Terbinafine: an update

Reversible agranulocytosis associated with oral terbinafine in a pediatric patient

We report a case of terbinafine-induced agranulocytosis in a pediatric patient. This effect was noted 4 weeks after starting terbinafine and resolved within 1 week without the institution of therapy with granulocyte colony-stimulating factor, a course similar to reports in adults. With the incidence of severe side effects still unclear in children, this case argues for continued blood surveillance during courses of terbinafine and for the confirmation of infection before initiation of the drug.

Terbinafine-induced subacute cutaneous lupus erythematosus

BACKGROUND

Recently, the induction of subacute cutaneous lupus erythematosus (SCLE) and exacerbation of systemic lupus erythematosus by terbinafine have been reported.

OBJECTIVE

We describe 4 cases of SCLE, one associated with chilblain lupus, which occurred during therapy with oral terbinafine for onychomycosis.

METHODS

Of 21 consecutive patients with SCLE attending the outpatient dermatology department at Muenster University clinic during a 1-year period, 4 patients with terbinafine-induced SCLE were seen. Patients were examined fully and photographed; histologic findings as well as serologic and follow-up data were evaluated.

RESULTS

In addition to high titers of antinuclear antibodies (ANA) with a homogeneous pattern, anti-Ro(SS-A) antibodies were present; in 3 of 4 women, anti-La(SS-B) antibodies were also found. All patients had anti-histone antibodies as in drug-induced lupus and showed the characteristic genetic association of SCLE with the HLA-B8,DR3 haplotype; moreover, in 2 cases, HLA-DR2 was also present. After discontinuation of terbinafine, ANA titers decreased; anti-histone antibodies also became undetectable within 4(1/2) months in 3 patients concomitant with subsidence of the SCLE eruption in all patients.

CONCLUSION

Terbinafine is a drug that appears to infrequently induce SCLE with high titers of ANAs and anti-histone antibodies in genetically susceptible persons.

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.

Association between terbinafine and arthralgia, fever and urticaria: symptoms or syndrome?

PURPOSE

The antifungal agent terbinafine has been approved for marketing in The Netherlands since 1992. Adverse drug reactions (ADRs) may occur in about 10% of the patients, the majority gastrointestinal disorders and skin reactions. Since the introduction of terbinafine, the Netherlands Pharmacovigilance Foundation Lareb received eight reports of arthralgia during the use of this drug. In four reports the additional presence of skin reactions was mentioned, two of these reports concerned urticaria. Two patients who reported arthralgia also had a fever. These reports were described in more detail, and analysed statistically in order to determine whether symptoms are interrelated.

METHODS

All reports with known gender and a reporting date between 1 March 1992 and 1 January 1999, concerning patients older than 10 years, were included. The extent to which the symptoms urticaria, fever and arthralgia were interrelated was examined by logistic regression modelling.

RESULTS

Case series as well as the results of the statistical analysis show a clustering of symptoms among reports of patients using terbinafine. Both urticaria and arthralgia were statistically significantly associated with reports on terbinafine compared to all other reports in the database.

CONCLUSION

The findings might point towards a clustering of these symptoms in patients using terbinafine. Possibly these symptoms have a shared aetiology, presumably an immunological reaction.

Identification of a reactive metabolite of terbinafine: insights into terbinafine-induced hepatotoxicity

