%), five patients in the itraconazole group (27.8%), and three patients in the terbinafine group (18.75%). The clinical laboratory data on all three drug groups did not show any statistically or clinically significant intra-group changes from baseline values at the endpoint (p > 0.05).

CONCLUSION

This comparative study of systemic fluconazole, itraconazole and terbinafine showed that all three drugs were effective and safe in the treatment of onychomycosis. However, fluconazole, at these doses and treatment durations, was the least effective. With regard to cost-effectiveness, side effects and the cure rates, terbinafine could be the drug of choice in the short-term treatment of toenail onychomycosis.

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.

Onychomycosis: a compendium of facts and a clinical experience

Fifty percent of all nail disturbances result from onychomycosis, with toenails being affected approximately four times as often as those of the fingernails. The overall incidence in the population is not known, but it is reported at about 2%-13% and is presently on the rise. This lengthy paper reviews all facets of onychomycosis. The present-day classification of onychomycosis is presented. Predisposing factors, causative organisms, as well as the differential diagnosis are included. A thorough comparison of the five presently available oral antifungal agents (griseofulvin, ketoconazole, itraconazole, terbinafine, and fluconazole) in an easy-to-read table is presented. A second table presents many studies performed by many researchers in various countries on these same drugs. The author has included her own personal clinical experience using both fluconazole and terbinafine in 22 and 51 patients with pedal onychomycosis, respectively. This is not meant to be a "controlled study," but rather the experience of one podiatrist in an office setting. The newer oral antifungal agents (itraconazole, terbinafine, and fluconazole) are highly recommended even for the most severe cases of onychomycosis.

Pharmacokinetics of fluconazole in skin and nails

Two studies on the pharmacokinetics of fluconazole in skin and nails are reported here. In 1 study, 12 healthy volunteers received fluconazole 50 mg once daily for 12 days and 11 healthy volunteers received fluconazole 150 mg once weekly for 2 weeks. Fluconazole assays were performed on samples of serum, stratum corneum, dermis-epidermis, and eccrine sweat. In a second study, 36 patients with toenail onychomycosis received either fluconazole 150 mg once weekly or griseofulvin 1000 mg once daily for 12 months. Fluconazole assays were performed on nail clippings and serum samples from the patients receiving fluconazole. Tissue concentrations of fluconazole regularly exceeded plasma concentrations in these studies. In the skin study, the highest concentrations were achieved in stratum corneum, with accumulation occurring up to the end of dosing. Subjects who received 50 mg once daily had higher levels of fluconazole in stratum corneum, sweat, and epidermis-dermis than those subjects who received 150 mg once weekly. In the toenail study, fluconazole concentrations increased for the first 6 months, reaching levels much higher than serum concentrations (P < .001), with no significant difference between healthy and diseased nails.

Current topics in diagnosis and treatment of tinea unguium in Japan

The number of patients with tinea unguium accounts for 0.5% to 2% of the total number of outpatients in Japan. The diagnosis of tinea unguium can be relatively easily made on the basis of clinical symptoms and direct microscopic findings. However onychomycosis due to fungi other than dermatophytes should always be suspected if no dermatophytes are cultured despite positive findings in direct microscopy. In such cases, it is necessary to repeat cultures and conduct histopathological evaluation using PAS-staining technique or enzyme antibody technique. At present, oral administration of griseofulvin and terbinafine are the treatments covered by health insurance in Japan. In the future, however, other orally active antifungal drugs such as itraconazole and fluconazole will become available for use by in-patients who do not respond to griseofulvin. It is essential to patiently continue treatment even if oral therapy is impossible, because other therapies such as ODT therapy using topical antifugal agents and urea ointment or abrading affected nails as much as possible with a file or dental drill may be effective without oral therapy.

Current and emerging azole antifungal agents

Major developments in research into the azole class of antifungal agents during the 1990s have provided expanded options for the treatment of many opportunistic and endemic fungal infections. Fluconazole and itraconazole have proved to be safer than both amphotericin B and ketoconazole. Despite these advances, serious fungal infections remain difficult to treat, and resistance to the available drugs is emerging. This review describes present and future uses of the currently available azole antifungal agents in the treatment of systemic and superficial fungal infections and provides a brief overview of the current status of in vitro susceptibility testing and the growing problem of clinical resistance to the azoles. Use of the currently available azoles in combination with other antifungal agents with different mechanisms of action is likely to provide enhanced efficacy. Detailed information on some of the second-generation triazoles being developed to provide extended coverage of opportunistic, endemic, and emerging fungal pathogens, as well as those in which resistance to older agents is becoming problematic, is provided.

