Terbinafine
LAMISIL
What it isAllylamine inhibiting squalene epoxidase; dermatophyte onychomycosis and tinea.
Why this oneFar higher cure rates in nail infection than topical agents or itraconazole, and it concentrates in keratin.
What limits itHepatotoxicity means baseline liver tests. It is a strong CYP2D6 inhibitor, which matters for metoprolol and tricyclics; taste loss can be permanent.
FDA-approved for
- onychomycosis (1996)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Fingernail onychomycosis | Adults | 250 mg QD | 250 mg QD × 6 weeks | 250 mg QD |
| Toenail onychomycosis | Adults | 250 mg QD | 250 mg QD × 12 weeks | 250 mg QD |
Renal Undefined
Hepatic Contraindicated in chronic or active liver disease
Instructions
- Evaluate for chronic/active liver disease and obtain baseline serum transaminases before starting; monitor LFTs periodically
- Take one 250 mg tablet once daily
- Discontinue if liver injury, taste/smell disturbance, or drug reaction develops
Contraindications
- Chronic or active liver disease
- History of allergic reaction to oral terbinafine (risk of anaphylaxis)
Cautions
- Hepatotoxicity / liver failure (may require transplant or be fatal) — monitor LFTs
- Taste and smell disturbance (may be severe, prolonged, or permanent)
- Depressive symptoms
- Severe neutropenia (discontinue if ANC ≤1000)
- Serious skin reactions: SJS, TEN, erythema multiforme, DRESS
Adverse reactions
- Headache, diarrhea, rash, dyspepsia, liver enzyme abnormalities, pruritus, taste disturbance, nausea, abdominal pain, flatulence
Pregnancy Postmarketing data insufficient; no fetal harm in animal studies
Lactation Present in human milk (oral)
NO BOXED WARNINGS
Principal riskHepatotoxicity; a strong CYP2D6 inhibitor
Cost, est. cash$10–$300/month
Generic entry2007
Classes and tags
Clinical profile
Legacy pregnancy categoryC
Defining liabilityLocal irritation or hypersensitivity; systemic toxicity is minimal with correct local use.
Mechanism of action: Terbinafine ballicule
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Strong CYP2D6 inHibitor
