Current management of onychomycosis. An overview

Exploration of synergistically engineered invasomes of fluconazole incorporated with safranal against onychomycosis for enhanced transungual delivery

OBJECTIVE

The preparation of safranal-containing invasomes for fluconazole (FLU-IN) is investigated in the current research work to augment FLU permeation, bioavailability, and solubility via nail for transungual delivery.

METHODS

FLU-IN was prepared utilizing the 'thin-film hydration process', and for optimization, 'Box-Behnken design (BBD)' was employed. Entrapment efficiency (EE), Poly-dispersity index (PDI), in vitro FLU release, vesicle size and zeta potential were used to characterize FLU-INopt. Confocal microscopy (CLSM), nail permeation investigation, and Transmission electron microscopy (TEM) were also carried out for further examination.

RESULTS

The FLU-INopt demonstrated tiny, spherical, sealed-shape vesicles with a vesicle size of 140.3 nm, PDI of 0.1604, in vitro release of 84.32%, and entrapment efficiency of 74.65%. According to the CLSM investigation, the prepared formulation exhibits better FLU penetration over the nail than FLU suspension gel. Compared to the standard fluconazole marketed gel, the anti-fungal investigation showed that the FLU-IN gel has good anti-fungal potential against Trichophyton rubrum, Nakaseomyces glabrata and Candida albicans. Additional research on Wistar albino rats' skin irritancy supports the new FLU-IN formulation's safety for topical treatment.

CONCLUSION

The present study supported the claim that the developed invasomal formulation is a desirable vesicular carrier for FLU transungual delivery for the management of onychomycosis.

Linalool-Incorporated Synergistically Engineered Modified Liposomal Nanocarriers for Enhanced Transungual Delivery of Terbinafine against Onychomycosis

This work investigates the synthesis of linalool-containing invasomes for terbinafine (TBF-IN) in order to increase the solubility, bioavailability, and nail permeability of terbinafine (TBF) for transungual administration. TBF-IN was created utilising the thin-film hydration technique, and with the Box-Behnken design (BBD), optimisation was carried out. TBF-INopt were investigated for vesicle size, zeta potential, PDI (Polydispersity index), entrapment efficiency (EE) and in vitro TBF release. In addition, nail permeation analysis, TEM (transmission electron microscopy), and CLSM (confocal scanning laser microscopy) were performed for further evaluation. The TBF-INopt exhibited spherical as well as sealed vesicles with a considerably small size of 146.3 nm, an EE of 74.23 per cent, a PDI of 0.1612, and an in vitro release of 85.32 per cent. The CLSM investigation revealed that the new formulation had better TBF nail penetration than the TBF suspension gel. The antifungal investigation demonstrated that the TBF-IN gel has superior antifungal activity against Trichophyton rubrum and Candida albicans compared to the commercially available terbinafine gel. In addition, an investigation of skin irritation using Wistar albino rats indicates that the TBF-IN formulation is safe for topical treatment. This study confirmed that the invasomal vesicle formulation is an effective vehicle for the transungual delivery of TBF for the treatment of onychomycosis.

Investigation on Utility of Some Novel Terpenes on Transungual Delivery of Terbinafine for the Management of Onychomycosis

INTRODUCTION

Onychomycosis is a fungal disorder of the nail which afflicts 5% of the population worldwide. The disease is strenuous to cure as it is chronic, hard to eliminate and tends to recur. Topical therapy is at the forefront for the treatment of many disorders of nail. However, the success rate of topical therapy has been halted owing to the poor permeation of topical therapeutics across densely keratinized nail barrier. Therefore, ungual drug permeation must be improved for an effective topical therapy. An approach to achieve this goal would be the use of terpenes from natural sources as potential penetration enhancers.

OBJECTIVE

This study is aimed to explore the effectiveness of some novel terpenes as potential penetration enhancers on transungual delivery of terbinafine.

METHODS

Ex-vivo permeation studies were performed by sopping the nail clippings of healthy human volunteers in control and working solutions containing terbinafine (5mg/ml) per se and terbinafine (5mg/ml) with 6% of each terpenes including lavandulol, safranal, rose oxide, limonene, 3-methyl-2-butene-1-ol, and linalool respectively for 48 hours. The terbinafine concentration in nail samples was determined using a HPLC (High Performance Liquid Chromatography method.

RESULTS

Statistical analysis showed that studied terpenes increase transungual penetration of terbinafine in the following order: linalool > rose oxide > 3-methyl-2-butene-1-ol > safranal > limonene > lavandulol acetate. Accordingly, linalool was found to be the most effective penetration enhancer for the transungual delivery of terbinafine.

CONCLUSIONS

It is concluded that linalool can be used as safe and potential penetration enhancer for enhancing the transungual delivery of terbinafine for onychomycosis.

