Response to initial griseofulvin therapy in pediatric patients with tinea capitis

Treatment of tinea capitis with topical 1% encapsulated terbinafine hydrochloride gel: A pilot study

BACKGROUND/OBJECTIVE

Oral antifungal agents are the mainstay of the therapy of pediatric tinea capitis. No approved topical medications for tinea capitis are found. We evaluated the therapeutic efficacy, safety, and tolerability of topical 1% encapsulated terbinafine hydrochloride gel for the treatment of pediatric tinea capitis.

METHODS

An open-label clinical trial was performed on 10 children with clinical and mycologically confirmed diagnosis of tinea capitis. Each child was prescribed topical 1% encapsulated terbinafine hydrochloride gel to be applied twice daily to the full scalp for 4 weeks. Clinical and mycological examinations were assessed 2 weeks after completion of treatment. Monitoring was performed for associated side effects during the treatment and follow-up periods.

RESULTS

Ten male patients were enrolled with a mean age of 10.3 years. A cure rate of 80% (n = 8) was noted 2 weeks after treatment completion. An additional 20% (n = 2) had mycological cure with incomplete, but significant clinical improvement. No significant side effects were reported.

CONCLUSIONS

This preliminary study demonstrated that topical 1% encapsulated terbinafine hydrochloride gel was an effective treatment for tinea capitis in children.

Treatment of Tinea Capitis

Tinea capitis is a common fungal infection of the hair of the scalp affecting predominately prepubertal children. In the US, griseofulvin has been considered a first-line therapy agent for tinea capitis since the 1960s. However, it has been falling out of favor due to significant treatment failure, high cost, and long duration of treatment. Other antifungal agents have been researched as an alternative to griseofulvin. This paper will review the relevant pharmacologic properties, dosing, cost, efficacy, and adverse events profile for griseofulvin, terbinafine, itraconazole, fluconazole, and some adjuvant therapy options such as selenium sulfide shampoos and topical ketoconazole.

Griseofulvin Only Modestly Diminishes Persistence of Trichophyton tonsurans on the Scalp of Carriers

OBJECTIVES

Using genetic strain typing, we previously identified a high rate of T. tonsurans carriage among preschool-aged children attending an urban daycare center. No treatment was provided as part of the observational study; however, children when symptomatic were treated in accordance with daycare policies. This retrospective investigation examines antifungal drug therapy received during the previous investigation and characterizes the impact of treatment on persistence of the fungus on the scalp.

METHODS

Children in whom serial typeable isolates of T. tonsurans were recovered were eligible for evaluation. Clinic charts were reviewed and dispensing records obtained from the primary pharmacies serving the daycare. Infection patterns were examined before and after treatment.

RESULTS

We identified 72 dispensing records for 53 children, all of whom received griseofulvin. Nine children could not be evaluated because treatment was coincident with their last study visit. Thus, 63 treatment events in 44 children with 331 discrete infection events remained. After a single course of griseofulvin, 22.7% of children became culture negative, 6.8% acquired another strain of T. tonsurans and, 70.5% remained persistently positive with the same strain carried prior to treatment. Among those receiving a second course of therapy, 54% remained positive and the cumulative percent of children that became culture negative increased to 36.4%. If children subsequently acquiring a different strain are considered together with those that became culture negative, cumulative strain clearance was observed in 43% of children. Neither the griseofulvin dose nor the duration of time over which children were infected prior to treatment differed between those that remained positive and those that became negative.

CONCLUSIONS

Griseofulvin eradicates dermatophyte scalp carriage in less than one-half of preschool-aged children receiving between one and four 4-week courses of the drug.

Tinea capitis: predictive value of symptoms and time to cure with griseofulvin treatment

OBJECTIVES

To describe (a) the predictive value of symptoms for diagnosis of tinea capitis and (b) the rate and timing of cure with high-dose griseofulvin treatment.

METHODS

This prospective open-label study enrolled children aged 1 to 12 years with clinical tinea capitis. Participants with a positive dermatophyte culture received oral griseofulvin (20-25 mg/kg/day) and topical selenium sulfide shampoo for 6 weeks. Main outcome measures. The rate of symptoms of tinea capitis, and rates of mycologic and clinical cure.

