Onychomycosis. Treatment, quality of life, and economic issues

Efinaconazole topical solution, 10%: the development of a new topical treatment for toenail onychomycosis

BACKGROUND

Toenail onychomycosis is a common disease with limited treatment options; treatment failure and relapse are frequently encountered. Many patients experience long-standing disease affecting multiple toenails, with substantial discomfort and pain. Although some patients might prefer a topical therapy, efficacy with ciclopirox nail lacquer has been disappointing.

METHODS

Efinaconazole topical solution, 10% is the first topical triazole antifungal agent specifically developed for the treatment of onychomycosis. This paper reviews the preclinical and clinical data on efinaconazole topical solution, 10%.

RESULTS

Efinaconazole has a broad spectrum of antifungal activity in vitro and is more potent than ciclopirox against common onychomycosis pathogens. It has a more optimal keratin affinity than ciclopirox, and it exhibits significantly greater in vivo activity owing to its superior nail penetration. Mycologic cure rates at week 52 were 55.2% (study 1) and 53.4% (study 2) with efinaconazole topical solution, 10% compared with 16.8% and 16.9%, respectively, with vehicle (P<.001 for both). In addition, efinaconazole is well tolerated.

CONCLUSIONS

Efinaconazole topical solution, 10% may likely become a preferred topical agent for the management of mild-to-moderate onychomycosis.

Nucleotide sequence analysis of beta tubulin gene in a wide range of dermatophytes

We investigated the resolving power of the beta tubulin protein-coding gene (BT2) for systematic study of dermatophyte fungi. Initially, 144 standard and clinical strains belonging to 26 species in the genera Trichophyton, Microsporum, and Epidermophyton were identified by internal transcribe spacer (ITS) sequencing. Subsequently, BT2 was partially amplified in all strains, and sequence analysis performed after construction of a BT2 database that showed length ranged from approximately 723 (T. ajelloi) to 808 nucleotides (M. persicolor) in different species. Intraspecific sequence variation was found in some species, but T. tonsurans, T. equinum, T. concentricum, T. verrucosum, T. rubrum, T. violaceum, T. eriotrephon, E. floccosum, M. canis, M. ferrugineum, and M. audouinii were invariant. The sequences were found to be relatively conserved among different strains of the same species. The species with the closest resemblance were Arthroderma benhamiae and T. concentricum and T. tonsurans and T. equinum with 100% and 99.8% identity, respectively; the most distant species were M. persicolor and M. amazonicum. The dendrogram obtained from BT2 topology was almost compatible with the species concept based on ITS sequencing, and similar clades and species were distinguished in the BT2 tree. Here, beta tubulin was characterized in a wide range of dermatophytes in order to assess intra- and interspecies variation and resolution and was found to be a taxonomically valuable gene.

Tavaborole for the treatment of onychomycosis

INTRODUCTION

Onychomycosis causes approximately one-half of all nail disorders and its prevalence has been steadily increasing. It is difficult to treat, partly due to the subungual location and the inability of both oral and topical antifungals to reach the site of infection. Published cure rates with oral drugs are < 50% and even lower with topical drugs. Pathogenic factors include the diversity of fungal organisms and the difficulty of drugs penetrating the nail plate. Tavaborole is a broad-spectrum oxaborole antifungal agent with low molecular weight, permitting optimal nail plate penetration. In vitro and ex vivo studies have demonstrated the superior nail-penetrating properties of tavaborole compared to existing topical antifungal medications approved for the treatment of onychomycosis.

AREAS COVERED

The clinical characteristics and prevalence of onychomycosis, currently available treatments, and the chemistry, safety and pharmacokinetic properties of tavaborole for the treatment of onychomycosis.

EXPERT OPINION

Tavaborole is a novel, topical antifungal pharmaceutical agent pending FDA approval for the treatment of toenail onychomycosis due to dermatophytes. Efficacy has been demonstrated by a clinical development program including in vitro data and two large Phase III trials that enrolled ∼ 1200 patients. When approved, tavaborole topical solution, 5% may become a safe and effective option for the treatment of onychomycosis.

The unique chemistry of benzoxaboroles: current and emerging applications in biotechnology and therapeutic treatments

Benzoxaboroles have garnered much attention in recent years due to their diverse applications in bio-sensing technology, material science, and therapeutic intervention. Part of the reason arises from the benzoxaboroles' unique chemical properties, especially in comparison to their acyclic boronic acid counterparts. Furthermore, the low bio-toxicity combined with the high target specificity associated with benzoxaboroles make them very attractive as therapeutic agents. Herein, we provide an updated summary on the current knowledge of the fundamental chemical reactivity of benzoxaboroles, followed by highlighting their major applications reported to date.

