Product Elements:
Terbinafine hydrochloride terbinafine hydrochloride terbinafine hydrochloride terbinafine silicon dioxide hypromellose, unspecified magnesium stearate microcrystalline cellulose sodium starch glycolate type a potato oblong b;526
Drug Interactions:
7. drug interactions terbinafine is an inhibitor of cyp450 2d6 isozyme and has an effect on metabolism of desipramine. drug interactions have also been noted with cimetidine, fluconazole, cyclosporine, rifampin, and caffeine. ( 7.1 ) 7.1 drug-drug interactions in vivo studies have shown that terbinafine is an inhibitor of the cyp450 2d6 isozyme. drugs predominantly metabolized by the cyp450 2d6 isozyme include the following drug classes: tricyclic antidepressants, selective serotonin reuptake inhibitors, beta-blockers, antiarrhythmics class 1c (e.g., flecainide and propafenone) and monoamine oxidase inhibitors type b. coadministration of terbinafine tablets should be done with careful monitoring and may require a reduction in dose of the 2d6-metabolized drug. in a study to assess the effects of terbinafine on desipramine in healthy volunteers characterized as normal metabolizers, the administration of terbinafine resulted in a 2-fold increase in c max and a 5-fold increase in area unde
Read more...r the curve (auc). in this study, these effects were shown to persist at the last observation at 4 weeks after discontinuation of terbinafine tablets. in studies in healthy subjects characterized as extensive metabolizers of dextromethorphan (antitussive drug and cyp2d6 probe substrate), terbinafine increases the dextromethorphan/ dextrorphan metabolite ratio in urine by 16- to 97-fold on average. thus, terbinafine may convert extensive cyp2d6 metabolizers to poor metabolizer status. in vitro studies with human liver microsomes showed that terbinafine does not inhibit the metabolism of tolbutamide, ethinylestradiol, ethoxycoumarin, cyclosporine, cisapride and fluvastatin. in vivo drug-drug interaction studies conducted in healthy volunteer subjects showed that terbinafine does not affect the clearance of antipyrine or digoxin. terbinafine decreases the clearance of caffeine by 19%. terbinafine increases the clearance of cyclosporine by 15%. the influence of terbinafine on the pharmacokinetics of fluconazole, cotrimoxazole (trimethoprim and sulfamethoxazole), zidovudine or theophylline was not considered to be clinically significant. coadministration of a single dose of fluconazole (100 mg) with a single dose of terbinafine resulted in a 52% and 69% increase in terbinafine c max and auc, respectively. fluconazole is an inhibitor of cyp2c9 and cyp3a enzymes. based on this finding, it is likely that other inhibitors of both cyp2c9 and cyp3a4 (e.g., ketoconazole, amiodarone) may also lead to a substantial increase in the systemic exposure (c max and auc) of terbinafine when concomitantly administered. there have been spontaneous reports of increase or decrease in prothrombin times in patients concomitantly taking oral terbinafine and warfarin, however, a causal relationship between terbinafine tablets and these changes has not been established. terbinafine clearance is increased 100% by rifampin, a cyp450 enzyme inducer, and decreased 33% by cimetidine, a cyp450 enzyme inhibitor. terbinafine clearance is unaffected by cyclosporine. there is no information available from adequate drug-drug interaction studies with the following classes of drugs: oral contraceptives, hormone replacement therapies, hypoglycemics, phenytoins, thiazide diuretics, and calcium channel blockers. 7.2 food interactions an evaluation of the effect of food on terbinafine tablets was conducted. an increase of less than 20% of the auc of terbinafine was observed when terbinafine tablets were administered with food. terbinafine tablets can be taken with or without food.
