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PubMed2001

[Treatment of tinea unguium with terbinafine: an open study comparing twelve weeks and twenty-four weeks of continuous terbinafine therapy, and determination of terbinafine level in the target nails].

The study protocol was approved by the Ethical Committee of Sakai Municipal Hospital. A total of 40 outpatients with tinea unguium of the toenails, fingernails or both took part after giving voluntary written informed consent. Inclusion criteria were suggestive clinical appearance, a positive KOH preparation and an opaqueness of more than 50% of the nail length. The patients received 125 mg terbinafine once a day. The medication was taken after the evening meal and treatment was continued for 12 weeks. Medication stopped in twenty patients who responded well and a follow-up study was continued for 64 weeks. In the other 20 patients, medication was continued for 24 weeks and the follow-up study continued for 64 weeks. At 4-week intervals, the patients were evaluated for their clinical and mycological statuses and adverse reactions. Clipping of distal nail samples, including any attached subungual tissue, was done using nail clippers at 4-week intervals after cessation of therapy and the level of terbinafine was measured in the laboratory. No adverse reactions were detected. Tinea unguium of fingernails (1) and the third toes (2) were cured easily in the short term in the 12 week therapy group. One case in the 24 week therapy group was excluded because systemic steroid therapy was started for bullous pemphigoid at 32 weeks. The results of treatment of big toe onychomycosis were compared between the 12 week (17) and the 24 week (19). In the former group, 9 (52.9%) showed complete cure and 8 (47.1%) showed relapse or worse after cessation of therapy was. In 24 week therapy group, complete cure was achieved in 14 (73.7%) and relapse or worse in 5 (26.3%). The cure rate between the 2 groups was statistically not significant. Terbinafine was detected in the target nails up to 24 weeks after cessation of medication in both groups. Onychomycosis or tinea pedis reappeared in a few cases 12 to 16 weeks after medication ceased in the 12 week group. Topical antimycological therapy is necessary after cessation of oral terbinafine.

Administration, Oral↗
PubMed1996

Treatment of dermatophyte nail infections: an open randomized study comparing intermittent terbinafine therapy with continuous terbinafine treatment and intermittent itraconazole therapy.

BACKGROUND: terbinafine persists in the nail at effective concentrations for several weeks after discontinuation of treatment. OBJECTIVE: Our purpose was to verify whether intermittent terbinafine therapy is effective in dermatophytic onychomycosis and to compare the results of intermittent terbinafine with those of intermittent itraconazole and continuous terbinafine treatment. METHODS: An open, randomized study of 63 patients was performed with three treatment regimens: terbinafine, 250 mg daily (21 patients); terbinafine, 500 mg daily for 1 week every month (21 patients); or itraconazole, 400 mg daily for 1 week every month (21 patients). Treatment was continued for 4 months in toenail infections (60 patients) and 2 months in fingernail infections (3 patients). RESULTS: At the end of the follow-up period (6 months after discontinuation of treatment) 16 of the 17 patients (94.1%) with toenail onychomycosis were mycologically cured in the terbinafine 250 mg group, 16 of 20 (80%) in the terbinafine 500 mg group, and 15 of 20 (75%) in the itraconazole group. CONCLUSION: The percentage of patients who were mycologically cured was higher in the continuous terbinafine group than in the intermittent terbinafine and itraconazole groups, but statistical analysis did not reveal any significant difference between these cure rates.

Administration, Oral↗
PubMed2004

Combination therapy consisting of week pulses of oral terbinafine plus topical application of terbinafine cream in the treatment of onychomycosis.

BACKGROUND: Terbinafine, based on its pharmacokinetic properties, is a good candidate for pulse therapy. There are, as yet, no current guidelines for a terbinafine 1-week pulse regimine. OBJECTIVE: To determine the optimal 1-week pulse dosing regimen for combination therapy of oral terbinafine with complementary 1% terbinafine cream for the treatment of onychomycosis. DESIGN: A total of 69 onychomycosis patients received 250 mg terbinafine, given orally once daily for 7 days as 1-week pulses, separated by intervals of 2-3 weeks, until the desired improvement was observed. A daily application of 1% terbinafine cream was advised through to the evaluation date at 12 months follow-up. The treatment regimens were compared based on the number of pulses and the duration of treatment. RESULTS: The 45 patients (65.2%) who achieved complete cure received an average of 7.8+/-3.5 pulse treatments over 4.8+/-2.6 months. The optimal terbinafine dosing regimen consisted of alternate 1-week pulses, with most patients on this regimen (19/20 cases; 95%) achieving total cure. CONCLUSION: Favorable treatment outcome was gained from this terbinafine 1-week pulse regimen and also better compliance compared with a standard daily regimen.