RESULTS

The positive predictive values of any 1, 2, 3, or 4 symptoms for a positive culture were 88%, 82%, 78%, and 77%, respectively. The observed rates of mycologic, clinical, and complete cure were 89%, 66%, and 49%, respectively. conclusion: In a high-risk population it is reasonable to diagnose tinea capitis using one or more cardinal symptoms. Oral griseofulvin at 20 to 25 mg/ kg/day with adjunctive shampooing for 6 weeks is moderately successful as treatment.

Safety and efficacy of terbinafine in a pediatric Iranian cohort of patients with Tinea capitis

BACKGROUND AND OBJECTIVES

Tinea capitis is a common infection of the scalp and hair shaft caused by dermatophyte fungi that mainly affects prepubescent children. Systemic therapy is required for treatment and to prevent spread. The aim of present study was to assess the effect of terbinafine for Tinea capitis treatment in children.

METHODS

Thirty Iranian pediatric patients with a clinical diagnosis of Tinea capitis were enrolled in the study. The Study was conducted in a general and referral teaching hospital (Imam Medical Centre - Tehran, Iran) from 2006 to 2007. Eligible patients with less than 20 kg of body weight were given 62.5 mg terbinafine, and for patients between 20 and 40 kg the dose was 125 mg, on the first visit. All patients had the second clinical visit and second samples for microscopic study were taken. For each patient, direct mycology test (KOH test) and mycological culture were carried out before the study was started and after second, fourth, fifth, sixth and eighth weeks. Probable drug's adverse effects were also recorded.

RESULTS

Based on the results of mycological culture of patients' lesions, Microsporum canis and Trichophyton sheonlini were considered as major causes of Tinea capitis in these children. Out of 30 study patients, KOH test of 93% in the 5th week and 100% in the 6th week was negative. All patients healed completely from signs of infection, after six weeks. Also, no severe side effects were seen in any patients.

CONCLUSION

According to the results of this study, the use of terbinafine is an effective therapy in Iranian cases of Tinea capitis in children without severe side effects.

Update on terbinafine with a focus on dermatophytoses

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

A randomized controlled trial assessing the efficacy of fluconazole in the treatment of pediatric tinea capitis

BACKGROUND

Griseofulvin is considered first-line therapy for tinea capitis, and the Physician's Desk Reference currently recommends 11 mg/kg per day microsize formulation for use in children. Diverse selective pressures have resulted in waning clinical efficacy of griseofulvin, such that higher doses and longer courses of treatment are required. These events have prompted the search for therapeutic alternatives. Fluconazole is one such treatment option, and a variety of studies using this drug have shown promise in the treatment of pediatric tinea capitis.

OBJECTIVE

We sought to assess the efficacy, safety, and optimal dose and duration of fluconazole therapy compared with standard-dose griseofulvin (11 mg/kg per day microsize formulation) in the treatment of pediatric tinea capitis.

METHODS

This randomized, multicenter, third-party-blind, 3-arm trial was designed as a superiority study to identify a therapeutically superior agent/regimen from the 3 treatment arms: (1) fluconazole 6 mg/kg per day for 3 weeks followed by 3 weeks of placebo, (2) fluconazole 6 mg/kg per day for 6 weeks, and (3) griseofulvin 11 mg/kg per day for 6 weeks. Efficacy variables included mycological, clinical, and combined outcomes. The primary efficacy variable was the combined outcome of the modified intent-to-treat population at week 6. Patient safety was assessed throughout the study. Statistical analysis of the efficacy variables was conducted by means of the Cochran-Mantel-Haenszel test.