Indications and Usage:
1. indications and usage terbinafine tablets are indicated for the treatment of onychomycosis of the toenail or fingernail due to dermatophytes (tinea unguium). prior to initiating treatment, appropriate nail specimens for laboratory testing [potassium hydroxide (koh) preparation, fungal culture, or nail biopsy] should be obtained to confirm the diagnosis of onychomycosis. terbinafine tablets are an allylamine antifungal indicated for the treatment of onychomycosis of the toenail or fingernail due to dermatophytes (tinea unguium). ( 1 )
Warnings and Cautions:
5. warnings and precautions ⢠liver failure, sometimes leading to liver transplant or death, has occurred with the use of oral terbinafine. obtain pretreatment serum transaminases. prior to initiating treatment and periodically during therapy, assess liver function tests. discontinue terbinafine tablets if liver injury develops. ( 5.1 ) ⢠taste disturbance, including taste loss, has been reported with the use of terbinafine tablets. taste disturbance can be severe, may be prolonged, or may be permanent. discontinue terbinafine tablets if taste disturbance occurs. ( 5.2 ) ⢠smell disturbance, including loss of smell, has been reported with the use of terbinafine tablets. smell disturbance may be prolonged, or may be permanent. discontinue terbinafine tablets if smell disturbance occurs. ( 5.3 ) ⢠depressive symptoms have been reported with terbinafine use. prescribers should be alert to the development of depressive symptoms. ( 5.4 ) ⢠severe neutropenia has bee
Read more...n reported. if the neutrophil count is less than or equal to 1000 cells/mm 3 , terbinafine tablets should be discontinued. ( 5.5 ) ⢠stevens-johnson syndrome, toxic epidermal necrolysis, erythema multiforme, exfoliative dermatitis, bullous dermatitis, and drug reaction with eosinophilia and systemic symptoms (dress) syndrome have been reported with oral terbinafine use. if signs or symptoms of drug reaction occur, treatment with terbinafine tablets should be discontinued. ( 5.6 ) 5.1 hepatotoxicity terbinafine tablets are contraindicated for patients with chronic or active liver disease. before prescribing terbinafine tablets, perform liver function tests because hepatotoxicity may occur in patients with and without preexisting liver disease. cases of liver failure, some leading to liver transplant or death, have occurred with the use of terbinafine tablets in individuals with and without preexisting liver disease. in the majority of liver cases reported in association with use of terbinafine tablets, the patients had serious underlying systemic conditions. the severity of hepatic events and/or their outcome may be worse in patients with active or chronic liver disease. periodic monitoring of liver function tests is recommended. discontinue terbinafine tablets if biochemical or clinical evidence of liver injury develops. warn patients prescribed terbinafine tablets and/or their caregivers to report immediately to their healthcare providers any symptoms or signs of persistent nausea, anorexia, fatigue, vomiting, right upper abdominal pain or jaundice, dark urine, or pale stools. advise patients with these symptoms to discontinue taking oral terbinafine, and immediately evaluate the patient's liver function. 5.2 taste disturbance including loss of taste taste disturbance, including taste loss, has been reported with the use of terbinafine tablets. it can be severe enough to result in decreased food intake, weight loss, anxiety, and depressive symptoms. taste disturbance may resolve within several weeks after discontinuation of treatment, but may be prolonged (greater than 1 year), or may be permanent. if symptoms of a taste disturbance occur, terbinafine tablets should be discontinued. 5.3 smell disturbance including loss of smell smell disturbance, including loss of smell, has been reported with the use of terbinafine tablets. smell disturbance may resolve after discontinuation of treatment, but may be prolonged (greater than 1 year), or may be permanent. if symptoms of a smell disturbance occur, terbinafine tablets should be discontinued. 5.4 depressive symptoms depressive symptoms have occurred during postmarketing use of terbinafine tablets. prescribers should be alert to the development of depressive symptoms, and patients should be instructed to report depressive symptoms to their physician. 5.5 hematologic effects transient decreases in absolute lymphocyte counts (alcs) have been observed in controlled clinical trials. in placebo-controlled trials, 8/465 subjects receiving terbinafine tablets (1.7%) and 3/137 subjects receiving placebo (2.2%) had decreases in alc to below 1000/mm 3 on 2 or more occasions. in patients with known or suspected immunodeficiency, physicians should consider monitoring complete blood counts if treatment continues for more than 6 weeks. cases of severe neutropenia have been reported. these were reversible upon discontinuation of terbinafine tablets, with or without supportive therapy. if clinical signs and symptoms suggestive of secondary infection occur, a complete blood count should be obtained. if the neutrophil count is less than or equal to 1000 cells/mm 3 , terbinafine tablets should be discontinued and supportive management started. 5.6 serious skin/hypersensitivity reactions there have been postmarketing reports of serious skin/hypersensitivity reactions [e.g., stevens-johnson syndrome, toxic epidermal necrolysis, erythema multiforme, exfoliative dermatitis, bullous dermatitis, and drug reaction with eosinophilia and systemic symptoms (dress) syndrome]. manifestations of dress syndrome may include cutaneous reaction (such as rash or exfoliative dermatitis), eosinophilia, and one or more organ complications such as hepatitis, pneumonitis, nephritis, myocarditis, and pericarditis. if progressive skin rash or signs/symptoms of the above drug reactions occur, treatment with terbinafine tablets should be discontinued. 5.7 lupus erythematosus during postmarketing experience, precipitation and exacerbation of cutaneous and systemic lupus erythematosus have been reported in patients taking terbinafine tablets. terbinafine tablets should be discontinued in patients with clinical signs and symptoms suggestive of lupus erythematosus. 5.8 thrombotic microangiopathy cases of thrombotic microangiopathy (tma), including thrombotic thrombocytopenic purpura and hemolytic uremic syndrome, some fatal, have been reported with terbinafine. discontinue terbinafine if clinical symptoms and laboratory findings consistent with tma occur. the findings of unexplained thrombocytopenia and anemia should prompt further evaluation and consideration of diagnosis of tma.