Onychomycosis: pathogenesis, diagnosis, and management

Although not life-threatening, onychomycosis (a fungal infection of the nail, usually caused by a dermatophyte) constitutes an important public health problem because of its high prevalence (about 10% of the U.S. population) and associated morbidity. The disease can have certain negative consequences for patients, such as pain, and can potentially undermine work and social lives. This review discusses the etiology, classification, diagnosis, and treatment of onychomycosis. Four types of onychomycosis are recognized based on the site and pattern of fungal invasion. Dermatophyte fungi are the predominant pathogens, but yeasts (especially Candida albicans) and nondermatophyte molds may also be implicated. Accurate diagnosis requires direct microscopy and fungal culture. The differential diagnosis includes psoriasis, lichen planus, onychogryphosis, and nail trauma. Onychomycosis is more difficult to treat than most dermatophytoses because of the inherent slow growth of the nail. Older antifungal agents (ketoconazole and griseofulvin) are unsuitable for onychomycosis because of their relatively poor efficacy and potential adverse effects. Three recently developed antimycotic agents (fluconazole, itraconazole, and terbinafine) offer high cure rates and good safety profiles. In addition, the short treatment times (< 3 months) and intermittent dosing schedules are likely to enhance compliance and reduce the costs of therapy.

Once-weekly fluconazole (150, 300, or 450 mg) in the treatment of distal subungual onychomycosis of the toenail

BACKGROUND

Onychomycosis is a prevalent infection of the nail caused primarily by dermatophytes. Fluconazole is active in vitro against the most common pathogens of onychomycosis, penetrates into the nail bed, and is clinically effective in the treatment of a wide variety of superficial fungal infections.

OBJECTIVE

The purpose of this study was to compare the efficacy and safety of three different doses of fluconazole (150, 300, and 450 mg) given orally once weekly to that of placebo in the treatment of distal subungual onychomycosis of the toenail caused by dermatophytes.

METHODS

In this multicenter, double-blind study, 362 patients with mycologically confirmed onychomycosis were randomized to treatment with fluconazole, 150, 300, or 450 mg once weekly, or placebo once weekly for a maximum of 12 months. To enter the study, patients were required to have at least 25% involvement of the target nail with at least 2 mm of healthy nail from the nail fold to the proximal onychomycotic border. Patients who were clinically cured or improved at the end of treatment were further evaluated over a 6 month follow-up period. At both the end of therapy and the end of follow-up, clinical success of the target nail was defined as reduction of the affected area to less than 25% or cure.

RESULTS

At the end of therapy, 86% to 89% of patients in the fluconazole treatment groups were judged clinical successes as defined above compared with 8% of placebo-treated patients. Clinical cure (completely healthy nail) was achieved in 28% to 36% of fluconazole-treated patients compared with 3% of placebo-treated patients. Fluconazole demonstrated mycologic eradication rates of 47% to 62% at the end of therapy compared with 14% for placebo. The rates at the end of follow-up were very similar, indicating that eradication of the dermatophyte was maintained over the 6-month period. All efficacy measures for the fluconazole groups were significantly superior to placebo (p=0.0001); there were no significant differences between the fluconazole groups on these efficacy measures. The clinical relapse rate among cured patients over 6 months of follow-up was low at 4%. Fluconazole was well tolerated at all doses over the 12-month treatment period, with the incidence and severity of adverse events being similar between the fluconazole and placebo treatment groups. Mean time to clinical success in the fluconazole treatment groups was 6 to 7 months. This time frame may be used as a guideline for fluconazole treatment duration.

CONCLUSION

The results of this study support the use of fluconazole in the treatment of distal subungual onychomycosis of the toenail caused by dermatophytes. Doses between 150 to 450 mg weekly for 6 months were clinically and mycologically effective as well as safe and well tolerated.

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.

Accumulation of fluconazole in scalp hair

The accumulation in scalp hair of the antimycotic triazole, fluconazole, was studied during and after administration. Fluconazole 50 mg was administered to 12 healthy subjects as a single capsule each day for 28 days. The concentration of fluconazole 5 hours after administration was measured in different 1-cm sections of scalp hair at intervals during treatment and for 6 months after the end of treatment. In each section of scalp hair the concentration of fluconazole increased during treatment and was consistently higher than values found in plasma. For example, the mean concentration in the first hair section on day 28, 19.8 micrograms/g, corresponded to a mean penetration ratio relative to plasma of 9.42. During administration, the maximal concentration of fluconazole was found in the first hair section. After cessation of administration, the measured concentrations of fluconazole decreased and greater concentrations were found in the distal hair sections, presumably as a result of hair growth. Fluconazole was detectable, however, in the hair of 9 of the 12 subjects even 6 months after treatment. The mean concentration of fluconazole in hair bulbs on day 28 was 12.1 micrograms/g (n = 6), corresponding to a mean penetration ratio of 5.99. In a second study, fluconazole was administered as a single oral 150-mg capsule per week for 4 weeks to a group of 8 healthy subjects. The mean fluconazole concentration in whole scalp hair 5 hours after the last dose was 3.2 micrograms/g.