RESULTS

At the end of treatment, mycological cures were present in 44.5%, 49.6%, and 52.2% of the fluconazole 3-week, fluconazole 6-week, and griseofulvin groups, respectively. Analysis of the primary efficacy variable failed to identify any superior agent, and differences between the combined outcomes of the fluconazole 6-week and griseofulvin groups at week 6 were not significant (P = .32). Regarding mycological, clinical, and combined outcomes, no significant differences between the fluconazole 6-week and griseofulvin groups were detected at any time point in the study. No new safety concerns were raised by this trial, and the incidence of treatment-related adverse events noted in this study is concordant with previous reports. Patients in the fluconazole arms of the study fared similarly. At the end of the trial, the difference in mycological cures between the fluconazole arms was only 7.5%, and increases in the incidence of certain treatment-related adverse events were observed in the fluconazole 6-week group.

LIMITATIONS

Adjunctive topical therapies and the impact of infected contacts were not assessed in this trial.

CONCLUSION

Systemic therapy with fluconazole 6 mg/kg per day and standard-dose griseofulvin produces comparable but low mycological and clinical cure rates. The limited efficacy of standard-dose griseofulvin and the lack of consensus regarding dose and duration of griseofulvin therapy in tinea capitis emphasize the need for controlled trials to identify optimal treatment parameters. Although the efficacy of fluconazole is no better than that of standard-dose griseofulvin, it may still be useful in select patients with a contraindication or intolerance to high-dose griseofulvin. The outcomes observed in this trial highlight the need to more clearly define the relative importance of adjunctive topical therapies and the evaluation and treatment of infected contacts as factors affecting cure rates.

Pharmacokinetics of terbinafine in young children treated for tinea capitis

BACKGROUND

Dermatophytes are the most common cause of human fungal infections. Response rates to existing therapy are lower than optimal, but newer agents like terbinafine hold promise for improved management of such infections. This investigation was designed to evaluate the single dose and steady state pharmacokinetics of terbinafine in young children with tinea capitis.

METHODS

Twenty-two otherwise healthy children (4-8 years) with tinea capitis were eligible for enrollment. Children were treated with terbinafine once daily according to body weight (<25 kg, 125 mg; 25-35 kg, 187.5 mg), and pharmacokinetic sampling was conducted after the first dose, at the midpoint of treatment and at steady state. Plasma terbinafine concentrations were quantitated, and the pharmacokinetic indices compared with adult data.

RESULTS

Absolute estimates of Cmax and area under the concentration curve (AUC)0-24 were comparable between children and adults for the administered dose; however, children demonstrated significantly lower estimates of exposure when dose was corrected for weight (Cmax SS 200 +/- 104 versus 454 +/- 185 ng/mL per mg/kg dose, P < 0.01; AUCSS: 1110 +/- 640 versus 2756 +/- 1775 ng*h/mL per mg/kg dose, P < 0.01). When examined along a continuum, age accounted for approximately 50% of the variability observed in dose-normalized Cmax and AUC (P < 0.01). A slight but significant reduction in apparent oral clearance was observed with increasing age (0.02 L/h/kg per yr) that likely accounts for the lesser degree of accumulation observed in children at steady state (accumulation ratio, 1.5 +/- 0.8 versus 2.3 +/- 0.6, P < 0.01). Adverse events consisted principally of headache (n = 3) and gastrointestinal complaints (altered eating habits n = 3, loss of appetite n = 3, stomachache n = 4, diarrhea n = 2). A reduction in neutrophil count was observed in 5 children and thought to be related to study drug in 2.

CONCLUSIONS

Children require significantly larger weight-normalized doses to approximate the exposure estimates observed in adults. The dosing scheme used in this investigation results in absolute exposure estimates at steady state and a safety profile that are not appreciably different from adults.

Tinea capitis mimicking dissecting cellulitis: a distinct variant

BACKGROUND

Tinea capitis is a common scalp dermatosis with several clinical patterns. Only two patients with a presentation of tinea capitis mimicking dissecting cellulitis have been described in the English literature.

OBSERVATION

We report a patient with tinea capitis mimicking dissecting cellulitis who did not respond to griseofulvin therapy at 16 mg/kg/day but eventually cleared after a protracted course of higher dose griseofulvin.