Dosage and Administration:
2. dosage and administration ⢠prior to administering, evaluate patients for evidence of chronic or active liver disease. ( 2.1 ) ⢠fingernail onychomycosis: one 250 mg tablet, once daily for 6 weeks. ( 2.2 ) ⢠toenail onychomycosis: one 250 mg tablet, once daily for 12 weeks. ( 2.2 ) 2.1 assessment prior to initiation before administering terbinafine tablets, evaluate patients for evidence of chronic or active liver disease [see contraindications (4) and warnings and precautions (5.1) ] . 2.2 dosage fingernail onychomycosis: one 250 mg tablet once daily for 6 weeks. toenail onychomycosis: one 250 mg tablet once daily for 12 weeks. the optimal clinical effect is seen some months after mycological cure and cessation of treatment. this is related to the period required for outgrowth of healthy nail.
Dosage Forms and Strength:
3. dosage forms and strengths tablet, 250 mg, white, oblong, unscored, debossed "b" and "526" on one side and plain on the other side ⢠tablet, 250 mg ( 3 )
Contraindications:
4. contraindications terbinafine tablets are contraindicated in patients with: ⢠history of allergic reaction to oral terbinafine because of the risk of anaphylaxis [see adverse reactions (6.2) ] ⢠chronic or active liver disease [see warnings and precautions (5.1) ] ⢠history of allergic reaction to oral terbinafine because of the risk of anaphylaxis. ( 4 ) ⢠chronic or active liver disease. ( 4 )
Adverse Reactions:
6. adverse reactions common (greater than 2% of patients treated with terbinafine tablets) reported adverse events include headache, diarrhea, rash, dyspepsia, liver enzyme abnormalities, pruritus, taste disturbance, nausea, abdominal pain, and flatulence. ( 6.1 ). to report suspected adverse reactions, contact breckenridge pharmaceutical, inc. at 1-800-367-3395, or go to www.bpirx.com, or fda at 1-800-fda-1088 or www.fda.gov/medwatch. 6.1 clinical trials experience because clinical trials are conducted under widely varying conditions, adverse reaction rates in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. the most frequently reported adverse events observed in the 3 us/canadian placebo-controlled trials are listed in the table below. the adverse events reported encompass gastrointestinal symptoms (including diarrhea, dyspepsia, and abdominal pain), liver test abnormalities,
Read more...rashes, urticaria, pruritus, and taste disturbances. changes in the ocular lens and retina have been reported following the use of terbinafine tablets in controlled trials. the clinical significance of these changes is unknown. in general, the adverse events were mild, transient, and did not lead to discontinuation from study participation. adverse event discontinuation terbinafine (%) n=465 placebo (%) n=137 terbinafine (%) n=465 placebo (%) n=137 headache 12.9 9.5 0.2 0.0 gastrointestinal symptoms: diarrhea 5.6 2.9 0.6 0.0 dyspepsia 4.3 2.9 0.4 0.0 abdominal pain 2.4 1.5 0.4 0.0 nausea 2.6 2.9 0.2 0.0 flatulence 2.2 2.2 0.0 0.0 dermatological symptoms: rash 5.6 2.2 0.9 0.7 pruritus 2.8 1.5 0.2 0.0 urticaria 1.1 0.0 0.0 0.0 liver enzyme abnormalities liver enzyme abnormalities greater than or equal to 2Ã the upper limit of normal range. 3.3 1.4 0.2 0.0 taste disturbance 2.8 0.7 0.2 0.0 visual disturbance 1.1 1.5 0.9 0.0 6.2 postmarketing experience the following adverse events have been identified during post-approval use of terbinafine tablets. because these events are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. blood and lymphatic system disorders: pancytopenia, agranulocytosis, severe neutropenia, thrombocytopenia, anemia, thrombotic microangiopathy (tma), including thrombotic thrombocytopenic purpura and hemolytic uremic syndrome [see warnings and precautions (5.5 , 5.8) ] immune system disorders: serious hypersensitivity reactions e.g., angioedema and allergic reactions (including anaphylaxis), precipitation and exacerbation of cutaneous and systemic lupus erythematosus [see warnings and precautions (5.7) ] , serum sickness-like reaction psychiatric disorders: anxiety and depressive symptoms independent of taste disturbance have been reported with use of terbinafine tablets. in some cases, depressive symptoms have been reported to subside with