Superficial fungal infections. Errors to avoid in diagnosis and treatment

Superficial fungal infections are easily managed once the proper diagnosis is made. However, misdiagnosis is not uncommon, and many standard approaches to treatment popular just a few years ago are now out of date or in need of refinement. Through nine illustrative cases, the authors describe pitfalls in diagnosis and treatment of common fungal infections involving the skin, hair, and nails.

Current management of onychomycosis. An overview

Until recently pedal onychomycosis, particularly when it affected several nails or involved a large nail plate area, was often regarded as untreatable. The advent of new therapies such as itraconazole, terbinafine, and fluconazole has been a significant and welcome addition to the armamentarium of therapies at the disposal of the physician. These drugs appear in the nail plate within days of starting oral therapy, being taken up by both the nail matrix and the nail bed. The duration required for effective therapy has been reduced, while the efficacy rates and cost-effectiveness have increased compared with the older treatments, such as griseofulvin. Some of the newer agents appear to have a wider spectrum of activity. Thus far, the newer agent have exhibited a low risk to benefit ratio. I may be possible to combine oral therapies with topical and surgical treatments, thereby further increasing efficacy rates and the cost-effectiveness while decreasing adverse effects and duration of oral therapy.

New therapies for onychomycosis

Until recently, the treatment of onychomycosis was discouraging because of the relatively low success rate, the need for prolonged therapy, and the laboratory monitoring necessary with the traditional oral antifungal agents, griseofulvin and ketoconazole. The advent of a new generation of oral antifungal drugs, including two triazoles (itraconazole and fluconazole) and an allylamine (terbinafine), has greatly improved the outlook for patients with fungal nail infections, particularly those with toenail involvement. Recently, the broad-spectrum triazole, itraconazole, has been approved for the treatment of onychomycosis in the U.S. Numerous studies have demonstrated its efficacy when administered either continuously for 3 months or in "pulse" dosing. Preliminary findings suggest that fluconazole and terbinafine are also promising, although their spectrum of activity is not as broad as that of itraconazole.

Intermittent fluconazole dosing in patients with onychomycosis: results of a pilot study

BACKGROUND

Therapeutic limitations of griseofulvin in treating onychomycosis have led to a search for alternative antimycotic agents. An optimal dosing regimen for fluconazole has yet to be defined.

OBJECTIVE

Our purpose was to evaluate the intermittent use of fluconazole (either once-weekly or alternate-day dosing) without concurrent nail avulsion in patients with moderate to severe onychomycosis.

METHODS

Eleven patients with mycologically confirmed onychomycosis of the toenails or fingernails (43 infected nails) were treated with intermittent fluconazole until clinical cure was obtained. Eight patients received fluconazole 300 mg once weekly, one patient received 200 mg once weekly, and two patients received 100 or 200 mg of fluconazole every other day. Eight patients also used an adjunctive topical antimycotic preparation.

RESULTS

All six patients with toenails involved (32 infected nails) were clinically cured after a mean treatment duration of 6 months, and all five patients with fingernails involved (11 infected nails) were cured after 3.7 months. There were no significant clinical or laboratory adverse events.

CONCLUSION

Intermittent fluconazole, taken once weekly or on alternate days, is a well-tolerated and efficacious method to treat onychomycosis.

Oral therapeutic agents in fungal nail disease

Oral griseofulvin has been the first-line drug in the therapy of dermatophyte onychomycosis for many years. Even when used long-term, it is effective in only about 30% of patients. Ketoconazole is not much more effective than griseofulvin in toenail infections, and there are significant problems with hepatotoxicity. Recently the triazoles, itraconazole and fluconazole, and the allylamine, terbinafine, were introduced and are believed to be potentially suitable for the oral treatment of fungal nail infection. Terbinafine is particularly effective in the treatment of dermatophyte onychomycosis, with a much shorter treatment period than griseofulvin. Cure rates of well over 80% have been noted in fingernail and toenail infection during treatment periods of 6 and 12 weeks, respectively. Itraconazole, 200 mg/day, has been noted in some studies to be similarly effective in the same treatment period. Few studies of fluconazole in nail infection have been carried out. These new agents appear to be safe, and results thus far suggest that they will soon overtake griseofulvin as the drug of choice in the oral therapy of nail infection.

Antifungal agents: an overview. Part II

The recent introduction of a new generation of antifungal drugs promises to alter significantly therapy for both systemic and superficial mycoses, in particular, onychomycosis. This article presents an in-depth review of the azoles (the triazoles itraconazole and fluconazole), the allylamines (naftifine and terbinafine), and the morpholine derivative amorolfine.

Dermatologic therapy: 1992

This article reviews therapeutic studies reported in the English-language literature during 1992. Readers should review the original article in full before attempting any experimental or controversial therapy.