TERBINAFINE HYDROCHLORIDE- terbinafine hydrochloride_tablet

CLINICAL PHARMACOLOGY
Following oral administration, terbinafine is well absorbed (>70%) and the bioavailability of Terbinafine Hydrochloride Tablets as a result of first-pass metabolism is approximately 40%. Peak plasma concentrations of 1 mug/mL appear within 2 h after a single 250 mg dose; the AUC (area under the curve) is approximately 4. 56 mug∙h/mL. An increase in the AUC of terbinafine of less than 20% is observed when terbinafine hydrochloride is administered with food. No clinically relevant age-dependent changes in steady-state plasma concentrations of terbinafine have been reported. In patients with renal impairment (creatinine clearance <= 50mL/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. In plasma, terbinafine is >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 200en dash400 h may represent the slow elimination of terbinafine from tissues such as skin and adipose. Prior to excretion, terbinafine is extensively metabolized. No metabolites have been identified that have antifungal activity similar to terbinafine. Approximately 70% of the administered dose is eliminated in the urine. Terbinafine hydrochloride is a synthetic allylamine derivative. Terbinafine hydrochloride is hypothesized to act by inhibiting squalene epoxidase, thus blocking the biosynthesis of ergosterol, an essential component of fungal cell membranes. In vitro in vitro in vitro in vitro Trichophyton mentagrophytes Trichophyton rubrum The following in vitro In vitro, Candida albicans Epidermophyton floccosum Scopulariopsis brevicaulis.
Pharmacokinetics
Following oral administration, terbinafine is well absorbed (>70%) and the bioavailability of Terbinafine Hydrochloride Tablets as a result of first-pass metabolism is approximately 40%. Peak plasma concentrations of 1 mug/mL appear within 2 h after a single 250 mg dose; the AUC (area under the curve) is approximately 4.56 mug∙h/mL. An increase in the AUC of terbinafine of less than 20% is observed when terbinafine hydrochloride is administered with food. No clinically relevant age-dependent changes in steady-state plasma concentrations of terbinafine have been reported. In patients with renal impairment (creatinine clearance <= 50mL/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. In plasma, terbinafine is >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 200en dash400 h may represent the slow elimination of terbinafine from tissues such as skin and adipose. Prior to excretion, terbinafine is extensively metabolized. No metabolites have been identified that have antifungal activity similar to terbinafine. Approximately 70% of the administered dose is eliminated in the urine.
Microbiology
Terbinafine hydrochloride is a synthetic allylamine derivative. Terbinafine hydrochloride is hypothesized to act by inhibiting squalene epoxidase, thus blocking the biosynthesis of ergosterol, an essential component of fungal cell membranes. In vitro in vitro in vitro in vitro Trichophyton mentagrophytes Trichophyton rubrum The following in vitro In vitro, Candida albicans Epidermophyton floccosum Scopulariopsis brevicaulis
ANIMAL TOXICOLOGY
A wide range of in vivo in vitro

Terbinafine Hydrochloride Tablets are indicated for the treatment of onychomycosis of the toenail or fingernail due to dermatophytes (tinea unguium) (see DOSAGE AND ADMINISTRATION CLINICAL STUDIES Prior to initiating treatment, appropriate nail specimens for laboratory testing (KOH preparation, fungal culture, or nail biopsy) should be obtained to confirm the diagnosis of onychomycosis.

Terbinafine Hydrochloride Tablets, one 250 mg tablet, should be taken once daily for 6 weeks by patients with fingernail onychomycosis. Terbinafine hydrochloride, one 250 mg tablet, should be taken once daily for 12 weeks by patients with toenail onychomycosis. 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.