discontinuance of therapy and to recur with reinstitution of therapy [see warnings and precautions (5.4) ] . nervous system disorders: cases of taste disturbance, including taste loss, have been reported with the use of terbinafine tablets. it can be severe enough to result in decreased food intake, weight loss, anxiety, and depressive symptoms. cases of smell disturbance, including smell loss, have been reported with the use of terbinafine tablets [see warnings and precautions (5.2 , 5.3) ] . cases of paresthesia and hypoesthesia have been reported with the use of terbinafine tablets. eye disorders: visual field defects, reduced visual acuity ear and labyrinth disorders: hearing impairment, vertigo, tinnitus vascular disorders: vasculitis gastrointestinal disorders: pancreatitis, vomiting hepatobiliary disorders: cases of liver failure some leading to liver transplant or death [see warnings and precautions (5.1) ] , idiosyncratic and symptomatic hepatic injury. cases of hepatitis, cholestasis, and increased hepatic enzymes [see warnings and precautions (5.1) ] have been seen with the use of terbinafine tablets. skin and subcutaneous tissue disorders: serious skin reactions [e.g., stevens-johnson syndrome, toxic epidermal necrolysis, erythema multiforme, exfoliative dermatitis, bullous dermatitis, and drug reaction with eosinophilia and systemic symptoms (dress) syndrome] [see warnings and precautions (5.6) ] , acute generalized exanthematous pustulosis, psoriasiform eruptions or exacerbation of psoriasis, photosensitivity reactions, hair loss musculoskeletal and connective tissue disorders: rhabdomyolysis, arthralgia, myalgia general disorders and administration site conditions: malaise, fatigue, influenza-like illness, pyrexia investigations: altered prothrombin time (prolongation and reduction) in patients concomitantly treated with warfarin and increased blood creatine phosphokinase have been reported
Adverse Reactions Table:
| Adverse Event | | Discontinuation | |
|---|
| terbinafine (%) n=465 | Placebo (%) n=137 | terbinafine (%) n=465 | Placebo (%) n=137 |
|---|
| Headache | 12.9 | 9.5 | 0.2 | 0.0 |
| Gastrointestinal Symptoms: | | | | |
| Diarrhea | 5.6 | 2.9 | 0.6 | 0.0 |
| Dyspepsia | 4.3 | 2.9 | 0.4 | 0.0 |
| Abdominal Pain | 2.4 | 1.5 | 0.4 | 0.0 |
| Nausea | 2.6 | 2.9 | 0.2 | 0.0 |
| Flatulence | 2.2 | 2.2 | 0.0 | 0.0 |
| Dermatological Symptoms: | | | | |
| Rash | 5.6 | 2.2 | 0.9 | 0.7 |
| Pruritus | 2.8 | 1.5 | 0.2 | 0.0 |
| Urticaria | 1.1 | 0.0 | 0.0 | 0.0 |
| Liver Enzyme AbnormalitiesLiver enzyme abnormalities greater than or equal to 2× the upper limit of normal range. | 3.3 | 1.4 | 0.2 | 0.0 |
| Taste Disturbance | 2.8 | 0.7 | 0.2 | 0.0 |
| Visual Disturbance | 1.1 | 1.5 | 0.9 | 0.0 |
Drug Interactions:
7. drug interactions terbinafine is an inhibitor of cyp450 2d6 isozyme and has an effect on metabolism of desipramine. drug interactions have also been noted with cimetidine, fluconazole, cyclosporine, rifampin, and caffeine. ( 7.1 ) 7.1 drug-drug interactions in vivo studies have shown that terbinafine is an inhibitor of the cyp450 2d6 isozyme. drugs predominantly metabolized by the cyp450 2d6 isozyme include the following drug classes: tricyclic antidepressants, selective serotonin reuptake inhibitors, beta-blockers, antiarrhythmics class 1c (e.g., flecainide and propafenone) and monoamine oxidase inhibitors type b. coadministration of terbinafine tablets should be done with careful monitoring and may require a reduction in dose of the 2d6-metabolized drug. in a study to assess the effects of terbinafine on desipramine in healthy volunteers characterized as normal metabolizers, the administration of terbinafine resulted in a 2-fold increase in c max and a 5-fold increase in area unde