CONCLUSION

recognition of a dissecting cellulitis-like pattern of tinea capitis will increase clinical suspicion and avoid inappropriate management of a recalcitrant "dissecting cellulitis" in favor of prompt antifungal therapy of appropriate dosage and duration for patients with this unusual variant of tinea capitis.

Trichophyton rubrum tinea capitis in a young child

While the primary etiologic agent of tinea capitis in the United States has varied over the past century, the last several decades have been marked by a predominance of infection with Trichophyton tonsurans. Related anthropophilic organisms commonly isolated in other dermatophytoses are infrequently observed in tinea capitis. We report the unusual occurrence of tinea capitis in a young boy infected with Trichophyton rubrum.

Tinea capitis: epidemiology, diagnosis and management strategies

Tinea capitis is a common superficial fungal infection of the scalp in children, particularly in those of African descent. Trichophyton tonsuran, an anthropophilic dermatophyte, is responsible for the majority of cases in North America. The clinical presentations are variable and include: (i) a "seborrheic" form that is scaling, often without noticeable hair loss; (ii) a pustular, crusted pattern, either localized or more diffuse; (iii) a "black dot" variety characterized by small black dots within areas of alopecia; (iv) a kerion, which is an inflammatory mass; and (v) a scaly, annular patch. Most experts still consider griseofulvin to be the drug of choice, but recommend a higher dosage of 20-25 mg/kg/day for 8 weeks because of the increase in treatment failures. Despite a history of having an excellent tolerability profile, the long treatment course and higher doses required for griseofulvin have led to consideration of new antifungal agents for this infection. Terbinafine, itraconazole, and fluconazole compartmentalize in skin, hair, and nails, thereby allowing shorter treatment courses of < or =4 weeks. All have generally been shown to be effective in the treatment of tinea capitis and appear relatively well tolerated, with gastrointestinal symptoms being the most common adverse effect. Monitoring for liver enzyme elevations is generally unnecessary if therapy is limited to </=4 weeks. As more data regarding efficacy, tolerability, and dose administration becomes available, one or more of these new antifungal agents may become first-line therapy for tinea capitis. For now, we recommend their use in cases of treatment failure or recurrent noncompliance. Our personal preference in the younger child is fluconazole. It has a favorable tolerability profile and is available in liquid form. In the older child who can take a tablet, terbinafine is recommended. More data is available on this drug in the treatment of tinea capitis than the other two, and it is the least expensive. Although the oral antifungal agents are the most important aspect of therapy, adjunctive therapy may be beneficial. Sporicidal shampoos, such as selenium sulfide, can aid in removing adherent scales and hasten the eradication of viable spores from the scalp in the hope of decreasing the spread of this infection. The use of corticosteroids for the treatment of kerions is controversial. Many of the studies have design flaws or show variable results. We recommend either a short burst of oral corticosteroids or topical corticosteroids in patients with the most severe disease.

Terbinafine in the treatment of Trichophyton tinea capitis: a randomized, double-blind, parallel-group, duration-finding study

OBJECTIVES

Terbinafine has been shown to be effective in tinea capitis, using different treatment durations. However, no direct comparison of treatment duration has previously been investigated. This randomized, double-blind, parallel-group, multicenter study was designed to assess the effect of terbinafine treatment duration on the outcome of Trichophyton tinea capitis in a North American population.

METHODS

A total of 176 patients with a clinical diagnosis of tinea capitis were enrolled in this study and treated with oral terbinafine (3-6 mg/kg/d) for 1, 2, or 4 weeks. All patients were to be followed until week 12. A total of 159 patients had culture-confirmed tinea capitis attributable to Trichophyton species and constituted the intent-to-treat population used for efficacy analysis (50, 55, and 54 patients in the 1-, 2-, and 4-week arms, respectively).

RESULTS

At the end of study, effective treatment, defined as negative culture and low scores on signs and symptoms, was achieved in 56%, 69%, and 65% of patients who were treated with terbinafine for 1, 2, and 4 weeks, respectively. A negative culture was achieved in 60%, 76%, and 72%, respectively. Overall, the efficacy data showed that both the 2- and 4-week treatment regimens are clinically superior to the 1-week regimen. Terbinafine was well tolerated, and the incidence of adverse events showed no relationship to the duration of therapy.

