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.

Rare adverse events, based on worldwide experience with LAMISIL® (terbinafine hydrochloride tablets) Tablets use, include: idiosyncratic and symptomatic hepatic injury and more rarely, cases of liver failure, some leading to death or liver transplant, (see WARNINGS and PRECAUTIONS), serious skin reactions (see WARNINGS), severe neutropenia (see PRECAUTIONS), thrombocytopenia, angioedema and allergic reactions (including anaphylaxis). Precipitation and exacerbation of cutaneous and systemic lupus erythematosus have been reported infrequently in patients taking LAMISIL® . Uncommonly, LAMISIL® may cause taste disturbance (including taste loss) which usually recovers within several weeks after discontinuation of the drug. There have been isolated reports of prolonged (greater than one year) taste disturbance. Rarely, taste disturbances associated with oral terbinafine have been reported to be severe enough to result in decreased food intake leading to significant and unwanted weight loss.

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 LAMISIL® Tablets and agranulocytosis (rare).

In vivo studies have shown that terbinafine is an inhibitor of the CYP450 2D6 isozyme. Coadministration of LAMISIL® with drugs predominantly metabolized by the CYP450 2D6 isozyme (e.g., tricyclic antidepressants, selective serotonin reuptake inhibitors, beta-blockers and monoamine oxidase inhibitors Type B) 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 Cmax and a 5-fold increase in AUC. In this study, these effects were shown to persist at the last observation at 4 weeks after discontinuation of LAMISIL®.

In vitro studies with human liver microsomes showed that terbinafine does not inhibit the metabolism of tolbutamide, ethinylestradiol, ethoxycoumarin, and cyclosporine.

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%.

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 LAMISIL® 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.

Bookmark this page: