Terbinafine Tablets

— THERAPEUTIC CATEGORIES —
  • Fungal infections
PAGE CONTENTS
  • Jump to Section
  • Generic Name & Formulations
  • Indications
  • Dosage and Administration
  • Contraindications
  • Boxed Warnings
  • Warnings/Precautions
  • Pharmacokinetics
  • Interactions
  • Adverse Reactions
  • Clinical Trials
  • Note
  • Patient Counseling

    • Terbinafine Tablets Generic Name & Formulations

    Legal Class

    Rx

    General Description

    Terbinafine HCl 250mg.

    Pharmacological Class

    Allylamine antifungal.

    How Supplied

    Contact supplier

    Storage

    Store at 20°-25°C (68°-77°F) [see USP Controlled Room Temperature]; in a tight container. Protect from light.

    Manufacturer

    Various generic manufacturers

    Mechanism of Action

    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.

    Terbinafine Tablets Indications

    Indications

    Onychomycosis of the toenail or fingernail due to tinea unguium.

    Terbinafine Tablets Dosage and Administration

    Adult

    250mg once daily for 6 weeks (fingernail) or 12 weeks (toenail).

    Children

    Not established.

    Terbinafine Tablets Contraindications

    Contraindications

    Chronic or active liver disease.

    Terbinafine Tablets Boxed Warnings

    Not Applicable

    Terbinafine Tablets Warnings/Precautions

    Warnings/Precautions

    Onychomycosis: confirm diagnosis with nail specimen. Perform LFTs prior to and periodically during treatment. Discontinue if hepatic injury, progressive skin rash (eg, Stevens-Johnson syndrome, toxic epidermal necrolysis, DRESS), taste/smell disturbances, severe neutropenia (neutrophils ≤1000 cells/mm3), thrombotic microangiopathy occur, or if lupus erythematosus is suspected. Monitor CBCs if immunodeficient. Renal impairment (CrCl <50mL/min). Pregnancy (Cat.B), nursing mothers: not recommended.

    Warnings/Precautions

    Hepatotoxicity

    • Cases of liver failure, some leading to liver transplant or death, have occurred.

    • The severity of hepatic events and/or their outcome may be worse in patients with active or chronic liver disease. Discontinue if biochemical or clinical evidence of liver injury develops.

    • Patients with chronic or active liver disease: not recommended. Assess whether or not the patient has pre-existing liver disease before prescribing terbinafine tablets.

    Taste Disturbance Including Loss of Taste

    • Taste disturbance, including taste loss, has been reported. Taste disturbance may resolve within several weeks after stopping treatment, or it may last greater than 1 year, or may be permanent.

    • Discontinue if taste disturbance occurs.

    Smell Disturbance Including Loss of Smell

    • Smell disturbance, including loss of smell, has been reported. Smell disturbance may resolve after stopping treatment, or it may last greater than 1 year, or may be permanent.

    • Discontinue if smell disturbance occurs.

    Depressive Symptoms

    • Instruct patients to report depressive symptoms to their physician.

    Hematologic Effects

    • Transient decreases in absolute lymphocyte counts (ALC) have been observed. Consider monitoring CBCs in patients with known or suspected immunodeficiency if treatment continues for more than 6 weeks.

    • Cases of severe neutropenia have been reported. Obtain CBCs if signs/symptoms suggestive of secondary infection occur. Discontinue and initiate supportive management if neutrophil count is <1,000 cells/mm3.

    Skin Reactions

    • Serious skin reactions have been reported (eg, Stevens-Johnson Syndrome and toxic epidermal necrolysis). Discontinue if progressive skin rash occurs.

    Lupus Erythematosus

    • Precipitation and exacerbation of cutaneous and systemic lupus erythematosus have been reported. Discontinue if signs and symptoms suggestive of lupus erythematosus.

    Laboratory Monitoring

    • Measurement of serum transaminases (ALT and AST) is advised for all patients before taking terbinafine tablets.

    Pregnancy Considerations

    Pregnancy Category B

    • No adequate and well-controlled studies in pregnant women.

    • It is not recommended to initiate terbinafine during pregnancy.

    Nursing Mother Considerations

    • Terbinafine is present in breast milk of nursing mothers.

    • It is not recommended to initiate terbinafine in nursing mothers.

    Pediatric Considerations

    The safety and efficacy of terbinafine have not been established in pediatric patients with onychomycosis.

    Geriatric Considerations

    In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range.

    Terbinafine Tablets Pharmacokinetics

    Absorption

    Terbinafine is well absorbed (>70%) and the bioavailability is ~40%. Peak plasma concentrations of 1 μg/mL appear within 2 hours after a single 250 mg dose.

    Distribution

    >99% plasma prot

    Extensively metabolized by at least 7 CYP isoenzymes, including CYP2C9, CYP1A2, CYP3A4, CYP2C8 and CYP2C19.

    ein bound.

    Metabolism

    Extensively metabolized by at least 7 CYP isoenzymes, including CYP2C9, CYP1A2, CYP3A4, CYP2C8 and CYP2C19.

    Elimination

    Renal (70%). Terminal half-life: 200–400 hours.

    Terbinafine Tablets Interactions

    Interactions

    Antagonized by rifampin. May be potentiated by cimetidine or CYP2C9 and CYP3A4 inhibitors (eg, fluconazole, ketoconazole, amiodarone). May potentiate caffeine or drugs metabolized by CYP2D6 (eg, tricyclic antidepressants, SSRIs, beta-blockers). May antagonize cyclosporine.

    Terbinafine Tablets Adverse Reactions

    Adverse Reactions

    Headache, diarrhea, rash, dyspepsia, liver enzyme abnormalities, pruritus, taste disturbances, nausea, abdominal pain, flatulence, urticaria; hepatotoxicity, depressive symptoms, smell disturbances.

    Terbinafine Tablets Clinical Trials

    Clinical Trials

    The efficacy of terbinafine tablets in the treatment of onychomycosis is evaluated in 3 US/Canadian placebo-controlled clinical trials which included patients with toenail and/or fingernail infections.  

    • In the first toenail study, results showed that 70% of patients achieved demonstrated mycological cure at week 48 (12 weeks of treatment with 36 weeks follow-up after completion of therapy), defined as simultaneous occurrence of negative KOH plus negative culture. Moreover, 59% of patients achieved effective treatment (mycological cure plus 0% nail involvement or >5mm of new unaffected nail growth); 38% of patients achieved 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 showed that 79% of patients achieved mycological cure as assessed at week 24 (6 weeks of treatment with 18 weeks follow-up after completion of therapy), 75% of the patients achieved effective treatment, and 59% of the patients achieved mycological cure plus clinical cure.  

    • 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%.

    Terbinafine Tablets Note

    Notes

    Formerly known under the brand name Lamisil.

    Terbinafine Tablets Patient Counseling

    Patient Counseling

    • Advise patients that the optimal clinical effect is seen some months after mycological cure and cessation of treatment due to the time period required for outgrowth of healthy nail.

    • Advise patients to report to their physician any signs of taste or smell disturbance, and/or depressive symptoms. Discontinue using terbinafine tablets if these reactions occur.

    • Advise patients to report to their physician any symptoms of persistent nausea, anorexia, fatigue, vomiting, right upper abdominal pain, jaundice, dark urine or pale stools. Discontinue using terbinafine tablets if these reactions occur.

    • Advise patients to report to their physician if any of the following symptoms occur: hives, mouth sores, blistering and peeling of skin, swelling of face, lips, tongue, or throat, difficulty swallowing or breathing. Discontinue using terbinafine tablets if these reactions occur.

    • Advise to report to their physician if any symptoms of new onset or worsening lupus erythematosus. Discontinue using terbinafine tablets if this occurs.

    • Advise patients to minimize exposure to natural and artificial sunlight during treatment.

    • Prior to initiating treatment, advise patients to obtain ALT/AST levels.

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