Investigation on utility of some novel terpenes on transungual delivery of fluconazole for the management of onychomycosis

BACKGROUND

Onychomycosis, the most prevailing affliction of the nail, accounts for approximately 90% of the toenail infection worldwide. Owing to this infection, the affected patients experience reduced quality of their life as its awful appearance undermines their daily activities and social interactions. Onychomycosis is notoriously strenuous to cure. Systemic therapy, though effective, possess severe complication of toxicities, contra-indication, and drug-drug interaction. Albeit topical therapy is favorable to its localized effect, its potency relates to the effective concentration of the antifungal drugs achieved at the infection site. An approach to accomplish this goal would be acquiring benefits from the terpenes as penetration enhancers from natural sources. This investigation aimed to study the effectiveness of six terpenes, namely safranal, lavandulol, rose oxide, 3-methyl-2-butene-1-ol, linalool, and limonene, as potential penetration enhancers for improved nail permeation of fluconazole through the human nail.

METHODS

Ex vivo permeation experiments were carried out by soaking the nail clippings of human volunteers in control and working solutions containing fluconazole (5 mg/ml) per se and fluconazole (5 mg/ml) with 6% of each terpene, including safranal, lavandulol, rose oxide, 3-methyl-2-butene-1-ol, linalool, and limonene, respectively, for 48 hours. The amount of fluconazole in nail clippings was quantified using an HPLC method.

RESULTS

Statistical analysis showed that fluconazole transungual permeation was influenced by the studied terpenes in the following order: safranal > lavandulol acetate > limonene > rose oxide (P-value > 0.05) while the other terpenes showed no significant difference with the control group and safranal represents as the most effective permeation enhancer for the transungual delivery of fluconazole.

CONCLUSION

It is concluded that the safranal can be successfully used as a safe and potential permeation enhancer to enhance the transungual delivery of fluconazole for the treatment of onychomycosis.

Treatment of Onychomycosis: Pros and Cons of Antifungal Agents

Background:

Antifungal agents are beneficial in the treatment of onychomycosis in the general population, as well as in children, the elderly, and immunocompromised individuals. Special patient populations can be more difficult to treat due to such factors as drug interactions with concomitant medications, adverse events, and poor compliance. In addition, there is limited information about the use of antifungal agents in special populations, e.g., children.

Objective:

The pros and cons of oral and topical antifungal agents are discussed, with focus on special patient populations.

Methods:

We searched MedLine (1966 to April 2003) for clinical studies evaluating the efficacy of oral and topical antifungal agents to treat onychomycosis. The key words used in conjunction with “onychomycosis” include: “terbinafine,” “itraconazole,” “fluconazole,” “amorolfine nail lacquer,” “ciclopirox nail lacquer,” “HIV,” “transplant patients,” “diabetes,” “children,” and “elderly.” Studies were excluded if published in a language other than English.

Results:

Studies have shown that antifungal agents can be of benefit in treating the elderly, children, and immunocompromised individuals (e.g., transplant patients, Down's patients, HIV patients, and diabetics) with onychomycosis.

Conclusion:

The treatment modality of onychomycosis in special patient populations should take into account the clinical presentation of the onychomycosis, the causative organism, patient and physician preference, the concomitant medications that the patient is on, and the potential for adverse events for that patient if antifungal therapy is undertaken.

Divergence of Antiangiogenic Activity and Hepatotoxicity of Different Stereoisomers of Itraconazole

PURPOSE

Itraconazole is a triazole antifungal drug that has recently been found to inhibit angiogenesis. Itraconazole is a relatively well-tolerated drug but shows hepatotoxicity in a small subset of patients. Itraconazole contains three chiral centers and the commercial itraconazole is composed of four cis-stereoisomers (named IT-A, IT-B, IT-C, and IT-D). We sought to determine whether the stereoisomers of itraconazole might differ in their antiangiogenic activity and hepatotoxicity.

EXPERIMENTAL DESIGN

We assessed in vitro antiangiogenic activity of itraconazole and each stereoisomer using human umbilical vein endothelial cell (HUVEC) proliferation and tube formation assays. We also determined their hepatotoxicity using primary human hepatocytes in vitro and a mouse model in vivo Mouse Matrigel plug and tumor xenograft models were used to evaluate in vivo antiangiogenic and antitumor activities of the stereoisomers.

RESULTS

Of the four stereoisomers contained in commercial itraconazole, we found that IT-A (2S,4R,2'R) and IT-C (2S,4R,2'S) were more potent for inhibition of angiogenesis than IT-B (2R,4S,2'R) and IT-D (2R,4S,2'S). Interestingly, IT-A and IT-B were more hepatotoxic than IT-C and IT-D. In mouse models, IT-C showed more potent antiangiogenic/antitumor activity with lower hepatotoxicity compared with itraconazole and IT-A.

CONCLUSIONS

These results demonstrate the segregation of influence of stereochemistry at different positions of itraconazole on its antiangiogenic activity and hepatotoxicity, with the 2 and 4 positions affecting the former and the 2' position affecting the latter. They also suggest that IT-C may be superior to the racemic mixture of itraconazole as an anticancer drug candidate due to its lower hepatotoxicity and improved antiangiogenic activity. Clin Cancer Res; 22(11); 2709-20. ©2016 AACR.

