Brands, Medical Use, Clinical Data
- Trypanocidal Agents
Brands / Synonyms
Bramazil; Lamasil; Lamisil; Lamisil AT; Terbina; Terbinafine HCl; Terbinafine hydrochloride; Ternbinafine HCl
For the treatment of interdigital tinea infections.
Terbinafine is an allylamine antifungal agent and acts by inhibiting squalene epoxidase, thus blocking the biosynthesis of ergosterol, an essential component of fungal cell membranes. in vitro, mammalian squalene epoxidase is only inhibited at higher (4000 fold) concentrations than is needed for inhibition of the dermatophyte enzyme. Depending on the concentration of the drug and the fungal species test in vitro, Terbinafine may be fungicidal. However, the clinical significance of in vitro data is unknown.
Mechanism of Action
Terbinafine is hypothesized to act by inhibiting squalene epoxidase, thus blocking the biosynthesis of ergosterol, an essential component of fungal cell membranes.
Readily absorbed from gastrointestinal tract.
Biotrnasformation / Drug Metabolism
LAMISIL® (terbinafine hydrochloride tablets) Tablets are contraindicated in
individuals with hypersensitivity to terbinafine or to any other ingredients of the formulation.
In vitro studies with human liver microsomes showed that terbinafine does not inhibit the
metabolism of tolbutamide, ethinylestradiol, ethoxycoumarin, and cyclosporine. In vitro studies have also
shown that terbinafine inhibits CYP2D6-mediated metabolism. This may be of clinical relevance for compounds
predominantly metabolized by this enzyme, such as tricyclic antidepressants, ß-blockers, selective serotonin
reuptake inhibitors (SSRIs), and monoamine oxidase inhibitors (MAO-Is) Type B, if they have a narrow therapeutic
In vivo drug-drug interaction studies conducted in normal 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, beta blockers, and calcium channel blockers.