PACKAGE LABEL-PRINCIPAL DISPLAY PANEL - 250 mg (100 Tablet Bottle)
Terbafin Tablets, USP 250 mg
PHARMACIST: Dispense the Medication Guide provided separately to each patient.
100 Tablets NORTHSTARX TM
Terbafin tablets, USP contain the synthetic allylamine antifungal compound Terbafin hydrochloride USP.
Chemically, Terbafin hydrochlor >N -(6,6-dimethyl-2-hepten-4-ynyl)- N -methyl-1-naphthalenemethanamine hydrochlor >21 H 26 ClN with a molecular weight of 327.90, and the following structural formula:
In vivo studies have shown that Terbafin 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 Lamisil 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 Terbafin on desipramine in healthy volunteers characterized as normal metabolizers, the administration of Terbafin resulted in a 2-fold increase in Cmax and a 5-fold increase in area under the curve (AUC). In this study, these effects were shown to persist at the last observation at 4 weeks after discontinuation of Lamisil Tablets. In studies in healthy subjects characterized as extensive metabolizers of dextromethorphan (antitussive drug and CYP2D6 probe substrate), Terbafin increases the dextromethorphan/dextrorphan metabolite ratio in urine by 16- to 97-fold on average. Thus, Terbafin may convert extensive CYP2D6 metabolizers to poor metabolizer status.
In vitro studies with human liver microsomes showed that Terbafin 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 Terbafin does not affect the clearance of antipyrine or digoxin. Terbafin decreases the clearance of caffeine by 19%. Terbafin increases the clearance of cyclosporine by 15%.
The influence of Terbafin 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 Terbafin resulted in a 52% and 69% increase in Terbafin Cmax 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 (Cmax and AUC) of Terbafin when concomitantly administered.
There have been spontaneous reports of increase or decrease in prothrombin times in patients concomitantly taking oral Terbafin and warfarin, however, a causal relationship between Lamisil Tablets and these changes has not been established.
Terbafin clearance is increased 100% by rifampin, a CYP450 enzyme inducer, and decreased 33% by cimetidine, a CYP450 enzyme inhibitor. Terbafin 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.
COMMON BRAND(S): Lamisil
GENERIC NAME(S): Terbafin Hcl
OTHER NAME(S): Terbafin Hcl Tablet
Terbafin is used to treat certain types of fungal infections (e.g., fingernail or toenail). It works by stopping the growth of fungus. This medication belongs to a class of drugs known as antifungals.
Cases of liver failure, some leading to liver transplant or death, have occurred with the use of Lamisil Tablets in individuals with and without preexisting liver disease.
In the majority of liver cases reported in association with use of Lamisil 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. Treatment with Lamisil Tablets should be discontinued if biochemical or clinical evidence of liver injury develops.
Lamisil Tablets are not recommended for patients with chronic or active liver disease. Before prescribing Lamisil Tablets, liver function tests should be performed since hepatotoxicity may occur in patients with and without pre-existing liver disease. Periodic monitoring of liver function tests is recommended. Lamisil should be immediately discontinued in case of elevation of liver function tests. Patients prescribed Lamisil Tablets should be warned to report immediately to their physician any symptoms of persistent nausea, anorexia, fatigue, vomiting, right upper abdominal pain or jaundice, dark urine, or pale stools. Patients with these symptoms should discontinue taking oral Terbafin, and the patientâ€™s liver function should be immediately evaluated.