Controlled-release injectable containing terbinafine/PLGA microspheres for onychomycosis treatment

Controlled-release drug delivery systems based on biodegradable polymers have been extensively evaluated for use in localized drug delivery. In the present study, intralesionally injectable poly (lactide-co-glycolide) (PLGA) microspheres for controlled release of terbinafine hydrochloride (TH) was developed for treating fungal toe/finger nail infections. TH-PLGA microspheres were formulated using O/W emulsification and modified solvent extraction/evaporation technique. Microspheres were evaluated for particle size and size distribution, encapsulation efficiency, surface, and morphology. The in vitro drug release profile was studied in aqueous media as well as in 1% agar gel. Microspheres system was also evaluated in excised cadaver toe model, and extent of TH accumulation in nail bed, nail plate, and nail matrix was measured at different time points. Microspheres were found to provide consistent and sustained TH release. Intralesional administration of controlled-release microspheres can be a potential alternative mode of treating fungus-infected toe and/or finger nails.

Pharmacokinetics of orally administered terbinafine in African penguins (Spheniscus demersus) for potential treatment of aspergillosis

The objective of this study was to determine the pharmacokinetic parameters of orally administered terbinafine hydrochloride based on 3, 7, and 15 mg/kg single- as well as multiple-dosage trials in order to calculate dosing requirements for potential treatment of aspergillosis in African penguins (Spheniscus demersus). Ten adult African penguins were used in each of these trials, with a 2-wk washout period between trials. Mean plasma concentrations of terbinafine peaked in approximately 4 hrs at 0.11 +/- 0.017 microg/ml (mean +/- SD) following administration of 3 mg/kg terbinafine, while 7 mg/kg and 15 mg/kg dosages resulted in peak plasma concentrations of 0.37 +/- 0.105 and 0.33 +/- 0.054 microg/ml, respectively. The volume of distribution increased with increasing dosages, being 37 +/- 28.5, 40 +/- 28.1, and 52 +/- 18.6 mg/L for 3, 7, and 15 mg/kg doses, respectively. The mean half-life was biphasic with initial terminal half-life (t(1/2)) values of 9.9 +/- 4.5, 17.2 +/- 4.9 and 16.9 +/- 5.4 hrs, for 3, 7, and 15 mg/kg doses, respectively. A rapid first elimination phase was followed by a slower second phase, and final elimination was estimated to be 136 +/- 9.7 and 131 +/- 9.9 hrs, for 7 and 15 mg/kg doses, respectively. Linearity was demonstrated for area under the curve but not for peak plasma concentrations for the three dosages used. Calculations based on pharmacokinetic parameter values indicate that a 15 mg/kg terbinafine q24h dosage regimen would result in steady-state trough plasma concentrations above the minimum inhibitory concentration (0.8-1.6 microg/ ml), and this dosage is recommended as a potential treatment option for aspergillosis in penguins. However, additional research is required to determine both treatment efficacy and safety.

Two novel itraconazole pulse therapies for onychomycosis: A 2‐year follow‐up

BACKGROUND

Itraconazole given in pulse therapy has become popular for onychomycosis treatment since it results in less plasma exposure to the drug while maintaining an effective drug concentration in the nail plate and also increasing patient compliance.

OBJECTIVE

The current study aims to evaluate two different regimens of itraconazole for toenail onychomycosis, looking at both the immediate post-therapy cure rate and the relapse rate after 2 years.

METHODS

Two groups of 52 patients each were given either 'standard' oral itraconazole pulse therapy for 3 months (200 mg x 2/day for 1 week/month) followed by an additional single course (200 mg/day for 7 days) after 3 months (regimen A) or 'modified' (6-week interval) itraconazole pulse therapy x3 followed by an additional single course (200 mg x 2/day for 7 days) after 3 months. All patients were followed-up for 24 months from the beginning of treatment.

RESULTS

Regimen A: 37 patients were available for examination after 24 months, of whom 22 patients (59.5%) had total cure and two patients (5.5%) had marked improvement. Regimen B: 38 patients were available for examination after 24 months, of whom 29 patients (76.3%) had total cure and three patients (7.9%) had marked improvement. There were no statistical differences in cure rates between the two groups at the end of treatment, after 12 months and after 24 months. None of the patients (in both treatment groups) who had total cure at the end of the treatment period had onychomycosis recurrence after 12 or 24 months.

CONCLUSION

The results at the end of the 24-month period are encouraging, where 64.9% (regimen A) and 84.2% (regimen B) of the patients had total cure or marked improvement in their toenail condition. Therefore, those two regimens are acceptable alternatives to the current treatment regimen.

Diagnosis of Trichophyton rubrum from onychomycotic nail samples using polymerase chain reaction and calcofluor white microscopy

BACKGROUND

A high rate of false-negative dermatophyte detection is observed when the most common laboratory methods are used. These methods include microscopic observation of potassium hydroxide-digested nail clippings and culture methods using agar-based media supplemented with cycloheximide, chloramphenicol, and gentamicin to isolate dermatophytes. Microscopic detection methods that use calcofluor white staining or periodic acid-Schiff staining may also be substituted for and have previously been reported to be more sensitive than potassium hydroxide-digested nail clippings.