Read more...r the curve (auc). in this study, these effects were shown to persist at the last observation at 4 weeks after discontinuation of terbinafine tablets. in studies in healthy subjects characterized as extensive metabolizers of dextromethorphan (antitussive drug and cyp2d6 probe substrate), terbinafine increases the dextromethorphan/ dextrorphan metabolite ratio in urine by 16- to 97-fold on average. thus, terbinafine may convert extensive cyp2d6 metabolizers to poor metabolizer status. in vitro studies with human liver microsomes showed that terbinafine does not inhibit the metabolism of tolbutamide, ethinylestradiol, ethoxycoumarin, cyclosporine, cisapride and fluvastatin. in vivo drug-drug interaction studies conducted in healthy volunteer subjects showed that terbinafine does not affect the clearance of antipyrine or digoxin. terbinafine decreases the clearance of caffeine by 19%. terbinafine increases the clearance of cyclosporine by 15%. the influence of terbinafine on the pharmacokinetics of fluconazole, cotrimoxazole (trimethoprim and sulfamethoxazole), zidovudine or theophylline was not considered to be clinically significant. coadministration of a single dose of fluconazole (100 mg) with a single dose of terbinafine resulted in a 52% and 69% increase in terbinafine c max and auc, respectively. fluconazole is an inhibitor of cyp2c9 and cyp3a enzymes. based on this finding, it is likely that other inhibitors of both cyp2c9 and cyp3a4 (e.g., ketoconazole, amiodarone) may also lead to a substantial increase in the systemic exposure (c max and auc) of terbinafine when concomitantly administered. there have been spontaneous reports of increase or decrease in prothrombin times in patients concomitantly taking oral terbinafine and warfarin, however, a causal relationship between terbinafine tablets and these changes has not been established. terbinafine clearance is increased 100% by rifampin, a cyp450 enzyme inducer, and decreased 33% by cimetidine, a cyp450 enzyme inhibitor. terbinafine clearance is unaffected by cyclosporine. there is no information available from adequate drug-drug interaction studies with the following classes of drugs: oral contraceptives, hormone replacement therapies, hypoglycemics, phenytoins, thiazide diuretics, and calcium channel blockers. 7.2 food interactions an evaluation of the effect of food on terbinafine tablets was conducted. an increase of less than 20% of the auc of terbinafine was observed when terbinafine tablets were administered with food. terbinafine tablets can be taken with or without food.
Use in Specific Population:
8. use in specific populations 8.1 pregnancy pregnancy category b there are no adequate and well-controlled studies in pregnant women. because animal reproduction studies are not always predictive of human response, and because treatment of onychomycosis can be postponed until after pregnancy is completed, it is recommended that terbinafine tablets not be initiated during pregnancy. oral reproduction studies have been performed in rabbits and rats at doses up to 300 mg/kg/day [12Ã to 23Ã the maximum recommended human dose (mrhd), in rabbits and rats, respectively, based on body surface area (bsa) comparisons] and have revealed no evidence of impaired fertility or harm to the fetus due to terbinafine. 8.3 nursing mothers after oral administration, terbinafine is present in breast milk of nursing mothers. the ratio of terbinafine in milk to plasma is 7:1. treatment with terbinafine tablets is not recommended in women who are nursing. 8.4 pediatric use the safety and efficacy of ter
Read more...binafine tablets have not been established in pediatric patients with onychomycosis. 8.5 geriatric use clinical studies of terbinafine tablets did not include sufficient numbers of subjects aged 65 years and over to determine whether they respond differently from younger subjects. other reported clinical experience has not identified differences in responses between the elderly and younger patients. in general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy. 8.6 renal impairment in patients with renal impairment (creatinine clearance less than or equal to 50 ml/min), the use of terbinafine tablets has not been adequately studied. 8.7 hepatic impairment terbinafine tablets are contraindicated for patients with chronic or active liver disease [see contraindications (4) and warnings and precautions (5.1) ] . cases of liver failure, some leading to liver transplant or death, have occurred with the use of terbinafine tablets in individuals with and without preexisting liver disease. the severity of hepatic events and/or their outcome may be worse in patients with active or chronic liver disease.