Administration, Oral↗
PubMed2000

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.

Adult↗
PubMed2005

Combination of oral terbinafine and topical ciclopirox compared to oral terbinafine for the treatment of onychomycosis.

BACKGROUND: Treatment of onychomycosis has recently been enhanced by the introduction of combination therapies. OBJECTIVE: To evaluate the efficacy of a combination therapy of ciclopirox nail lacquer and oral terbinafine compared to oral terbinafine monotherapy for the treatment of onychomycosis caused by dermatophytes. PATIENTS AND METHODS: Eighty patients with onychomycosis were randomly assigned to receive either oral terbinafine 250 mg/day for 16 weeks or a combination of oral terbinafine 250 mg/day for 16 weeks and topical ciclopirox nail lacquer once daily for 9 months. Both groups were followed up for 9 months from start of treatment. RESULTS: After 9 months of treatment, the mycological cure rates were 22/34 (64.7%) for the terbinafine-only group and 30/34 (88.2%) for the combination therapy group (p<0.05). No significant difference was noted in the complete cure rate. CONCLUSION: Combination therapy of oral terbinafine and ciclopirox nail lacquer is a safe and more effective treatment for onychomycosis than terbinafine alone, especially in younger patients and in shorter-duration onychomycosis.

Administration, Oral↗
PubMed1994

Levels of terbinafine in plasma, stratum corneum, dermis-epidermis (without stratum corneum), sebum, hair and nails during and after 250 mg terbinafine orally once daily for 7 and 14 days.

In earlier skin pharmacokinetic studies we have shown that terbinafine is rapidly delivered to the stratum corneum, nails and hair both through sebum and by direct diffusion through dermis-epidermis. In the present study the skin pharmacokinetic profile of terbinafine was studied in two groups of eight human male volunteers during and after 250 mg orally once daily for 7 and 14 days. In the 7-day study high terbinafine levels were found in sebum (19.0 micrograms/g) and stratum corneum (2.5 micrograms/g), and a concentration in stratum corneum above the minimal inhibitory concentration for most dermatophytes was still found 48 days after the last day of medication. Terbinafine was found in peripheral nail clippings after 7 days of medication and the concentration was, in the 7-day study, 0.5 microgram/g 1 day after stopping medication; it was still 0.2 microgram/g 90 days after stopping treatment. The results in the 14-day study were in parallel with, but higher than, in the 7-day study. The elimination of terbinafine from several compartments is biphasic, with a faster initial elimination followed by a slower secondary elimination. For nails, the elimination is slower compared with the other compartments. The results indicate that terbinafine may be effective in short-term treatment of several dermatophytoses. The concentration of 0.2 microgram/g of terbinafine found in nails 90 days after stopping medication, following 7 days of treatment, indicates that the duration of therapy, even in tinea ungium, may be shorter than is currently the case.

Administration, Oral↗
PubMed2001

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.

Adult↗
PubMed2006

Combination of pulse therapy with terbinafine tablets and topical terbinafine cream for the treatment of dermatophyte onychomycosis: a pilot study.

We performed a pilot study to assess the safety and efficacy of pulse therapy with terbinafine tablets in 66 patients with dermatophyte onychomycosis. One pulse consisted of oral terbinafine tablets (500 mg/day) given for 1 week followed by a 3-week interval. Topical 1% terbinafine cream was applied daily. The number of pulses was determined by the extent of improvement in the affected nails and by the patient's requests, up to a maximum of six pulses. Efficacy was assessed based on both clinical and mycological examinations 1 year after treatment initiation. We observed a complete cure in 51 patients (77.3%), marked improvement in five patients (7.6%), improvement in five patients (7.6%) and slight improvement in one patient (1.5%). Four patients (6.0%) showed no change. In the patients who were completely cured, the average number of pulses used was 3.7 +/- 1.4 pulses and the treatment duration was 3.3 +/- 1.6 months. Nine patients experienced adverse effects, consisting of gastrointestinal disturbance (eight patients) and drug-induced eruption (one patient). There were no abnormal findings in the laboratory tests, including liver function tests. In summary, terbinafine pulse therapy in combination with topical application of terbinafine cream appeared safe and effective in this pilot study.