METHODS

Trichophyton rubrum infections were detected directly from nails in a double-round polymerase chain reaction assay that uses actin gene-based primers. This method was compared with detection of fungal hyphae by using calcofluor white fluorescence microscopy of nail samples collected from 83 patients with onychomycosis who were undergoing antifungal drug therapy.

RESULTS

Twenty-six of 83 samples (31.3%) were found to be positive by calcofluor white fluorescence microscopy, and 21 of 83 samples (25.3%) yielded positive results for T rubrum when actin gene-based primers in a double-round polymerase chain reaction assay were used. When calcofluor white fluorescence microscopy and polymerase chain reaction assay were used, the combined detection was 46.9% compared with 31.3% when calcofluor microscopy and culture of nail samples on Sabouraud's dextrose agar supplemented with cycloheximide, chloramphenicol, and gentamicin were used.

CONCLUSIONS

These results suggest that the use of a direct DNA protocol is an alternative method for detecting Trichophyton infections. When this protocol is used, the presence of T rubrum DNA is directly detected. However, the viability of the dermatophyte is not addressed, and further methods need to be developed for the detection of viable T rubrum directly from nail samples.

Fast and sensitive detection of Trichophyton rubrum DNA from the nail samples of patients with onychomycosis by a double-round polymerase chain reaction-based assay

BACKGROUND

Trichophyton rubrum is one of the most frequently isolated pathogens in onychomycosis. Isolation of T. rubrum from nail samples by traditional methods is time-consuming and has a high false-negative rate of detection.

OBJECTIVES

To investigate the detection of T. rubrum in nail samples using DNA detection methods.

METHODS

A total of 62 nail samples from onychomycosis patients with T. rubrum infection were evaluated by culture on Sabouraud's dextrose agar plus chloramphenicol, cycloheximide and gentamicin and compared with genotyping methods utilizing DNA extracted directly from nails. Trichophyton rubrum DNA isolated directly from nails was amplified using two different conserved regions [actin gene and internal transcribed spacer 1 (ITS)] in double-round polymerase chain reaction (PCR) assays.

RESULTS

Forty-eight of 62 (77.4%) samples were potassium hydroxide (KOH) positive, but T. rubrum culture was positive in only 14 of 62 (22.6%) samples. By contrast, direct T. rubrum DNA detection rate was 59.7% (37/62) by actin gene and 45.2% (28/62) by ITS1 region PCR assays corresponding to higher detection frequencies compared with culture with P < 0.001 and < 0.008, respectively. The combined detection of actin and ITS1 was 69.4% (43/62). Interestingly, T. rubrum DNA was detected in 9 out of 14 (64.3%) of KOH- and culture-negative samples. Importantly, 15 culture-negative samples collected from patients undergoing antifungal treatment tested PCR positive using the actin region.

CONCLUSIONS

These results suggest that a direct DNA detection protocol is more sensitive, accurate and faster than traditional culture-based methods. It can be useful to detect T. rubrum in patients undergoing antifungal therapy and who have been reported mycologically cured on the basis of a culture-based method.

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.

Topical antifungal drugs for the treatment of onychomycosis: an overview of current strategies for monotherapy and combination therapy

BACKGROUND

Onychomycosis is a relatively common disease accounting for up to 50% of all nail disorders and its prevalence rises with age. As onychomycosis is an important medical disorder affecting both patient's health and quality of life, it requires prompt and effective treatment.

OBJECTIVE

Topical antifungal nail lacquers have been formulated to provide efficient delivery to the nail unit. As both amorolfine and ciclopirox have proved useful as monotherapy for onychomycosis that does not involve the nail matrix area, the purpose of this article is to check if, when combined with oral agents, the effectiveness and scope of treatment can be improved further.

METHODS

Combining data for mycological cure with clinical success (nail morphology) provides a more exacting efficacy measure.

RESULTS

Clinical investigations have shown that the combination of oral therapies with antifungal nail lacquer can confer considerable advantage over monotherapy with either drug type.

CONCLUSION

The improved effectiveness and economic advantages of combined topical/oral therapies benefit both patients and health providers; these treatment regimens therefore have an important role to play in the modern management of onychomycosis.

Onicomicose na infância: uma perspectiva atual com ênfase na revisão do tratamento