The low keratin affinity of efinaconazole contributes to its nail penetration and fungicidal activity in topical onychomycosis treatment

Onychomycosis is a common fungal nail disease that is difficult to treat topically due to the deep location of the infection under the densely keratinized nail plate. Keratin affinity of topical drugs is an important physicochemical property impacting therapeutic efficacy. To be effective, topical drugs must penetrate the nail bed and retain their antifungal activity within the nail matrix, both of which are adversely affected by keratin binding. We investigated these properties for efinaconazole, a new topical antifungal for onychomycosis, compared with those of the existing topical drugs ciclopirox and amorolfine. The efinaconazole free-drug concentration in keratin suspensions was 14.3%, significantly higher than the concentrations of ciclopirox and amorolfine, which were 0.7% and 1.9%, respectively (P < 0.001). Efinaconazole was released from keratin at a higher proportion than in the reference drugs, with about half of the remaining keratin-bound efinaconazole removed after washing. In single-dose in vitro studies, efinaconazole penetrated full-thickness human nails into the receptor phase and also inhibited the growth of Trichophyton rubrum under the nail. In the presence of keratin, efinaconazole exhibited fungicidal activity against Trichophyton mentagrophytes comparable to that of amorolfine and superior to that of ciclopirox. In a guinea pig onychomycosis model with T. mentagrophytes infection, an efinaconazole solution significantly decreased nail fungal burden compared to that of ciclopirox and amorolfine lacquers (P < 0.01). These results suggest that the high nail permeability of efinaconazole and its potent fungicidal activity in the presence of keratin are related to its low keratin affinity, which may contribute to its efficacy in onychomycosis.

Safety and tolerability of luliconazole solution 10-percent in patients with moderate to severe distal subungual onychomycosis

The study objective was to evaluate the safety, tolerability, systemic exposure, and pharmacokinetics (PK) of 10% luliconazole solution (luliconazole) when topically applied once daily to all 10 toenails and periungual areas in patients with moderate to severe distal subungual onychomycosis. In this single-center, open-label study, 24 patients applied 20 mg/ml of luliconazole (twice the clinical dose) for 29 days with a 7-day follow-up. Complete PK profiles were determined on days 1, 8, 15, and 29. Safety/tolerability assessments included application site reactions, adverse events, vital signs, clinical laboratory findings, and electrocardiograms. Mean luliconazole plasma concentrations remained around the lower limit of quantitation (0.05 ng/ml) and were comparable on days 8, 15, and 29 (range, 0.063 to 0.090 ng/ml), suggesting steady state occurred by day 8. Every patient had undetectable plasma luliconazole levels for at least 11% of the time points, and 12 of the 24 patients had undetectable levels for at least 70% of the time points. The maximum plasma concentration of luliconazole (C(max)) observed in any patient was 0.314 ng/ml and the maximum area under the concentration-time curve from 0 to 24 h (AUC0-24) was 4.34 ng · h/ml. Five patients (21%) had measureable luliconazole levels in the plasma 7 days after the last dose. The median concentration of luliconazole in the nail at this time point was 34.65 mg/g (from 42 of 48 collected toenail samples). There was one mild incidence of skin erythema on day 5 that resolved on day 8, there were no reports of drug-induced systemic side effects, and there was no evidence of QT prolongation. Luliconazole, when applied once daily to all 10 fungus-infected toenails for 29 days, is generally safe and well tolerated and results in significant accumulation of drug in the nail. Systemic exposure is very low, with no evidence of drug accumulation.

Comparison of in vitro antifungal activities of efinaconazole and currently available antifungal agents against a variety of pathogenic fungi associated with onychomycosis