CONCLUSION

When efficacy, cost, and compliance are taken into consideration, 2 weeks of terbinafine therapy appears to be the optimal treatment duration for patients with Trichophyton tonsurans tinea capitis.

Tinea capitis update: a continuing conflict with an old adversary

Infection with tinea capitis in childhood is a common, age-old problem that continues to plague patients and their families. As is true for most infectious diseases, the epidemiology of tinea capitis is in a constant state of flux and varies considerably with respect to geography and specific patient populations. Trichophyton tonsurans is now the most common cause of tinea capitis in the United States. A recent epidemiologic observation is a striking increase in the incidence of tinea capitis, particularly among African-Americans. Clinical studies over the past decade that have investigated the response of tinea capitis to griseofulvin, the mainstay treatment for this condition, suggest a decrease in sensitivity to this pharmacologic agent, in association with this new epidemiology. Important advances in the diagnosis and treatment of tinea capitis include a renewed interest in the use of the cotton swab method of diagnosing fungal cultures in children, and the ongoing investigation of promising new medications for the treatment of tinea capitis, including terbinafine, itraconazole, and fluconazole in this era of resistant organisms.

Tinea capitis

Tinea capitis is a common dermatophyte infection of the scalp in children. Dermatophytes are classified into three genera; tinea capitis is caused predominantly by Trichophyton or Microsporum species. On the basis of host preference and natural habitat, dermatophytes are also classified as anthropophilic, geophilic and zoophilic. The etiological agents of tinea capitis usually fall in the first and last categories. In North America, tinea capitis is now predominantly due to Trichophyton tonsurans. During the past 100 years the most common North American organism for tinea capitis was initially Microsporum canis followed later by M. audouinii. In other parts of the world the epidemiology varies. Tinea capitis is generally observed in children over the age of 6 years and before puberty, with African Americans being the most affected group. Clinical presentations are seborrheic-like scale, 'black dot' pattern, inflammatory tinea capitis with kerion and tiny pustules in the scalp. The clinical diagnosis should be confirmed by mycological examination. Wood's light examination was of value in diagnosing tinea capitis due to M. canis and M. audouinii; however, it is not helpful in T. tonsurans tinea capitis. Asymptomatic carriers may be a significant reservoir of infection and spread of spores may also involve inanimate objects. Carriers may benefit from shampooing their hair. Treatment of tinea capitis requires an oral antifungal agent. The data from the use of terbinafine, itraconazole and fluconazole are promising and suggest that these agents have an efficacy similar to griseofulvin while shortening the duration of therapy. Both griseofulvin and the newer antimycotics have a favorable adverse-effect profile and are associated with high compliance.

Oral griseofulvin remains the treatment of choice for tinea capitis in children

Tinea capitis is one of the most common infections of children. The standard treatment is griseofulvin. Itraconazole and terbinafine have in large part replaced griseofulvin in the treatment of onychomycosis and, in addition to fluconazole and ketoconazole, are evolving treatments for tinea capitis. The purpose of this review is to compare the efficacy, safety, and cost of oral antifungal agents for tinea capitis. Small, open-label studies of itraconazole, terbinafine, and fluconazole have reported encouraging results, suggesting that these drugs may be effective alternatives to griseofulvin; however, in large controlled studies griseofulvin continues to exhibit greater or equal efficacy. Ketoconazole appears to be the least efficacious. All five drugs appear relatively safe, however, only griseofulvin has a long track record of safety, is Food and Drug Administration (FDA) approved for the treatment of tinea capitis in children, and has the least known drug interactions. Fluconazole is FDA approved for use in children more than 6 months of age, yet not for the treatment of tinea capitis. Oral griseofulvin and terbinafine tablets are the least expensive of the antifungal agents; griseofulvin suspension is, however, more expensive than fluconazole suspension. For the combined reasons of efficacy, safety, and cost, and a long track record of use, we feel oral griseofulvin is still the present treatment of choice for tinea capitis. Newer antifungals are currently under investigation, and their role in treating tinea capitis in children is still being defined.