A prevalência da onicomicose na infância, principalmente quando provocada por dermatófitos e Candida sp, tem aumentado. Tais infecções em crianças parecem infreqüentes em países desenvolvidos, mas não são excepcionais na América Latina. O objetivo principal deste trabalho foi analisar a literatura médica atual. Foi observada a onicomicose por dermatófitos em crianças com idade a partir de dois anos. A faixa entre 12-16 anos é a mais afetada (66,4%), provavelmente devido aos fatores de risco aumentado, como a prática de esportes e os hormônios da puberdade. Os pais foram a fonte de infecção em 46,2% dos casos, e 65% dos parentes de pacientes apresentavam onicomicose ou tinea pedis. As unhas dos dedos dos pés são afetadas por dermatófitos, sendo mais freqüente a onicomicose distal subungueal (88,5%); contudo, também se observam as formas superficial branca e branca subungueal proximal. A suspeita de diagnóstico é obtida com o exame clínico, mas a confirmação micológica é necessária. Os principais agentes dermatófitos são: T. rubrum (69%-92,7%), T. tonsurans (8,8%), T. mentagrophytes var interdigitale (5,4%) e M. canis (2,9%). A griseofulvina constitui o tratamento de primeira linha, mas itraconazol, fluconazol e terbinafina também são recomendados para o tratamento sistêmico. O tratamento tópico com ciclopirox a 8%, amorolfina a 5% e uréia a 40% associada a bifonazol a 1% pode ser considerado alternativa terapêutica. Dada a escassez de relatos de onicomicose em crianças, não foi possível uma conclusão sobre a melhor abordagem terapêutica. Mais dados clínicos são necessários para estabelecer o perfil de segurança dos novos agentes antimicóticos a fim de determinar a conduta ideal na onicomicose infantil.

How to improve cure rates for the management of onychomycosis

To improve the treatment of onychomycosis clinicians need to identify correctly the causative organism, choose a therapy that is effective against the pathogen, and take into consideration the pharmacokinetics (eg, bioavailability, drug interactions) of the oral agent. In addition, variations of the standard regimens may need to be considered (ie, booster or supplemental therapy). To reduce the recurrence of onychomycosis, once mycologic cure has been achieved, clinicians should educate their patients about proper foot care. Familiarity with the symptoms and signs of tinea pedis and onychomycosis may enable patients to seek appropriate care when the disease is at an early stage.

Antifungal therapy--state of the art at the beginning of the 21st century

The most relevant information on the present state of the art of antifungal chemotherapy is reviewed in this chapter. For dermatomycoses a variety of topical antifungals are available, and safe and efficacious systemic treatment, especially with the fungicidal drug terbinafine, is possible. The duration of treatment can be drastically reduced. Substantial progress in the armamentarium of drugs for invasive fungal infections has been made, and a new class of antifungals, echinocandins, is now in clinical use. The following drugs in oral and/or intravenous formulations are available: the broad spectrum polyene amphotericin B with its new "clothes"; the sterol biosynthesis inhibitors fluconazole, itraconazole, and voriconazole; the glucan synthase inhibitor caspofungin; and the combination partner flucytosine. New therapy schedules have been studied; combination therapy has found a significant place in the treatment of severely compromised patients, and the field of prevention and empiric therapy is fast moving. Guidelines exist nowadays for the treatment of various fungal diseases and maintenance therapy. New approaches interfering with host defenses or pathogenicity of fungal cells are being investigated, and molecular biologists are looking for new targets studying the genomics of pathogenic fungi.

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.

Onychomycosis: strategies to improve efficacy and reduce recurrence

Fungal infections may be difficult to treat for several reasons. It is important to obtain the correct diagnosis, and select the appropriate antifungal agent and route. General considerations that may be associated with recurrent infections are, a genetic predisposition and suboptimal bioavailability of drug, resulting in insufficient concentration at the target site. The aetiologic organism, the severity of disease, other coexisting diseases, concomitant drug intake, and the presence of fungal infection at other sites are some factors that determine the choice of antifungal therapy and its route of administration, oral vs. topical lacquer. Local factors such as the thickness of the nail, presence of lateral onychomycosis, longitudinal spike, dermatophytoma and severe onycholysis are some factors that may determine the choice of secondary measures such as mechanical or topical treatment. Booster or supplemental therapy may be of benefit when the response to initial treatment is poorer than expected and unlikely to result in complete response. Steps should be taken to reduce the possibility of recurrence once cure has been achieved.

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.

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.

Current management of fungal infections

The management of superficial fungal infections differs significantly from the management of systemic fungal infections. Most superficial infections are treated with topical antifungal agents, the choice of agent being determined by the site and extent of the infection and by the causative organism, which is usually readily identifiable. One exception is onychomycosis, which usually requires treatment with systemically available antifungals; the accumulation of terbinafine and itraconazole in keratinous tissues makes them ideal agents for the treatment of onychomycosis. Oral candidiasis in immunocompromised patients also requires systemic treatment; oral fluconazole and itraconazole oral solution are highly effective in this setting. Systemic fungal infections are difficult to diagnose and are usually managed with prophylaxis or empirical therapy. Fluconazole and itraconazole are widely used in chemoprophylaxis because of their favourable oral bioavailability and safety profiles. In empirical therapy, lipid-associated formulations of amphotericin-B and intravenous itraconazole are safer than, and at least as effective as, conventional amphotericin-B (the former gold standard). The high acquisition costs of the lipid-associated formulations of amphotericin-B have limited their use.

Single-blind, randomized, prospective study of sequential itraconazole and terbinafine pulse compared with terbinafine pulse for the treatment of toenail onychomycosis

OBJECTIVE

Efficacy and safety of sequential pulse therapy with itraconazole and terbinafine were compared with pulse terbinafine alone in the treatment of toenail onychomycosis.