Use in Pregnancy:
8.1 pregnancy pregnancy category b there are no adequate and well-controlled studies in pregnant women. because animal reproduction studies are not always predictive of human response, and because treatment of onychomycosis can be postponed until after pregnancy is completed, it is recommended that terbinafine tablets not be initiated during pregnancy. oral reproduction studies have been performed in rabbits and rats at doses up to 300 mg/kg/day [12Ã to 23Ã the maximum recommended human dose (mrhd), in rabbits and rats, respectively, based on body surface area (bsa) comparisons] and have revealed no evidence of impaired fertility or harm to the fetus due to terbinafine.
Pediatric Use:
8.4 pediatric use the safety and efficacy of terbinafine tablets have not been established in pediatric patients with onychomycosis.
Geriatric Use:
8.5 geriatric use clinical studies of terbinafine tablets did not include sufficient numbers of subjects aged 65 years and over to determine whether they respond differently from younger subjects. other reported clinical experience has not identified differences in responses between the elderly and younger patients. in general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
Overdosage:
10. overdosage clinical experience regarding overdose with oral terbinafine is limited. doses up to 5 grams (20 times the therapeutic daily dose) have been taken without inducing serious adverse reactions. the symptoms of overdose included nausea, vomiting, abdominal pain, dizziness, rash, frequent urination, and headache.
Description:
11. description terbinafine tablets, usp contain the synthetic allylamine antifungal compound terbinafine hydrochloride. chemically, terbinafine hydrochloride is (e)- n -(6,6-dimethyl-2-hepten-4-ynyl)- n -methyl-1-naphthalenemethanamine hydrochloride. the empirical formula c 21 h 26 cln with a molecular weight of 327.90, and the following structural formula: terbinafine hydrochloride is a white to off-white fine crystalline powder. it is freely soluble in methanol and methylene chloride, soluble in ethanol, and slightly soluble in water. each tablet contains: active ingredients: terbinafine hydrochloride (equivalent to 250 mg base). inactive ingredients: colloidal silicon dioxide, hypromellose, magnesium stearate, microcrystalline cellulose and sodium starch glycolate chemical structure
Clinical Pharmacology:
12. clinical pharmacology 12.1 mechanism of action terbinafine is an allylamine antifungal [see clinical pharmacology (12.4) ] . 12.2 pharmacodynamics the pharmacodynamics of terbinafine tablets is unknown. 12.3 pharmacokinetics following oral administration, terbinafine is well absorbed (greater than 70%) and the bioavailability of terbinafine tablets as a result of first-pass metabolism is approximately 40%. peak plasma concentrations of 1 mcg/ml appear within 2 hours after a single 250 mg dose; the auc is approximately 4.56 mcgâ¢h/ml. an increase in the auc of terbinafine of less than 20% is observed when terbinafine tablets are administered with food. in plasma, terbinafine is greater than 99% bound to plasma proteins and there are no specific binding sites. at steady-state, in comparison to a single dose, the peak concentration of terbinafine is 25% higher and plasma auc increases by a factor of 2.5; the increase in plasma auc is consistent with an effective half-life of ~36 h
Read more...ours. terbinafine is distributed to the sebum and skin. a terminal half-life of 200-400 hours may represent the slow elimination of terbinafine from tissues such as skin and adipose. prior to excretion, terbinafine is extensively metabolized by at least 7 cyp isoenzymes with major contributions from cyp2c9, cyp1a2, cyp3a4, cyp2c8, and cyp2c19. no metabolites have been identified that have antifungal activity similar to terbinafine. approximately 70% of the administered dose is eliminated in the urine. in patients with renal impairment (creatinine clearance less than or equal to 50 ml/min) or hepatic cirrhosis, the clearance of terbinafine is decreased by approximately 50% compared to normal volunteers. no effect of gender on the blood levels of terbinafine was detected in clinical trials. no clinically relevant age-dependent changes in steady-state plasma concentrations of terbinafine have been reported. 12.4 microbiology terbinafine, an allylamine antifungal, inhibits biosynthesis of ergosterol, an essential component of fungal cell membrane, via inhibition of squalene epoxidase enzyme. this results in fungal cell death primarily due to the increased membrane permeability mediated by the accumulation of high concentrations of squalene but not due to ergosterol deficiency. depending on the concentration of the drug and the fungal species test in vitro , terbinafine hydrochloride may be fungicidal. however, the clinical significance of in vitro data is unknown. terbinafine has been shown to be active against most strains of the following microorganisms both in vitro and in clinical infections: trichophyton mentagrophytes trichophyton rubrum the following in vitro data are available, but their clinical significance is unknown. in vitro , terbinafine exhibits satisfactory mic's against most strains of the following microorganisms; however, the safety and efficacy of terbinafine in treating clinical infections due to these microorganisms have not been established in adequate and well-controlled clinical trials: candida albicans epidermophyton floccosum scopulariopsis brevicaulis
Mechanism of Action:
12.1 mechanism of action terbinafine is an allylamine antifungal [see clinical pharmacology (12.4) ] .