Oral terbinafine treatment for superficial fungal infections of toe and fingernails is associated with a low incidence (1:45000) of hepatobiliary dysfunction. Due to the rare and unpredictable nature of this adverse drug reaction, the mechanism of toxicity has been hypothesized to be either an uncommon immunological or metabolically mediated effect. However, there is little evidence to support either mechanism, and toxic metabolites of terbinafine have not been identified. We incubated terbinafine with both rat and human liver microsomal protein in the presence of GSH and were able to trap an allylic aldehyde, 7,7-dimethylhept-2-ene-4-ynal (TBF-A), which corresponds to the N-dealkylation product of terbinafine. TBF-A was also prepared synthetically and reacted with excess GSH to yield conjugates with HPLC retention times and mass spectra identical to those generated in the microsomal incubations. The major GSH conjugate, characterized by (1)H NMR, corresponds to addition of GSH in a 1,6-Michael fashion. There remains a second electrophilic site on this metabolite, which can bind either to a second molecule of GSH or to cellular proteins via a 1,4-Michael addition mechanism. Moreover, we demonstrated that the formation of the GSH conjugates was reversible. We speculate that this allylic aldehyde metabolite, formed by liver enzymes and conjugated with GSH, would be transported across the canalicular membrane of hepatocytes and concentrated in the bile. The mono-GSH conjugate, which is still reactive, could bind to hepatobiliary proteins and lead to direct toxicity. Alternatively, it could modify canalicular proteins and lead to an immune-mediated reaction causing cholestatic dysfunction.

Clinical trial: the safety of terbinafine in patients over the age of 60 years: a multicenter trial in onychomycosis of the feet

Thirty patients completed this open-label, multicenter prospective study performed to evaluate the efficacy and safety of terbinafine treatment of onychomycosis of the feet in elderly patients. Inclusion criteria included an age of 60 years or older, a diagnosis of onychomycosis confirmed by positive potassium hydroxide (KOH) preparation at baseline, and toenails capable of regrowth. Patients were excluded from the study if they had received any systemic antifungal therapy within the previous 3 months or topical antifungal therapy within 1 week prior to the start of the study; had psoriasis; had toenail abnormalities interfering with normal toenail appearance; were immunosuppressed or immunodeficient; or had serum hepatic enzyme (serum glutamic-oxaloacetic transaminase, SGOT; serum glutamic-pyruvic transaminase, SGPT) values greater than 1.5 times the upper limit of normal at baseline. Following baseline evaluations, eligible patients received a 12-week supply of oral terbinafine (250 mg/day) for self-administration. Compliance was assessed by tablet counts at each visit and defined as the use of at least 80% of the medication prescribed at the first two visits. Follow-up evaluations were conducted for the next 60 weeks, for a total study period of 72 weeks. These visits occurred at weeks 6, 12, 24, 36, 48, and 72. All follow-up visits included: (i) the reporting of adverse effects; (ii) assessment of efficacy by KOH preparation, mycologic culture, and investigator evaluation; and (iii) physician and patient global assessments of various quality of life parameters (except for the visit at week 36). Safety and tolerance were assessed by physical examination at baseline and week 12, by laboratory evaluations (hematology, blood chemistry, and urinalysis) at baseline, week 6 and week 12, and by reporting and evaluation of adverse events throughout the entire study. Investigators assessed the extent of involvement of the target toenail and recorded global assessments of therapeutic efficacy at all visits. Mycologic evaluation was conducted by KOH preparation and a mycologic culture of the target toenail. Because of discrepancies in KOH results between the investigator sites and the central laboratory in early analyses, we chose to use the mycologic culture results to evaluate efficacy. Because all 30 subjects were treated with terbinafine, the entire group was considered for safety evaluation.

Current Management of Onychomycosis and Dermatomycoses

Three newer oral antifungal agents, itraconazole, terbinafine and fluconazole, have revolutionized treatment of superficial mycoses. The tissue pharmacokinetics of itraconazole and terbinafine allow much shorter courses of therapy- with higher efficacy-in the treatment of onychomycosis, compared to other oral agents. Itraconazole pulse dosing and terbinafine daily dosing have shown comparable efficacy against dermatophyte onychomycosis; similar itraconazole regimens have been effective against nondermatophyte infections. Refractory clinical patterns of nail disease appear to be more responsive to oral antifungal therapy when combined with adjunctive therapy, such as debridement. These agents are effective against cutaneous dermatophytosis, with shorter treatment regimens. Tinea versicolor may be treated with a single-dose, intermittent, or daily regimen of an oral azole agent, depending on the drug selected. These newer oral antifungal agents have been proven effective against tinea capitis; effective regimens are shorter than those for griseofulvin. The safety profile of these newer agents has been very favorable.

