Dosing and uses of Lamisil (terbinafine)
Adult dosage forms and strengths
tablet
- 250mg
packet, oral granules
- 125mg
- 187.5mg
Onychomycosis
250 mg (1 tablet) PO daily for 6 weeks (fingernail) or 12 weeks (toenail)
Tinea Pedis (Off-label)
250 mg/day PO in single dose or divided q12hr for 2-6 weeks
Tinea Corporis, Tinea Cruris
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)
Dosing Modifications
Renal impairment: Use not recommended if CrCl <50 mL/min
Hepatic impairment: Use not recommended in chronic or active liver disease
Pediatric dosage forms and strengths
tablet
- 250mg
packet, oral granules
- 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
Lamisil (terbinafine) adverse (side) 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
Warnings
Contraindications
Hypersensitivity
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
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
Pregnancy and lactation
Pregnancy category: B
Lactation: Drug excreted in breast milk; do not use
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 of Lamisil (terbinafine)
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%)