Pharmacodynamics:
12.2 pharmacodynamics the pharmacodynamics of terbinafine tablets is unknown.
Pharmacokinetics:
12.3 pharmacokinetics following oral administration, terbinafine is well absorbed (greater than 70%) and the bioavailability of terbinafine tablets as a result of first-pass metabolism is approximately 40%. peak plasma concentrations of 1 mcg/ml appear within 2 hours after a single 250 mg dose; the auc is approximately 4.56 mcgâ¢h/ml. an increase in the auc of terbinafine of less than 20% is observed when terbinafine tablets are administered with food. in plasma, terbinafine is greater than 99% bound to plasma proteins and there are no specific binding sites. at steady-state, in comparison to a single dose, the peak concentration of terbinafine is 25% higher and plasma auc increases by a factor of 2.5; the increase in plasma auc is consistent with an effective half-life of ~36 hours. terbinafine is distributed to the sebum and skin. a terminal half-life of 200-400 hours may represent the slow elimination of terbinafine from tissues such as skin and adipose. prior to excretion, terb
Read more...inafine is extensively metabolized by at least 7 cyp isoenzymes with major contributions from cyp2c9, cyp1a2, cyp3a4, cyp2c8, and cyp2c19. no metabolites have been identified that have antifungal activity similar to terbinafine. approximately 70% of the administered dose is eliminated in the urine. in patients with renal impairment (creatinine clearance less than or equal to 50 ml/min) or hepatic cirrhosis, the clearance of terbinafine is decreased by approximately 50% compared to normal volunteers. no effect of gender on the blood levels of terbinafine was detected in clinical trials. no clinically relevant age-dependent changes in steady-state plasma concentrations of terbinafine have been reported.
Nonclinical Toxicology:
13. nonclinical toxicology 13.1 carcinogenesis, mutagenesis, impairment of fertility in a 28-month oral carcinogenicity study in rats, an increase in the incidence of liver tumors was observed in males at the highest dose tested, 69 mg/kg/day (2Ã the mrhd based on auc comparisons of the parent terbinafine); however, even though dose-limiting toxicity was not achieved at the highest tested dose, higher doses were not tested. the results of a variety of in vitro (mutations in e. coli and s. typhimurium , dna repair in rat hepatocytes, mutagenicity in chinese hamster fibroblasts, chromosome aberration, and sister chromatid exchanges in chinese hamster lung cells), and in vivo (chromosome aberration in chinese hamsters, micronucleus test in mice) genotoxicity tests gave no evidence of a mutagenic or clastogenic potential. oral reproduction studies in rats at doses up to 300 mg/kg/day (approximately 12Ã the mrhd based on bsa comparisons) did not reveal any specific effects on fertilit
Read more...y or other reproductive parameters. intravaginal application of terbinafine hydrochloride at 150 mg/day in pregnant rabbits did not increase the incidence of abortions or premature deliveries nor affect fetal parameters. 13.2 animal toxicology and/or pharmacology a wide range of in vivo studies in mice, rats, dogs, and monkeys, and in vitro studies using rat, monkey, and human hepatocytes suggest that peroxisome proliferation in the liver is a rat-specific finding. however, other effects, including increased liver weights and aptt, occurred in dogs and monkeys at doses giving c ss trough levels of the parent terbinafine 2-3Ã those seen in humans at the mrhd. higher doses were not tested.