METHODS

This was a 72-week prospective, single-blind, randomized, multicenter, comparative, parallel group, nonindustry-sponsored trial. A total of 190 patients were recruited from 3 outpatient dermatology offices in North America. Patients were at least 18 years old and had a clinical and mycologic diagnosis of dermatophyte toenail onychomycosis. Patients were randomly assigned to receive sequential pulse therapy (IIT) with 2 pulses of itraconazole followed by 1 or 2 pulses of terbinafine (itraconazole pulse is 200 mg twice daily for 1 week and terbinafine pulse is 250 mg twice daily for 1 week) versus 3 or 4 pulses of terbinafine (TTT). Main outcome measures at week 72 evaluated mycologic cure rate (negative light microscopy and culture), clinical cure (nail appears completely or totally normal), complete cure (clinical and mycologic cure), and effective therapy (mycologic cure and clinical response with at least 5 mm of new, uninvolved nail growth).

RESULTS

At week 72, in the IIT versus TTT groups, the mycologic cure rate was 54 of 75 (72.0%) versus 44 of 90 (48.9%), clinical cure rate was 42 of 75 (56.0%) versus 35 of 90 (38.9%), effective therapy 49 of 75 (65.3%) versus 41 of 90 (45.6%), and complete cure 39 of 75 (52.0%) versus 29 of 90 (32.2%), respectively. Both regimens were well tolerated with no new adverse effects being identified. The rate of permanent discontinuation of therapy because of adverse effects was 2 of 81 (2.5%) with IIT and 2 of 95 (2.1%) with TTT. Each of the adverse effects normalized over time. The number of patients who reported an adverse effect in the 2 groups was 12 of 81 (14.8%) versus 22 of 95 (23.2%), respectively. All these adverse effects were reversible and mild to moderate in severity.

CONCLUSION

Sequential pulse therapy with itraconazole and terbinafine is effective and safe for the treatment of dermatophyte toenail onychomycosis.

Cost of treatment for onychomycosis. Data from a 9-month observational study

OBJECTIVES

To estimate component and total costs of treatment and to examine differences in cost and cost effectiveness between oral antifungal medication and local therapy for patients with toenail onychomycosis.

DESIGN

Prospective, observational study of patients with onychomycosis who visited dermatologists and podiatrists in the US. Physicians provided data on clinical management, disease severity, nail improvement and resource utilisation. Patients completed questionnaires on resource utilisation and symptoms at base-line, 4 and 9 months. To estimate costs, reported utilisation was multiplied by unit costs expressed in 1997 US dollars ($US) and derived in 2 ways: first, using Medicare fees; and second, using standard physician fees.

RESULTS

After adjustment for key demographic and clinical variables, participants receiving oral medication had higher total costs based on standard fees ($US794 vs $US575) and medication costs ($US564 vs $US109), lower procedure costs ($US0 vs $US122) and physician visit costs ($US200 vs $US330), and greater clinical effectiveness as measured by global improvement rating (86 vs 35%) and Toenail Symptom Index (94 vs 49%). For participants receiving oral medication, 90% of total costs were incurred during the first 4 months of follow-up, whereas for those receiving local therapy, costs were more evenly distributed throughout the study period. Incremental cost-effectiveness analysis showed $US304 to $US491 per additional case improved with oral medication over a 9-month timeframe. Extrapolation of these results using 2 time-points (months 4 and 9) suggested that cost equivalence would be reached 17 to 21 months following the initiation of treatment.

CONCLUSIONS

During 9 months of follow-up in patients with toenail onychomycosis, the use of oral antifungal medication resulted in superior patient outcomes, but at higher total cost compared with local therapy.

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.

Ciclopirox nail lacquer topical solution 8% in the treatment of toenail onychomycosis

BACKGROUND

Onychomycosis is a relatively common condition affecting toenails more than fingernails. It is caused predominantly by dermatophytes. Onychomycosis can cause pain and discomfort and has the potential to be a source of morbidity.

OBJECTIVE

We evaluated the efficacy and safety of ciclopirox nail lacquer solution 8% used to treat onychomycosis of the toe in the United States and in centers worldwide.

METHODS

Two identically designed, double-blind, vehicle controlled, parallel group multicenter studies were performed in the United States to evaluate the use of ciclopirox nail lacquer to treat mild to moderate toe onychomycosis caused by dermatophytes. In the first study, 223 patients were randomized to treatment (ciclopirox group: 112, vehicle group: 111), and in the second study, 237 subjects were randomized (ciclopirox group: 119, vehicle group: 118). Before randomization, patients were to have clinical features of onychomycosis in at least one great toe with positive light microscopic examination and a positive dermatophyte culture. The test material was applied daily for a period of 48 weeks to all toenails and affected fingernails, covering the entire nail plate and approximately 5 mm of surrounding skin. At baseline, subjects had between 20% to 65% area of target nail involved. Physician's assessments were carried out every 4 weeks, and mycologic evaluation and photographic planimetry using standardized photographs were performed every 12 weeks during the 48 weeks of treatment. In studies conducted outside the United States, patients were also to have clinical, microscopic, and culture evidence of onychomycosis. However, these studies included some patients infected with nondermatophyte organisms (eg, Candida species), and the area of nail involvement was generally greater than observed in the US studies. Treatment regimens also varied in the non-US studies with lacquer applications that were sometimes less frequent than the once daily treatment used in the US studies (eg, alternate day or twice weekly). In addition, the typical duration of treatment was 6 months in the non-US studies as compared with 48 weeks in the United States. Outcome measures were similar to those used in the US trials, although a non-photographic planimetric method was used to quantify disease extent.