Onychomycosis is a common fungal nail infection in adults that is difficult to treat. The in vitro antifungal activity of efinaconazole, a novel triazole antifungal, was evaluated in recent clinical isolates of Trichophyton rubrum, Trichophyton mentagrophytes, and Candida albicans, common causative onychomycosis pathogens. In a comprehensive survey of 1,493 isolates, efinaconazole MICs against T. rubrum and T. mentagrophytes ranged from ≤ 0.002 to 0.06 μg/ml, with 90% of isolates inhibited (MIC90) at 0.008 and 0.015 μg/ml, respectively. Efinaconazole MICs against 105 C. albicans isolates ranged from ≤ 0.0005 to >0.25 μg/ml, with 50% of isolates inhibited (MIC50) by 0.001 and 0.004 μg/ml at 24 and 48 h, respectively. Efinaconazole potency against these organisms was similar to or greater than those of antifungal drugs currently used in onychomycosis, including amorolfine, ciclopirox, itraconazole, and terbinafine. In 13 T. rubrum toenail isolates from onychomycosis patients who were treated daily with topical efinaconazole for 48 weeks, there were no apparent increases in susceptibility, suggesting low potential for dermatophytes to develop resistance to efinaconazole. The activity of efinaconazole was further evaluated in another 8 dermatophyte, 15 nondermatophyte, and 10 yeast species (a total of 109 isolates from research repositories). Efinaconazole was active against Trichophyton, Microsporum, Epidermophyton, Acremonium, Fusarium, Paecilomyces, Pseudallescheria, Scopulariopsis, Aspergillus, Cryptococcus, Trichosporon, and Candida and compared favorably to other antifungal drugs. In conclusion, efinaconazole is a potent antifungal with a broad spectrum of activity that may have clinical applications in onychomycosis and other mycoses.

Histopathological periodic acid-schiff stains of nail clippings as a second-line diagnostic tool in onychomycosis

The diagnosis of onychomycosis, using direct microscopy and fungal cultures, is often negative despite the presence of disease. Periodic acid-Schiff (PAS) staining of nail clippings, using histopathological processing, may be positive in these cases. It is not always clear, however, whether the fungal elements detected by PAS staining are pathogenic fungi or some are saprophytes. We aimed to study the efficacy of histopathological PAS staining of nail clippings as a second-line diagnostic tool in onychomycosis. The study included 100 consecutive cases in which direct microscopy and fungal cultures from suspected onychomycosis were negative on one occasion or more. The obtained nail clippings were processed for routine histology, stained with hematoxylin and eosin and PAS, and examined microscopically. Of the 100 cases, 38 (38%) showed positive fungal elements. As a result, 9 patients had sought and received oral antifungal therapy and all achieved complete clinical cure. The histological examination also revealed parakeratosis and globules of plasma, which were statistically significantly more common in the fungal infected nail samples. This may indicate an ongoing inflammatory process associated with onychomycosis. Neutrophils and bacteria were not statistically and significantly more common in the fungal infected nails. We conclude that as a second-line diagnostic tool, PAS stain of nail clippings increases markedly the diagnostic yield of onychomycosis and, consequently, the outcome of therapy.

Efficacy, safety and tolerability of topical terbinafine nail solution in patients with mild-to-moderate toenail onychomycosis: results from three randomized studies using double-blind vehicle-controlled and open-label active-controlled designs

BACKGROUND

Terbinafine nail solution (TNS) was developed for the treatment of onychomycosis.

OBJECTIVE

To assess the efficacy of TNS vs. vehicle and amorolfine 5% nail lacquer.

METHODS

Subjects with mild-to-moderate toe onychomycosis (25% to ≤75% nail-involvement, matrix uninvolved) were randomized to receive either TNS or vehicle in two double-blind studies, and to TNS or amorolfine in an active-controlled, open-label study. Primary endpoint was complete cure (no residual clinical involvement and negative mycology) at week 52. Secondary endpoints were mycological cure (negative mycology defined as negative KOH microscopy and negative culture) and clinical effectiveness (≤10% residual-involvement and negative mycology) at week 52.

RESULTS

Complete cure was not different between TNS vs. vehicle and amorolfine. Mycological cure was higher with TNS vs. vehicle, as was clinical effectiveness with TNS vs. vehicle, and TNS and amorolfine were not different for secondary efficacy endpoints. Patients achieving mycological cure had a better clinical outcome, and efficacy was improved in subjects with milder disease. Post hoc analysis suggests that nail thickness is an important prognostic factor. Moreover, mycological cure may require 6 months of treatment regimen while complete cure and clinical effectiveness may be achievable only after 10 months. A simulation study suggests that longer treatment duration would have resulted in higher complete cure with TNS vs. vehicle. Study treatments were well-tolerated.

CONCLUSION

Primary efficacy objectives were not met in the studies reported herein. Possible reasons for failure to achieve significant outcomes include insufficient length of treatment; stringency of primary endpoint and severity of nail involvement of study population.