Carcinogenesis and Mutagenesis and Impairment of Fertility:
13.1 carcinogenesis, mutagenesis, impairment of fertility in a 28-month oral carcinogenicity study in rats, an increase in the incidence of liver tumors was observed in males at the highest dose tested, 69 mg/kg/day (2Ã the mrhd based on auc comparisons of the parent terbinafine); however, even though dose-limiting toxicity was not achieved at the highest tested dose, higher doses were not tested. the results of a variety of in vitro (mutations in e. coli and s. typhimurium , dna repair in rat hepatocytes, mutagenicity in chinese hamster fibroblasts, chromosome aberration, and sister chromatid exchanges in chinese hamster lung cells), and in vivo (chromosome aberration in chinese hamsters, micronucleus test in mice) genotoxicity tests gave no evidence of a mutagenic or clastogenic potential. oral reproduction studies in rats at doses up to 300 mg/kg/day (approximately 12Ã the mrhd based on bsa comparisons) did not reveal any specific effects on fertility or other reproductive par
Read more...ameters. intravaginal application of terbinafine hydrochloride at 150 mg/day in pregnant rabbits did not increase the incidence of abortions or premature deliveries nor affect fetal parameters.
Clinical Studies:
14. clinical studies the efficacy of terbinafine tablets in the treatment of onychomycosis is illustrated by the response of subjects with toenail and/or fingernail infections who participated in 3 us/canadian placebo-controlled clinical trials. results of the first toenail trial, as assessed at week 48 (12 weeks of treatment with 36 weeks follow-up after completion of therapy), demonstrated mycological cure, defined as simultaneous occurrence of negative koh plus negative culture, in 70% of subjects. fifty-nine percent (59%) of subjects experienced effective treatment (mycological cure plus 0% nail involvement or greater than 5mm of new unaffected nail growth); 38% of subjects demonstrated mycological cure plus clinical cure (0% nail involvement). in a second toenail trial of dermatophytic onychomycosis, in which nondermatophytes were also cultured, similar efficacy against the dermatophytes was demonstrated. the pathogenic role of the nondermatophytes cultured in the presence of derm
Read more...atophytic onychomycosis has not been established. the clinical significance of this association is unknown. results of the fingernail trial, as assessed at week 24 (6 weeks of treatment with 18 weeks follow-up after completion of therapy), demonstrated mycological cure in 79% of subjects, effective treatment in 75% of the subjects, and mycological cure plus clinical cure in 59% of the subjects. the mean time to overall success was approximately 10 months for the first toenail trial and 4 months for the fingernail trial. in the first toenail trial, for subjects evaluated at least 6 months after achieving clinical cure and at least 1 year after completing therapy with terbinafine tablets, the clinical relapse rate was approximately 15%.
How Supplied:
16. how supplied/storage and handling terbinafine tablets, usp are supplied as white, oblong, unscored tablets debossed "b" and "526" on one side and plain on the other side. bottles of 14 tablets ndc 71205-127-14 bottles of 15 tablets ndc 71205-127-15 bottles of 30 tablets ndc 71205-127-30 bottles of 35 tablets ndc 71205-127-35 bottles of 42 tablets ndc 71205-127-42 bottles of 45 tablets ndc 71205-127-45 bottles of 60 tablets ndc 71205-127-60 bottles of 90 tablets ndc 71205-127-90 store terbinafine tablets, usp at 20° - 25°c (68° - 77°f) [see usp controlled room temperature].
Information for Patients:
17. patient counseling information advise the patient to read the fda-approved medication guide. patients taking terbinafine tablets should receive the following information and instructions: ⢠advise patients to immediately report to their physician or get emergency help if they experience any of the following symptoms: hives, mouth sores, blistering and peeling of skin, swelling of face, lips, tongue, or throat, difficulty swallowing or breathing. terbinafine tablets treatment should be discontinued. ⢠advise patients to immediately report to their physician any symptoms of persistent nausea, anorexia, fatigue, vomiting, right upper abdominal pain, jaundice, dark urine, or pale stools. terbinafine tablets treatment should be discontinued. ⢠advise patients to report to their physician any signs of taste disturbance, smell disturbance and/or depressive symptoms, fever, skin eruption, lymph node enlargement, erythema, scaling, loss of pigment, and unusual photosensitivit
Read more...y that can result in a rash. terbinafine tablets treatment should be discontinued. ⢠advise patients to minimize exposure to natural and artificial sunlight (tanning beds or uva/b treatment) while using terbinafine tablets. ⢠advise patients that if they forget to take terbinafine tablets, to take their tablets as soon as they remember, unless it is less than 4 hours before the next dose is due. ⢠advise patients to call their physician if they take too many terbinafine tablets.
Package Label Principal Display Panel:
Principal display panel - 250 mg tablet bottle label ndc 71205-127-14 terbinafine tablets, usp 250 mg pharmacist: dispense the medication guide provided separately to each patient. rx only 14 tablets 71205-127-14