Administration, Cutaneous↗
PubMed2001

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.

Aldehydes↗
PubMed1993

Levels of terbinafine in plasma, stratum corneum, dermis-epidermis (without stratum corneum), sebum, hair and nails during and after 250 mg terbinafine orally once per day for four weeks.

The distribution of terbinafine in stratum corneum dermis-epidermis (without stratum corneum), sebum, hair, nails and plasma was studied in human male volunteers during and after 250 mg orally once daily for 28 days. The highest concentration was seen in sebum, 56.07 micrograms/g, after 14 days of therapy. The concentration was still 1.0 microgram/g 44 days after stop of medication. In stratum corneum the highest concentration, 14.4 micrograms/g, was seen 1 day after the last day of therapy, and it was 2.1 micrograms/g 44 days after stop of medication. The concentrations in hair and nails were lower with a maximum of 2.36 and 0.39 micrograms/g respectively, 1 day after stop of therapy, and still 0.21 microgram/g in hair and 0.09 microgram/g in nails 55 days after the last day of medication. With the exception of nails, all other tissue levels were at all times above the plasma concentrations. For nails, tissue levels exceeded that of plasma as early as 1 day after stop of medication, and this difference continued to increase until the last day of tissue sampling, 55 days after the last tablet. These results indicate that terbinafine is delivered to the stratum corneum through sebum and to a minor extent by direct diffusion through dermis-epidermis. Probably short-term therapy with terbinafine may be effective in the treatment of several dermatomycoses, due to the strong binding of terbinafine to stratum corneum for a long time after stop of medication.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1992

Clinical relevance of the antibacterial activity of terbinafine: a contralateral comparison between 1% terbinafine cream and 0.1% gentamicin sulphate cream in pyoderma.

The antibacterial efficacy of 1% terbinafine cream and 0.1% gentamicin sulphate cream was evaluated in 33 patients with superficial staphylococcal pyoderma in a double-blind contralateral comparison. After 12 days of active treatment, Staphylococcus aureus could be grown from only one out of 33 patients using terbinafine vs no patient using gentamicin. At the end of the study, a marked improvement in clinical symptoms was observed with no significant difference between the two therapies. Despite reviewing the patients three times during the course of the study, no adverse events were reported. The results of this study demonstrate that terbinafine has clinically relevant antibacterial properties which may be useful not only in pyoderma, but also in mixed fungal/bacterial infections, such as athlete's foot.

Adolescent↗
PubMed2003

Terbinafine: a review of its use in onychomycosis in adults.

UNLABELLED: Terbinafine, an orally and topically active antimycotic agent, inhibits the biosynthesis of the principal sterol in fungi, ergosterol, at the level of squalene epoxidase. Squalene epoxidase inhibition results in ergosterol-depleted fungal cell membranes (fungistatic effect) and the toxic accumulation of intracellular squalene (fungicidal effect). Terbinafine has demonstrated excellent fungicidal activity against the dermatophytes and variable activity against yeasts and non-dermatophyte molds in vitro. Following oral administration, terbinafine is rapidly absorbed and widely distributed to body tissues including the poorly perfused nail matrix. Nail terbinafine concentrations are detected within 1 week after starting therapy and persist for at least 30 weeks after the completion of treatment. Randomized, double-blind trials showed oral terbinafine 250 mg/day for 12 or 16 weeks was more efficacious than itraconazole, fluconazole and griseofulvin in dermatophyte onychomycosis of the toenails. In particular, at 72 weeks' follow-up, the multicenter, multinational, L.I.ON. (Lamisil vs Itraconazole in ONychomycosis) study found that mycologic cure rates (76 vs 38% of patients after 12 weeks' treatment; 81 vs 49% of recipients after 16 weeks' therapy) and complete cure rates were approximately twice as high after terbinafine treatment than after itraconazole (3 or 4 cycles of 400 mg/day for 1 week repeated every 4 weeks) in patients with toenail mycosis. Furthermore, the L.I.ON. Icelandic Extension study demonstrated that terbinafine was more clinically effective than intermittent itraconazole to a statistically significant extent at 5-year follow-up. Terbinafine produced a superior complete cure rate (35 vs 14%), mycologic cure rate (46 vs 13%) and clinical cure rate (42 vs 18%) to that of itraconazole. The mycologic and clinical relapse rates were 23% and 21% in the terbinafine group, respectively, compared with 53% and 48% in the itraconazole group. In comparative clinical trials, oral terbinafine had a better tolerability profile than griseofulvin and a comparable profile to that of itraconazole or fluconazole. Post marketing surveillance confirmed terbinafine's good tolerability profile. Adverse events were experienced by 10.5% of terbinafine recipients, with gastrointestinal complaints being the most common. Unlike the azoles, terbinafine has a low potential for drug-drug interactions. Most pharmacoeconomic evaluations have shown that the greater clinical effectiveness of oral terbinafine in dermatophyte onychomycosis translates into a cost-effectiveness ratio superior to that of itraconazole, fluconazole and griseofulvin. CONCLUSION: Oral terbinafine has demonstrated greater effectiveness than itraconazole, fluconazole and griseofulvin in randomized trials involving patients with onychomycosis caused by dermatophytes. The drug is generally well tolerated and has a low potential for drug interactions. Therefore, terbinafine is the treatment of choice for dermatophyte onychomycosis.