Antifungal activity and nail permeation of nail lacquer containing Piper regnellii (Miq.) C. CD. var. pallescens (C. DC.) Yunck (Piperaceae) leave extracts and derivatives

The dermatophytes are filamentous fungi that cause cutaneous fungal infections because they use keratin as a nutrient source. For this study the antidermatophyte activity of the extracts and derivates from leaves of Piper regnellii was analyzed. From the dichloromethane extract (EBD) neolignans such as eupomatenoid-3 and eupomatenoid-5 were obtained, and it was submitted to fractionation to remove the green residue, designated as the chloroform fraction (FF). Extracts, chloroform fraction and compounds were tested against Trichophyton rubrum ATCC 28189 to determine the minimum inhibitory concentration (MIC). The chloroform fraction was incorporated to nail lacquer that was analyzed by photoacoustic spectroscopy, In vitro assay and scanning electronic microscopy. For antifungal activity in solid medium the dichloromethane extract and chloroform fraction were used. The compounds eupomatenoid-3 and eupomatenoid-5 were less active than the dichloromethane extract against T. rubrum. EBD and FF showed moderate activity in hyphal growth inhibition in solid medium and EBD did not link to ergosterol. Nail lacquer containing the chloroform fraction showed good penetration through the nail as determined by photoacoustic spectroscopy. From In vitro studies it was observed that nail lacquer concentrations above 20 mg/mL prevented the growth of fungi, but concentrations up to 2.5 inhibited the growth. Scanning electronic microscopy was used to confirm the In vitro nail lacquer activity results. The specie P. regnellii showed great antifungal activity against T. rubrum, and nail lacquer containing its chloroform fraction has great potential to treat onychomycosis caused by these microorganisms.

[Antifungal agents for onychomycoses]

Nail fungal infections are considered one of the major dermatological problems due to their high rate of therapeutic failure, management and treatment difficulties. Long-term treatments, inadequate therapies, mycological misdiagnosis and follow-up, secondary alterations of the nail, and resistant microorganisms, are some of the causes of these complications. Although the discovery of new antifungal agents has provided some effective molecules, none of the current available drugs are totally effective. It is important to continue researching in this field to provide new antifungal agents and combined therapies.

Fatal Hepatitis After Long-Term Pulse Itraconazole Treatment for Onychomycosis

Objective:

To report the occurrence of acute cytolytic hepatitis In a patient exposed to pulse itraconazole therapy for 24 weeks and provide a concise review of the literature on cases of itraconazole-induced hepatitis.

Case Summary:

A 61 -year-old woman with no apparent risk factors for liver injury developed acute hepatitis one week after the final dose of a long-term course of pulse itraconazole therapy (200 mg orally twice daily, 1 wk on, 3 wk off, for 24 wk) for onychomycosis. Monitoring of liver enzymes was not performed during the treatment period. Serologic evaluations on presentation ruled out Infectious diseases or other etiological factors. Liver function tests showed alanine aminotransferase 3330 U/L, aspartate aminotransferase 3250 U/L, and bilirubin 21 mg/dL Liver function continued to deteriorate, and the patient underwent liver transplantation 17 days after admission. Her liver displayed reduced volume and them was a mild accumulation of ascitic fluid in the retroperitoneal cavity. Histologic evaluation showed massive panlobular necrosis. Complications occurred after transplantation and a rejection crisis worsened the clinical picture until the patient died about 4 months later. Use of the Naranjo probability scale showed the relationship of itraconazole therapy and the occurrence of acute hepatitis as probable.

Discussion:

Itraconazole pulse therapy for onychomycosis appears to be at least as effective as and safer than a continuous treatment regimen, particularly from the perspective of potential liver damage. Only one case of severe symptomatic hepatitis occurring after pulse therapy with itraconazole for onychomycosis and requiring transplantation has been reported previously. In that case, as well as the one reported here, hepatitis symptoms occurred after completion of long-term treatment in patients who were asymptomatic both before and during therapy.

Conclusions:

Prolonged exposure to itraconazole, administered either continuously or intermittently, may precipitate severe and irreversible hepatotoxic events. Accordingly, careful monitoring of liver function parameters should be performed both during and after treatment when onychomycosis requires prolonged itraconazole administration, even in asymptomatic patients lacking apparent risk factors of hepatic injury.