Tinea capitis: a current perspective

During the past 50 years, the predominant etiologic agent of tinea capitis in the United States and in Western Europe has changed from Microsporum audouinii to Trichophyton tonsurans. This is thought to be due in part to the sensitivity of M audouinii to griseofulvin treatment and, in part, due to the importing of T tonsurans by people emigrating from geographic areas where that vector had been the prominent cause of tinea capitis. With these changes, prospects for newer therapies with the novel antimycotic agents itraconazole, fluconazole, and terbinafine are reviewed. (J Am Acad Dermatol 2000;42:1-20.)

LEARNING OBJECTIVE

At the conclusion of this learning activity, participants should be familiar with the history, epidemiology, and current knowledge of tinea capitis, as well as the newer antifungal agents (ie, itraconazole, fluconazole, and terbinafine) to treat this infection.

The evolving role of itraconazole, fluconazole and terbinafine in the treatment of tinea capitis

Tinea capitis has become an increasing public health concern in the last decade. The increased incidence of the disease; its sometimes subtle, nonspecific clinical presentation; and the development of tolerance to griseofulvin therapy have led to the need for alternative safe, efficacious, inexpensive therapies that work rapidly. Itraconazole, fluconazole and terbinafine all possess pharmacologic and pharmacokinetic characteristics that theoretically would make them ideal therapies for tinea capitis. However, few randomized double blind controlled studies using these agents have been published. Thus far none have been conducted in the United States. The best available data support the utility and safety of the new antifungals in the treatment of tinea capitis. However, one must keep in mind that they are not yet approved by the Food and Drug Administration for this indication. Safety and cost considerations favor terbinafine for the treatment of T. tonsurans infections. M. canis infections may respond better to itraconazole, but good controlled studies to confirm this speculation have not been conducted. Short course and pulse dosing are particularly exciting options that may decrease cost and lower the risk of adverse side effects. Further useful information will hopefully come from future randomized double blind studies that will include patients from the United States. Studies using standardized definitions of disease, cure and appropriate follow-up evaluation of clinical and mycologic cure will best identify the optimal therapy for pediatric tinea capitis infections. The new systemic antifungals may provide more therapeutic options for fungal infections of the scalp. Note added in proof A recent trial comparing short course terbinafine and intraconazole therapy demonstrated that 2-week therapy with either drug provided good results and high cure rates (Jahangir M, et al. Br J Dermatol 1998;139:672-4).

Efficacy of itraconazole in children with Trichophyton tonsurans tinea capitis

BACKGROUND

Tinea capitis is prevalent in children. Although widely used as the drug of choice, the response to griseofulvin may be incomplete and an extended duration of therapy is often required. The response to newer antifungals has not been methodically evaluated in children with Trichophyton tonsurans infection.

OBJECTIVE

Our purpose was to determine the efficacy of itraconazole in children with tinea capitis caused by T. tonsurans.

METHODS

Pediatric patients with culture proven tinea capitis were enrolled from a hospital-based primary care clinic between January and December of 1996. Patients were treated with itraconazole 100 mg/day and a selenium sulfide-containing shampoo for 4 weeks. Children were evaluated mycologically and clinically every 2 weeks for 2 months. Patients were considered successfully treated if they were culture negative and clinically improved at the end of the study period. Children who remained culture positive or who were clinically not improved at 2 months were classified as treatment failures and retreated.

RESULTS

Twenty-five patients completed the study, and 10 (40%) were successfully treated. Fifteen children required re-treatment: 14 remained culture positive at week 8, and one was mycologically negative but clinically worse.

CONCLUSION

Itraconazole at a dose of 100 mg/day for 4 weeks may be effective in less than half of children with T. tonsurans tinea capitis.

Accumulation of fluconazole in scalp hair

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

Oral terbinafine: a new antifungal agent

OBJECTIVE

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

DATA SOURCES

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

DATA EXTRACTION

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

DATA SYNTHESIS

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

CONCLUSIONS

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