Antifungal Agents↗
PubMed1996

Safe coadministration of terbinafine and terfenadine: a placebo-controlled crossover study of pharmacokinetic and pharmacodynamic interactions in healthy volunteers.

The pharmacokinetic and pharmacodynamic interactions of terbinafine (Lamisil) and terfenadine (Seldane) were assessed in 26 healthy volunteers randomized to receive either terbinafine (250 mg tablet) or its placebo (terbinafine placebo), which were administered in a double-blind manner once daily for 18 days. On days 12 through 18, terfenadine was coadministered (60 mg twice daily, unblinded). Pharmacokinetic profiles were obtained for terbinafine and its desmethyl metabolite on day 11 (in the absence of terfenadine), day 12, and day 18. Terfenadine and terfenadine acid metabolite levels were also assayed on days 12 and 18. After a 4-week washout period, subjects were crossed over to the alternate treatment (terbinafine or terbinafine placebo). Pharmacodynamic measures were electrocardiographic (ECG) rhythm abnormalities, corrected QT interval (QTc), and plasma ALT levels. Terfenadine levels were evaluated; however, only eight of 1502 samples assayed were above the limit of quantitation. No effect of terbinafine administration on pharmacokinetic parameters for the terfenadine acid metabolite was observed, except for a decrease of approximately 20% in through terbinafine concentrations (C0hr; p < 0.05) on the last day of terfenadine plus terbinafine coadministration. Pharmacokinetic parameters for terbinafine were unchanged on the first day of terfenadine coadministration, and only small increases in area under the plasma concentration versus time curve from 0 to 24 hours and peak plasma concentrations (16.1%[p < 0.01] and 6.63% [p < 0.05]) were observed on the last day of terfenadine and terbinafine coadministration. Values for C0hr were also about 20% to 25% higher (p < 0.05). Steady-state levels of the terfenadine acid metabolite were achieved after 2 days of terfenadine coadministration, and steady-state levels of terbinafine and its desmethyl metabolite were achieved after 14 days of terbinafine administration. The incidence of ECG rhythm abnormalities was not significantly higher in any treatment group; however, the incidence of prolongation of QTc > 10% above baseline was significantly higher in the groups treated with terfenadine. No QTc prolongation occurred in the absence of terfenadine treatment. Both terbinafine and terfenadine were well tolerated when coadministered during this study, as indicated by the low incidence of complaints, abnormalities, and adverse events. The results of this study indicate that terbinafine and terfenadine can be safely coadministered.

Adult↗
PubMed1997

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.

Antifungal Agents↗
PubMed1994

Effect of terbinafine on the pharmacokinetics of cyclosporin in humans.