The significance of itraconazole for treatment of fungal infections of skin, nails and mucous membranes

Itraconazole is an antifungal drug from the triazole group with distinct in vitro activity against dermatophytes, yeasts and some molds. Itraconazole has a primarily fungistatic activity. Itraconazole accumulates in the stratum corneum and in nail material due to its high affinity to keratin, as well as in sebum and vaginal mucosa. Together with terbinafine and fluconazole, itraconazole belongs to the modern highly effective systemic antifungal drugs with a favorable risk-benefit ratio and for this reason is a preferred therapy option for fungal infections of skin, nails and mucous membranes. Compared to terbinafine in the treatment of fingernail and toenail fungal infections, itraconazole offers the advantage of a broad antifungal spectrum and better effectiveness against onychomycosis caused by yeasts yet appears inferior with regard to the more common dermatophyte infections. Itraconazole constitutes an important therapy option, along with fluconazole, terbinafine, ketoconazole and griseofulvin, for the treatment of dermatophyte infections of glabrous skin (tinea pedis, tinea manuum, tinea corporis and tinea cruris) in adults following unsuccessful topical therapy. In the oral therapy of tinea capitis, itraconazole plays an especially important role, in particular for disease caused by Microsporum canis (for children, however, only off-label use is feasible currently). In the treatment of oropharyngeal candidiasis, candidiasis of the skin and vulvovaginal candidiasis, itraconazole and fluconazole are the preferred treatment options in cases in which topical therapy has proven unsuccessful.

Use of diagnostic tests by dermatologists, podiatrists and family practitioners in the United States: pilot data from a cross-sectional survey

Before treating onychomycosis, it is important to exclude other conditions such as lichen planus and psoriasis. The purpose of this study was to evaluate physician preferences and uses of diagnostic tests for toenail onychomycosis (TO) by surveying dermatologists (D), podiatrists (P) and family practitioners (FP) in the United States. Surveys were mailed to approximately 1000 randomly sampled physicians from each of the three specialities. The questionnaire consisted of 15 items regarding physician and practice characteristics, number of patients with TO seen and treated, tests used to diagnose TO and reasons for using the tests. Results were analysed using several statistical methods. Response rates were low (D33.7%; P16.6%; FP28.4%). Ds and Ps (75.2%) and FPs (43.4%) reported feeling 'very confident' at diagnosing onychomycosis. KOH was the preferred diagnostic test for all three specialities. More Ds (75.4%) felt 'very confident' interpreting potassium hydroxide (KOH) exams than Ps (24.9%) and FPs (18.5%). Use of KOH exams was statistically associated with confidence interpreting exams (P P = 0.04092; D & FP P < 0.0001). Some FPs (46.6%) and Ps (21.6%) did not obtain a confirmatory diagnostic test prior to the treatment of onychomycosis while 63.6% of Ds 'almost always/always' did. While limited by low-response rate, this study provides pilot information on the diagnostic preferences for TO by American D, P and FP.

The effects of laser irradiation on Trichophyton rubrum growth

The effects of various laser wavelengths and fluences on the fungal isolate, Trichophyton rubrum, were examined in vitro. Standard-size isolates of T. rubrum were irradiated by using various laser systems. Colony areas were compared for growth inhibition on days 1, 3, and 6 after laser irradiation. Statistically significant growth inhibition of T. rubrum was detected in colonies treated with the 1,064-nm Q-switched Nd:YAG laser at 4 and 8 J/cm(2) and 532-nm Q-switched Nd:YAG laser at 8 J/cm(2). Q-switched Nd:YAG laser at 532- and 1,064-nm wavelengths produced significant inhibitory effect upon the fungal isolate T. rubrum in this in vitro study. However, more in vitro and in vivo studies are necessary to investigate if lasers would have a potential use in the treatment of fungal infections of skin and its adnexa.

Celulitis y onicomicosis proximal de ambos ortejos mayores producida por Fusarium solani

We report a case of proximal fold cellulitis in both big toes, associated with a bilateral proximal onychomycosis and an intertrigo of the fourth space due to Fusarium solani. The infection occurred in an immunocompetent man with diabetes mellitus type II. Apparently, the infection was acquired in a tropical country and once the patient was in Spain the infection progressed causing nail detachment (onychomadesis). Seven months later a relapse that affected the left toenail occurred. The patient was treated topically with chemical toenail avulsion contained 40% urea associated with bifonazole followed by ciclopirox-olamine nail lacquer for 12 months. Complete cure without relapse was observed after 10 years of follow-up. In vitro antifungal susceptibility study demonstrated that two of the recovered isolates were both resistant to itraconazole and voriconazole.