RESULTS

Data from the pivotal US trials have demonstrated that ciclopirox nail lacquer 8% topical solution is significantly more effective than placebo in the treatment of onychomycosis caused by Trichophyton rubrum, and of mild to moderate toe onychomycosis without lunula involvement. At the end of the 48-week treatment period, the mycologic cure rate (negative culture and negative light microscopy) in study I was 29% vs 11% in the ciclopirox and vehicle groups, respectively. Similarly, the mycologic cure rate for study II was 36% vs 9%, respectively. In the non-US studies, the mycologic cure rates ranged from 46.7% to 85.7%. In addition, ciclopirox nail lacquer has demonstrated a broad spectrum of activity with efficacy against Candida species and some nondermatophytes in non-US studies. Ciclopirox nail lacquer is considered extremely safe regarding causally related treatment emergent adverse-effects (TEAEs), with most TFAEs transient and localized to the site of action (eg, erythema and application site reaction). In the US studies, TFAEs were generally mild and cleared while the patient continued to use the nail lacquer.

CONCLUSIONS

Studies conducted worldwide demonstrate the efficacy of ciclopirox nail lacquer for the treatment of finger and toe onychomycosis. Both controlled and open-label studies confirm the excellent safety profile of this topical therapy. Thus, the nail lacquer provides a treatment choice with a favorable benefit-to-risk ratio. With its novel mechanism of action and its topical route of administration, ciclopirox nail lacquer offers an innovative approach to the treatment of this often difficult-to-manage disease

A randomized trial of amorolfine 5% solution nail lacquer combined with oral terbinafine compared with terbinafine alone in the treatment of dermatophytic toenail onychomycoses affecting the matrix region

In view of recent advances in the development of antifungal agents, this study examined the possible synergy of two new antifungal agents, terbinafine and amorolfine. The study compared two different courses of terbinafine treatment combined with amorolfine 5% solution nail lacquer. Terbinafine was given orally for 6 (AT6 group) or 12 weeks (AT12 group) and amorolfine nail lacquer applied weekly for 15 months. A control group received terbinafine alone for 12 weeks. This was a randomized, prospective, open study of severe dermatophyte toenail onychomycosis with matrix region involvement. Nail samples were taken before the start of the study, at inclusion and at the visits at 6 weeks, 3, 9, 15 and 18 months. To assess the value of such combined therapy we chose an early parameter as the principal outcome variable, which was the result of mycological examination, including direct microscopy and culture, at 3 months (allowing a margin of 15 days). The secondary parameters of success were the mycological results at the later visits, clinical evaluation and a combined mycological-clinical response. Safety and tolerance were also assessed. Adverse events were recorded and liver function tests were performed monthly during the terbinafine treatment. Of the 147 patients included in the trial, 121 attended the 3-month visit, within a time limit of 15 days of 3 months after the beginning of treatment: 40 in the AT6 group, 40 in the AT12 group and 41 in the control group. In all, 32 of 121 patients (26. 4%) had negative mycological results on direct microscopy and culture: 14 of 40 (35.0%) in the AT6 group, 11 of 40 (27.5%) in the AT12 group and seven of 41 (17.1%) in the control group. The cure rate for the global (mycological and clinical cure) response measured at 18 months in 145 patients was 44.0% (22 patients) in the AT6 group, 72.3% (34 patients) in the AT12 group and 37.5% (18 patients) in the terbinafine group. These results suggest that the combination of amorolfine and terbinafine may be of value in the treatment of severe onychomycosis. At the same time a pilot pharmacoeconomic analysis was performed demonstrating a better cost per cure ratio for the patients receiving combination treatment.