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.

Acute generalized exanthematous pustulosis associated with oral terbinafine

A case history of acute generalized exanthematous pustulosis (AGEP) following oral terbinafine is reported. A 64-year-old woman presented with a rapidly spreading micropustular eruption 3 days after completing a 28-day course of oral terbinafine. There was a positive family history of psoriasis but no personal history. The clinical presentation and histopathology were consistent with AGEP. There was nearly complete resolution of the pustular eruption within 3.5 weeks following cessation of oral terbinafine and treatment with topical and systemic corticosteroids. The patient has remained free of any recurrence 18 months later. A summary of drugs known to be associated with AGEP is presented. Prompt recognition of AGEP is stressed in order to avoid confusion with acute generalized pustular psoriasis or a systemic infection. The most important aspect of management is the immediate withdrawal of the suspect drug.

Onychomycosis. Treatment, quality of life, and economic issues

Onychomycosis is a public health concern because of its high worldwide incidence and prevalence, and its potential for spread of fungal elements to others, as well as complications such as cellulitis, bacterial infection, pain, and extensive dermatophytic infections. The incidence of onychomycosis has been increasing, particularly in individuals over 60 years of age, patients with HIV infection, and patients with diabetes mellitus. Onychomycosis may impact upon physical, functional, psychosocial, and emotional aspects of life. Difficulty walking, wearing shoes, and embarrassment are common complaints. Quantification of such quality-of-life changes are significant to clinical practice in that many factors can affect overall patient health. In light of the potential clinical implications on physical and mental health, onychomycosis should be considered a medical condition that deserves rigorous clinical management. Onychomycosis can be treated effectively and with comparative safety with the new generation of oral antifungal agents (itraconazole, fluconazole and terbinafine). Significantly improved pharmacokinetic and pharmacodynamic profiles permit markedly reduced duration of administration, individual drug exposure, and ultimately enhanced patient compliance and satisfaction with therapy. In addition, a number of pharmacoeconomic studies have documented the cost effectiveness of these newer agents compared with both traditional pharmacologic treatment and topical therapies. The currency figures quoted are 1997 values. With regard to continuous oral antifungal regimens, terbinafine therapy has been found to be most cost effective in the treatment of toenail onychomycosis, with a drug acquisition cost of $US522.50. However, improved safety, tolerability, efficacy and cost effectiveness have been documented with itraconazole intermittent, pulse regimens. With itraconazole pulse therapy, the drug acquisition cost decreases to $US488.90. Additionally, the total cost of medical management is less for itraconazole therapy compared with that of terbinafine ($US261.00 vs $US306.00). Because sensitivity analyses for itraconazole and terbinafine have been found to be somewhat comparable in terms of mycological cure, clinical response, and relapse rates, other variables such as safety and efficacy profiles, and patient attitudes and expectations toward therapy need to be considered when formulating an onychomycosis pharmacologic treatment plan. The drug aquisition cost of fluconazole given as a 300 mg dose once weekly for 6 months is $US562.76 and given as a 150 mg dose once weekly (for 6 months) $US281.38.

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.

Oral terbinafine (Lamisil) in the short-term treatment of fungal infections of the skin: results of a post-marketing surveillance study

Oral terbinafine (Lamisil, Novartis Pharma AG, Basel, Switzerland) is an effective therapy for fungal infections of the skin and nails. A post-marketing surveillance study was undertaken to evaluate the clinical efficacy and safety of oral terbinafine. A total of 454 patients with clinically and mycologically confirmed superficial fungal infections of the skin were enrolled from 79 dermatology clinics. Patients received oral terbinafine (250 mg day-1) for 2 weeks. Specific signs and symptoms were assessed by standard questionnaire before, immediately after, and 4 weeks after treatment. Observed improvements in patients after 2 weeks treatment were: erythema 81%, blistering 33%, exudation 50%, scaling 89%, pruritus 83%. After 4 weeks treatment, erythema was absent in 85% of patients, blistering and exudation in 99.7%, scaling in 82%, and pruritus in 94%. Overall clinical efficacy was assessed as good to excellent in 97% of patients. Adverse effects--mainly gastrointestinal and minor skin rashes--were reported in 5.3% of patients. The results of this study confirm that oral terbinafine is safe and highly effective for the short-term treatment of fungal skin infections.