The top 10 things foot and ankle specialists wish every primary care physician knew

Foot and ankle problems are common complaints of patients presenting to primary care physicians. These problems range from minor disorders, such as ankle sprains, plantar fasciitis, bunions, and iIngrown toenails, to more serious conditions such as Charcot arthropathy and Achilles tendon rupture. Early recognition and treatment of foot and ankle problems are imperative to avoid associated morbidities. Primary care physicians can address many of these complaints successfully but should be cognizant of which patients should be referred to a foot and ankle specialist to prevent common short-term and long-term complications. This article provides evidence-based pearls to assist primary care physicians in providing optimal care for their patients with foot and ankle complaints.

[Histological diagnosis of onychomycosis]

It is mandatory to establish a firm diagnosis before starting systemic antimycotic therapy because of potential side effects and relatively high therapy costs. Direct microscopy and fungal culture are the most widely employed diagnostic tools. Not infrequently, a strong clinical suspicion cannot be proven by even repeated direct microscopic examinations and fungal cultures. In these cases histologic examination is a simple alternative. We identified 32 cases of histopathologically proven onychomycosis; of the 29 where a fungal culture was performed, only 14 (48%) were positive. Direct microscopy was performed only in 12 cases since most had repeatedly negative direct microscopy results before being referred to us; 5 cases (42%) were positive. Histopathology for onychomycosis has several advantages in addition to its sensitivity--particularly in difficult to diagnose cases: lack of the danger of contamination, a permanent preparation with the possibility to demonstrate fungal invasion of the nail organ and to identify other or concomitant nail disorders, simplicity of the procedure; quicker results as compared to fungal culture. Exact specification of the fungus is not possible with histology. Even though histological examination is not mentioned in the current guidelines for onychomycosis of the German Dermatological Society, it should be kept in mind as a simple but sensitive diagnostic tool.

Analysis of Dermatomycoses in Lanzhou District of Northwestern China

The skin mycoses, perticularly dermatophytoses, in Lanzhou district, Northwestern China, was investigated during July 2002-June 2003. The specimens from patients suspected of having dermatomycoses were examined microscopically in KOH preparations and cultured on Sabouraud dextrose agar (SDA). Among 1443 suspected cases, 594 were KOH positive and 221 cultures of fungi were isolated. The most frequently isolated fungi were Trichophyton rubrum (43.9%) Trichophyton mentagrophytes (29.4%) and Candida species (14.0%). The frequency of tinea pedis, onychomycosis and tinea manuum were 38.7, 27.8 and 13.5%, respectively. In Lanzhou district, tinea pedis is the most commonly seen dermatophytoses, and T. rubrum is the most frequent etiologic agent.

Dermatophytes in the rural area of Duzce, Turkey

A total of 227 subjects (112 were male and 115 female), who were residents of the rural region of Duzce, were examined for dermatomycosis. A total of 120 samples (47 nail fragments, 73 skin scales) were collected from 81 patients for mycological analysis on the basis of the results of clinical evaluation. All specimens collected were analysed by direct microscopy and culture. Positive results were detected in the cultures of 53 (44.1%) of the 120 samples. About 46 (86.7%) samples also presented positive results in direct microscopy. In the cases of seven samples positive results were found in culture and negative results with direct microscopy. Both culture and direct microscopy presented negative results in 67 (55.8%) samples. The most frequently isolated aetiological agents were 33 Trichophyton rubrum (62.2%), and nine T. mentagrophytes (16.9%). In conclusion, traditional and religious habits such as cohabitation and performing ritual ablutions may affect the prevalence of dermatophyte infections. The performance of ritual ablutions is not in itself a risk factor for acquiring dermatophyte infection; rather it is not drying the extremities after ablutions, that is the main risk factor for this group. Tinea capitis was not found in any of the subjects in spite of the fact that it is one of the most common infectious conditions in children. This is the first paper to report the prevalence of fungal infections in Duzce, a western Black Sea region of Turkey.

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.

A plea to bridge the gap between antifungals and the management of onychomycosis

Onychomycosis represents a stubborn problem for the clinician facing up to the realities of antifungal treatments. There are obvious discrepancies between data given by in vitro antifungal testings, pharmacodynamics and pharmacokinetics, and those gathered from clinical experience. This critical review is an attempt at bridging the gap between in vitro and in vivo information about oral antifungals that aim to treat onychomycoses. Common sense shows that the in vitro concept of fungicidy cannot be simply extrapolated into clinical practice. Indeed, chlamidoconidia and arthroconidia present in vivo are much more resistant to antifungals than hyphae. Corneofungimetry may be a realistic bioassay in predicting antifungal activity in human infections. Boosting hyphae growth from conidia while taking antifungals is a new and appealing treatment modality that deserves controlled study.