Dosing & Uses
Dosage Forms & Strengths
tablet
- 250mg
packet, oral granules (discontinued)
- 125mg
- 187.5mg
Onychomycosis
Indicated for onychomycosis of the toenail or fingernail owing to dermatophytes (tinea unguium
250 mg (1 tablet) PO daily for 6 weeks (fingernail) or 12 weeks (toenail)
Dosage Modifications
Renal impairment: Use not recommended if CrCl <50 mL/min
Hepatic impairment: Use contraindicated in chronic or active liver disease
Tinea Pedis (Off-label)
250 mg/day PO in single dose or divided q12hr for 2-6 weeks
Tinea Corporis, Tinea Cruris (Off-label)
250 mg/day PO in single dose or divided q12hr for 2-4 weeks
Sporotrichosis, Lymphocutaneous and cutaneous (Off-label)
500 mg/day PO q12hr for 2-6 weeks; treat for additional 2-4 weeks after resolution of all lesions (resolution may take 3-6 months)
Dosage Forms & Strengths
tablet
- 250mg
packet, oral granules (discontinued)
- 125mg
- 187.5mg
Tinea Capitis
≥4 years (<25 kg): 125 mg/day PO for 6 weeks
≥4 years (25-35 kg): 187.5 mg/day PO for 6 weeks
≥4 years (>35 kg): 250 mg/day PO for 6 weeks
Interactions
Interaction Checker
No Results

Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor

Adverse Effects
>10%
Headache (13%)
1-10%
Rash (6%)
Pruritus (3%)
Nausea (3%)
Diarrhea (6%)
Dyspepsia (4%)
Abdominal pain (2%)
Taste disturbance (3%)
Elevated liver function test results (3%)
Visual disturbance (1%)
Postmarketing Reports
Idiosyncratic and symptomatic hepatic injury; more rarely, cases of liver failure, some leading to death or liver transplant
Skin and subcutaneous tissue disorders (eg, Stevens-Johnson Syndrome and toxic epidermal necrolysis), drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome
Anaphylaxis, angioedema
Severe neutropenia, thrombocytopenia, agranulocytosis, pancytopenia, anemia
Psoriasiform eruptions or exacerbation of psoriasis, acute generalized exanthematous pustulosis, precipitation and exacerbation of cutaneous and systemic lupus erythematosus
Taste and smell disturbances
Malaise, fatigue, vomiting, arthralgia, myalgia, rhabdomyolysis, reduced visual acuity, visual field defect, hair loss, serum sickness-like reaction, vasculitis, pancreatitis, influenzalike illness, pyrexia, increased blood creatine phosphokinase, photosensitivity reactions
Hearing impairment, vertigo
Thrombotic microangiopathy (TMA), including thrombotic thrombocytopenic purpura and hemolytic uremic syndrome
Warnings
Contraindications
Hypersensitivity
Chronic or active liver disease
Cautions
Discontinue if the following develop: Liver disease, neutropenia (absolute neutrophil count <1000 mcL); skin rash; signs or symptoms of SLE
Changes in ocular lens and retina reported; may require discontinuation of therapy
Use caution in renal and liver impairment
Periodic monitoring of liver function tests is recommended
Ask patients and caregivers to report immediately to healthcare provider any symptoms or signs of persistent nausea, anorexia, fatigue, vomiting, right upper abdominal pain or jaundice, dark urine, or pale stools; if these symptoms occur discontinue taking oral terbinafine, and immediately evaluate patient’s liver function
Serious skin/hypersensitivity reactions (eg, Stevens-Johnson Syndrome, toxic epidermal necrolysis, and drug reaction with eosinophilia and systemic symptoms [DRESS] syndrome); manifestations of DRESS syndrome may include cutaneous reaction (eg, rash, exfoliative dermatitis), eosinophilia, and 1 or more organ complications (eg, hepatitis, pneumonitis, nephritis, myocarditis, pericarditis)
Due to potential toxicity, confirmation of onychomycosis or dermatomycosis recommended
Smell disturbance reported; discontinue therapy if symptoms occur
CYP2D6 inhibitor; may also convert CYP2D6 extensive metabolizers to poor metabolizer status
Cases of thrombotic microangiopathy (TMA), including thrombotic thrombocytopenic purpura and hemolytic uremic syndrome, some fatal, reported with terbinafine; discontinue terbinafine if clinical symptoms and laboratory findings consistent with TMA occur; the findings of unexplained thrombocytopenia and anemia should prompt further evaluation and consideration of diagnosis of TMA
Pregnancy & Lactation
Pregnancy
Available data from postmarketing cases in pregnant women are insufficient to evaluate drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes
Animal data
- In animal reproduction studies, the drug did not cause malformations or any harm to fetus when administered to pregnant rabbits and rats during period of organogenesis at oral doses up to 12 and 23 times the maximum recommended human dose (MRHD) of 250 mg/day, respectively
Because treatment of onychomycosis can be postponed until after pregnancy is completed, it is recommended that oral terbinafine not be initiated during pregnancy
Lactation
After oral administration, terbinafine is present in human milk; however, there are no data on effects on breastfed child or on milk production; developmental and health benefits of breastfeeding should be considered along with mother’s clinical need for therapy; tablets and any potential adverse effects on breastfed child from therapy or from underlying maternal condition
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Inhibits squalene epoxidase, reducing cell membrane ergosterol synthesis, causing inhibition of fungal cell-wall synthesis and subsequently fungal cell death
Absorption
Absorption >70%
Bioavailability: 40% (Adults); 36-64% (children)
Peak plasma time: 1-2 hr
Peak plasma concentration (250-mg dose): 1 mcg/mL
Distribution
Predominantly distributed to sebum and skin
Protein bound: >99%
Vd: 2000 L
Metabolism
Metabolized in liver by several CYP450 enzymes; first-pass effect (40%)
Metabolites: Inactive
Enzymes inhibited: CYP2D6
Elimination
Half-life: 36 hr (drug released very slowly from skin and adipose tissues)
Excretion: Urine (~70%)
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Formulary
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