Onychomycosis in the elderly

Onychomycosis is found more frequently in the elderly, and in more males than females. Onychomycosis of the toes is usually caused by dermatophytes, most commonly Trichophyton rubrum and T. mentagrophytes. The most common clinical presentations are distal and lateral subungual onychomycosis (which usually affects the great/first toe) and white superficial onychomycosis (which generally involves the third/fourth toes). Only about 50% of all abnormal-appearing nails are due to onychomycosis. In the remainder, trauma to the nail, psoriasis and conditions such as lichen planus should be considered in the differential diagnosis. Therefore, the clinical impression of onychomycosis should be confirmed by mycological examination, whenever possible. The management of onychomycosis may include no therapy, palliative treatment with mechanical or chemical debridement, topical antifungal therapy, oral antifungal agents or a combination of treatment modalities. In the US, the only new oral agents approved for treatment of onychomycosis are terbinafine and itraconazole. Fluconazole is approved for onychomycosis in some other countries. Ciclopirox nail lacquer has recently been approved in the US for the treatment of onychomycosis. In some other countries topical agents such as amorolfine are also used. Griseofulvin and ketoconazole are no longer preferred for the treatment of onychomycosis. The new oral antifungal agents are effective and well tolerated in the elderly. Patient selection should be based on the history (including systems review and medication record), examination and baseline monitoring, if indicated. Laboratory monitoring during therapy for onychomycosis varies among physicians. A combination of removal of the diseased nail plate or local measures and oral antifungal therapy may be optimal in certain instances, e.g. when lateral onychomycosis or dermatophytoma are present. For dermatophyte toe onychomycosis the recommended duration of therapy with terbinafine is 250 mg/day for 12 weeks. For itraconazole (pulse) the regimen is 200 mg twice daily for 1 week on, 3 weeks off, repeated for 3 consecutive pulses and with fluconazole the regimen is 150 to 300 mg once weekly given for a usual range of 6 to 12 months or until the nail plate has grown out. In some instances, if extra therapy is required, one suggestion is that 4 weeks of terbinafine or an extra pulse of itraconazole are given between months 6 and 9 from the start of therapy. Once cure has been achieved, it is important to counsel patients on the strategies of reducing recurrence of disease.

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.

Onychomycosis: therapeutic update

Onychomycosis is a common disease of the nail unit caused by dermatophytes, yeasts, and molds. In more than 80% of cases, onychomycosis is caused by the dermatophytes Trichophyton rubrum and Trichophyton mentagrophytes. The prevalence of onychomycosis in the world's population is 2% to 18% or higher and accounts for approximately 50% of all nail disorders. Until recently, available therapies were inadequate because of low cure rates, high relapse rates, and often dangerous side effects. An increased understanding of nail pharmacokinetics has led to the development of safer, more effective systemic therapies for onychomycosis, such as itraconazole, fluconazole, and terbinafine. These new oral antifungal agents allow shorter periods of treatment, provide rapid efficacy, and may improve patient compliance and attitudes regarding therapy. Treatment selection will depend on several factors, including appropriate spectrum of activity, adverse effects, and potential drug interactions plus patient preferences for specific dosing regimens.

Factors that may affect the response of onychomycosis to oral antifungal therapy

With the advent of the newer oral antifungals available to treat onychomycosis, the majority of patients respond to therapy. However, there may be subsets of patients who exhibit poor response or failure. Possible explanations for this may be grouped into categories, including: (i) patient characteristics; (ii) organisms causing or associated with the nail infection; (iii) nail characteristics; and (iv) local diseases involving the nail.

Onychomycosis in children: prevalence and treatment strategies

BACKGROUND

Onychomycosis is observed less frequently in children than adults. Until recently management of onychomycosis in children included topical formulations, oral griseofulvin, and in some cases deferral of treatment.

OBJECTIVE

We attempted to determine the prevalence of onychomycosis in North American children 18 years old or younger attending our dermatology offices (three Canadian, two U.S.) and to report the group's experience using fluconazole, itraconazole, and terbinafine for onychomycosis.

METHODS

We undertook a prospective, multicenter survey in which all children, regardless of presenting complaint, were examined for onychomycosis by a dermatologist. In instances of clinical suspicion appropriate nail samples were obtained for light microscopy and culture.

RESULTS

A total of 2500 children under age 18 were examined in the five-center survey (1117 males and 1383 females, mean +/- S.E. age: 11.2 +/- 0.1 years). There was one child with fingernail and ten with mycologically confirmed toenail dermatophyte onychomycosis. The overall prevalence of onychomycosis was 0.44%. Considering those children whose primary or referring diagnosis was not onychomycosis or tinea pedis, the prevalence of onychomycosis was 0.16%. Outside the survey we have seen six other children with dermatophyte onychomycosis; these 17 cases form the basis for the remainder of the report. Of the 17 children, eight (47%) had concomitant tinea pedis infection, and in 11 (65%) a sibling, parent, or grandparent had onychomycosis or tinea pedis. Management included topical terbinafine (two patients: one cured, one failed therapy), topical ketoconazole (one patient: clinical improvement), oral fluconazole (two patients: one cured, one had Down's syndrome and was noncompliant), oral itraconazole (four patients: three cured with subsequent recurrence at follow-up in one patient, one lost to follow-up), oral terbinafine (five patients: four cured with subsequent recurrence at follow-up in one patient, one failed therapy). One child received no therapy following discussion with the parents, one was lost to follow-up and one was found to have asymptomatic hepatic dysfunction with hepatitis C at pretherapy bloodwork.

CONCLUSION

The prevalence of onychomycosis in our sample of North American children 18 years old or younger was 0.44% (n = 2500). In the subset of children whose primary or referring diagnosis was not onychomycosis, the prevalence of onychomycosis was 0.16%. Children with onychomycosis should be carefully examined for concomitant tinea pedis, and their parents and siblings checked for onychomycosis and tinea pedis. The newer oral antifungal agents fluconazole, itraconazole, and terbinafine may be effective and well-tolerated in the treatment of onychomycosis in this age group. These drugs should be carefully evaluated in a larger cohort of children with onychomycosis.