The most frequently reported adverse events observed in the three 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, rashes, urticaria, pruritus, and taste disturbances. In general, the adverse events were mild, transient, and did not lead to discontinuation from study participation. Adverse Event Discontinuation Terbinafine Hydrochloride Tablets Placebo Terbinafine Hydrochloride Tablets Placebo (%) (%) (%) (%) 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 >= 2x the upper limit of the 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 Adverse events, based on worldwide experience with Terbinafine Hydrochloride Tablets use, include: idiosyncratic and symptomatic hepatic injury and more rarely, cases of liver failure, some leading to death or liver transplant, (see WARNINGS PRECAUTIONS WARNINGS PRECAUTIONS Other adverse reactions which have been reported include malaise, fatigue, vomiting, arthralgia, myalgia, and hair loss. Clinical adverse effects reported spontaneously since the drug was marketed include altered prothrombin time (prolongation and reduction) in patients concomitantly treated with warfarin and Terbinafine Hydrochloride Tablets and agranulocytosis (rare).

Terbinafine Hydrochloride Tablets are contraindicated in individuals with hypersensitivity to terbinafine or to any other ingredients of the formulation.

Pregnancy
Oral reproduction studies have been performed in rabbits and rats at doses up to 300 mg/kg/day (12x to 23x the MRHD, in rabbits and rats, respectively, based on BSA) and have revealed no evidence of impaired fertility or harm to the fetus due to terbinafine. There are, however, 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 hydrochloride not be initiated during pregnancy.
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 hydrochloride is not recommended in nursing mothers.
Pediatric Use
The safety and efficacy of Terbinafine Hydrochloride Tablets have not been established in pediatric patients.

In vivo max In vitro In vivo Terbinafine decreases the clearance of caffeine by 19%. Terbinafine increases the clearance of cyclosporine by 15%. 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 Hydrochloride 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, theophyllines, phenytoins, thiazide diuretics, and calcium channel blockers.

CLINICAL STUDIES
The efficacy of Terbinafine Hydrochloride Tablets in the treatment of onychomycosis is illustrated by the response of patients with toenail and/or fingernail infections who participated in three US/Canadian placebo-controlled clinical trials. Results of the first toenail study, 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 patients. Fifty-nine percent (59%) of patients experienced effective treatment (mycological cure plus 0% nail involvement or >5mm of new unaffected nail growth); 38% of patients demonstrated mycological cure plus clinical cure (0% nail involvement). In a second toenail study of dermatophytic onychomycosis, in which non-dermatophytes were also cultured, similar efficacy against the dermatophytes was demonstrated. The pathogenic role of the non-dermatophytes cultured in the presence of dermatophytic onychomycosis has not been established. The clinical significance of this association is unknown. Results of the fingernail study, as assessed at week 24 (6 weeks of treatment with 18 weeks follow-up after completion of therapy), demonstrated mycological cure in 79% of patients, effective treatment in 75% of the patients, and mycological cure plus clinical cure in 59% of the patients. The mean time to overall success was approximately 10 months for the first toenail study and 4 months for the fingernail study. In the first toenail study, for patients evaluated at least six months after achieving clinical cure and at least one year after completing terbinafine hydrochloride therapy, the clinical relapse rate was approximately 15%.
WARNINGS
Rare cases of liver failure, some leading to death or liver transplant, have occurred with the use of Terbinafine Hydrochloride Tablets for the treatment of onychomycosis in individuals with and without pre-existing liver disease. In the majority of liver cases reported in association with terbinafine hydrochloride use, the patients had serious underlying systemic conditions and an uncertain causal association with terbinafine hydrochloride. The severity of hepatic events and/or their outcome may be worse in patients with active or chronic liver disease (see PRECAUTIONS PRECAUTIONS There have been isolated reports of serious skin reactions (e.g., Stevens-Johnson Syndrome and toxic epidermal necrolysis). If progressive skin rash occurs, treatment with terbinafine hydrochloride should be discontinued.
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 [2x the Maximum Recommended Human Dose (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 E. coli S. typhimurium, in vivo
OVERDOSAGE
Clinical experience regarding overdose with Terbinafine Hydrochloride Tablets 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.

Wockhardt USA, LLC

TERBINAFINE HYDROCHLORIDE- terbinafine hydrochloride_tablet Product manual source documgent