Cyclosporin is largely metabolized by hepatic cytochrome P450 enzymes, and azole drugs that inhibit cytochrome P450 may precipitate cyclosporin toxicity. The allylamine terbinafine binds to a small subfraction of hepatic cytochrome P450 in type I fashion, and has no effect upon hepatic metabolism of cyclosporin in vitro. The purpose of this study was to determine whether oral terbinafine alters the pharmacokinetics of oral cyclosporin in vivo. Twenty male volunteers (age 19-44 years), were randomly allocated to two groups. The first group received three single oral doses of cyclosporin 300 mg at intervals of 21 d. The second and third doses of cyclosporin were preceded by a 6-d course of oral terbinafine 250 mg each morning. A further 250 mg of terbinafine was taken with the second and third doses of cyclosporin. Blood levels of cyclosporin and terbinafine were monitored for 36 h after each dose. The second group received a 7-d course of terbinafine 250 mg each morning. On the seventh day a single dose of cyclosporin 300 mg was taken together with the terbinafine. Blood levels of both cyclosporin and terbinafine were monitored for 36 h. Two further single doses of cyclosporin 300 mg were given at intervals of 2 weeks and the cyclosporin levels again monitored. In both groups each cyclosporin dose was preceded by an 8-h fast. The mean peak blood concentration of cyclosporin when taken alone was 958 micrograms/l, and 822 when taken with terbinafine. The mean area under the curve for cyclosporin was 4207 micrograms/l/h when taken alone and 3665 when taken with terbinafine. The mean absorption half-life for cyclosporin when taken alone was 0.29 h, and 0.33 when taken with terbinafine. The mean time of maximum concentration and elimination half-life of cyclosporin were unaltered by terbinafine. The results suggest that terbinafine is likely to prove a safe systemic anti-fungal treatment for patients who are taking cyclosporin.

Absorption↗
PubMed2002

In-vitro distribution of terbinafine in rat and human blood.

The association of drugs with plasma lipoproteins has the potential to influence drug action and disposition. In this study, the uptake and distribution of the lipophilic antifungal drug, terbinafine, was investigated in rat and human blood and plasma. Fresh plasma was incubated with terbinafine (200-1000 ng mL(-1)), then subjected to vertical spin density gradient ultracentrifugation to separate protein fractions. The concentrations of terbinafine in each fraction was determined using a validated reversed-phase HPLC method. The association of terbinafine with very-low-density lipoproteins (15.5 +/- 7.1% of total concentration) in human plasma was significantly lower than that associated with fractions containing soluble proteins (28.0 +/- 6.2%), high- (26.8 +/- 7.7%) and low-density lipoproteins (31.6 +/- 4.6%). In rats terbinafine was found to be distributed evenly through plasma protein fractions. The association of terbinafine in lipoproteins was independent of concentration (over the range 200-1,000 ng mL(-1)) and species. The distribution of terbinafine was examined in human and rat blood and the blood-to-plasma ratio of terbinafine was 0.70+0.09 and 1.01 +/- 0.20, respectively, indicating higher association of terbinafine with plasma components than erythrocytes in humans. This study suggests that in humans and rats, terbinafine associates with a number of plasma proteins independently of terbinafine concentration. Alteration in plasma lipoprotein concentrations are therefore likely to influence terbinafine binding in blood and distribution in the body.

Animals↗
PubMed1998

Pharmacokinetics and pharmacology of terbinafine and itraconazole.

BACKGROUND: Two new systemic antifungal agents, terbinafine and itraconazole, have expanded the choices for treatment of onychomycosis. The pharmacokinetic and pharmacologic properties provide the basis of their activity and are related to their efficacy and safety in dermatophyte infections. OBJECTIVE: We describe the pharmacodynamics, pharmacokinetics, and pharmacology of terbinafine and itraconazole and the features that form a framework for comparing their efficacy. PHARMACODYNAMICS: Both terbinafine and itraconazole ultimately block ergosterol synthesis; terbinafine disrupts fungal cell wall synthesis earlier (squalene to squalene epoxide) than does itraconazole (lanosterol to ergosterol). In vitro, terbinafine exposure results in a toxic accumulation of squalene and decreased production of ergosterol. Minimal inhibitory concentrations (MICs) of terbinafine for dermatophytes are essentially equal to minimal fungicidal concentrations (MFCs). However, the MFCs of itraconazole are much higher than the MICs. PHARMACOLOGIC PROFILE: Both itraconazole and terbinafine penetrate keratinizing tissue; levels reached in nail plate exceed those in plasma. Therapeutic levels of the itraconazole persist in nails for up to 6 months after discontinuation of 3 months of therapy (200 mg/day) and during various pulsed cycles. After discontinuation of 1 month of therapy, terbinafine persists at therapeutic levels in the nail. Itraconazole has an affinity for mammalian cytochrome P-450 enzymes as well as for fungal P-450-dependent enzyme, and thus has the potential for clinically important interactions (e.g., astemizole, terfenadine, rifampin, oral contraceptives, H2 receptor antagonists, warfarin, cyclosporine). Terbinafine is not metabolized through this system and has little potential for drug-drug interactions. CONCLUSION: The low MFCs exhibited by terbinafine for dermatophytes may be important in its clinical efficacy and low relapse rates. The safety profile of terbinafine directly reflects its mechanism of action.

Antifungal Agents↗