An open study of tinea capitis in 50 children treated with a 2-week course of oral terbinafine

BACKGROUND

Terbinafine is used in the treatment of dermatophyte infections. There have been several studies suggesting a good response to terbinafine in treating tinea capitis, specifically with dermatophytes of the Trichophyton species.

METHODS

We enrolled 50 consecutive children with a clinical diagnosis of tinea capitis into an open study using terbinafine for 2 weeks.

RESULTS

Clinical and mycologic cure occurred in more than 86% of patients with no side effects and good compliance.

CONCLUSION

In this study terbinafine was a safe and effective treatment of tinea capitis in children, particularly when caused by the Trichophyton species.

Immunohistochemical study of type I collagen turn-over and of matrix metalloproteinases in chromoblastomycosis before and after treatment by terbinafine

The distribution of type I collagen, the major component of human dermis, was characterized by immunohistochemistry in skin lesions of chromoblastomycosis, a chronic cutaneous mycosis, before and after a specific antifungal treatment with terbinafine to study the changes induced in the lesions by the treatment. Newly synthesized type I collagen was studied with an antibody directed against the aminoterminal propeptide of the molecule (PINP), whereas mature, cross-linked type I collagen was detected with an antibody against the carboxyterminal telopeptide of type I collagen (ICTP). The isopeptide N epsilon gamma-glutamyl lysine (N epsilon gamma GL), synthesized by transglutaminase and able to cross-link several components of the extracellular matrix, has also been investigated with two monoclonal antibodies to determine if it is involved in the stabilisation of the fibrotic cutaneous lesions. The degradative process involved in the remodelling has also been assessed by immunohistochemistry with anti-metalloproteinase (MMP-1 and MMP-9) and anti-tissue inhibitor (TIMP-1) antibodies. All tissue macrophages stained for CD68 and MMP-9, but not for MMP-1, while the polymorphonuclear neutrophils had an elastase and a weak MMP-9 phenotype. The fibroblasts of fibrotic areas stained constantly for N epsilon gamma GL and PINP. The immunostaining of extracellular matrix for ICTP and N epsilon gamma GL, and the number of PINP-positive fibroblasts, decreased significantly after one year of antifungal treatment. Terbinafine treatment decreases the synthesis of type I collagen and leads to a partial reversal of the cutaneous fibrotic lesions, independently of the cure of the fungal infection.

Hypersensitivity syndrome reaction to oral terbinafine

Terbinafine is used extensively to treat onychomycosis and other dermatomycoses. The case of a patient who developed a hypersensitivity syndrome reaction to oral terbinafine is discussed. A 66-year-old male was placed on terbinafine (250 mg/day) for the treatment of onychomycosis. After 4.5 weeks of therapy, the patient developed a cutaneous eruption, pyrexia, lymph-adenopathy and hepatic dysfunction. No infectious or other cause was found for the symptoms and signs, which resolved within 6 weeks of stopping terbinafine. The patient had been on prednisone, doxazosin mesylate and aspirin for several months prior to starting terbinafine. These medications were continued during the episode and subsequently afterwards, with adjustment to the prednisone dosage only. The hypersensitivity syndrome reaction in this case involved multiple systems and was idiosyncratic in nature with no apparent predisposing factors. With the increasing use of oral terbinafine, it is likely that rare adverse events will occur more frequently. It is, therefore, important for physicians to be aware of the possible development of a hypersensitivity syndrome reaction in a patient on terbinafine who experiences an adverse event with multisystem involvement. Prompt recognition and determination of the extent of systemic involvement is important for the proper management of the patient.