Lamisil: Clinically Proven Antifungal Treatment for Onychomycosis
Lamisil (terbinafine hydrochloride) is a leading oral and topical antifungal medication indicated for the treatment of dermatophyte infections, most notably onychomycosis of the toenail or fingernail. As a member of the allylamine class of antifungals, it works by inhibiting squalene epoxidase, a key enzyme in ergosterol synthesis, thereby disrupting fungal cell membrane integrity. With over three decades of clinical use and extensive research supporting its efficacy and safety profile, Lamisil remains a first-line therapeutic choice for healthcare providers managing fungal infections. Its systemic formulation offers superior mycological cure rates compared to many topical alternatives, particularly for moderate to severe cases.
Features
- Contains terbinafine hydrochloride as the active pharmaceutical ingredient
- Available in 250 mg oral tablets and 1% topical formulations (cream, solution, spray)
- Exhibits fungicidal activity against dermatophytes such as Trichophyton species
- Demonstrated bioavailability of approximately 70-80% when administered orally
- Topical formulations designed for enhanced skin and nail penetration
- Manufactured under strict pharmaceutical quality control standards
Benefits
- Achieves complete mycological cure in majority of patients with dermatophyte infections
- Prevents recurrence of fungal nail infections through comprehensive eradication
- Reduces nail discoloration, thickening, and dystrophy associated with onychomycosis
- Minimizes risk of secondary bacterial infections through restoration of skin barrier integrity
- Offers convenient once-daily dosing regimen for improved patient adherence
- Provides rapid symptomatic relief with visible improvement often within weeks
Common use
Lamisil is primarily prescribed for the treatment of onychomycosis of toenails or fingernails caused by dermatophyte fungi (tinea unguium). It is also indicated for tinea corporis (ringworm), tinea cruris (jock itch), tinea pedis (athlete’s foot), and tinea versicolor when caused by susceptible organisms. The oral formulation is particularly effective for moderate to severe nail infections where topical penetration may be insufficient, while topical formulations are preferred for superficial skin infections or as adjunctive therapy.
Dosage and direction
Oral tablets: The standard adult dosage for onychomycosis is 250 mg once daily. Treatment duration typically ranges from 6 weeks for fingernail infections to 12 weeks for toenail infections. Take with or without food, preferably at the same time each day.
Topical formulations: Apply a thin layer to affected area once or twice daily, depending on formulation and infection severity. For nail infections, ensure thorough cleaning and drying before application. Gently rub into affected nail and surrounding skin.
Continue treatment for the full prescribed duration even if symptoms improve earlier to prevent recurrence. Laboratory monitoring may be recommended during extended therapy.
Precautions
- Complete blood counts should be monitored during treatment periods exceeding 6 weeks
- Hepatic enzyme levels should be assessed baseline and during therapy in patients with pre-existing liver conditions
- Use with caution in patients with renal impairment (creatinine clearance less than 50 mL/min)
- Not recommended for patients with chronic or active liver disease
- May cause taste disturbance that usually resolves upon discontinuation
- Photosensitivity reactions have been reported with topical application
- Discontinue if progressive skin rash occurs
Contraindications
- Hypersensitivity to terbinafine or any component of the formulation
- Severe hepatic impairment (Child-Pugh Class C)
- Chronic or active liver disease
- History of drug-induced liver injury
- Pregnancy and breastfeeding (oral formulation)
- Concurrent use with specific CYP2D6 substrates with narrow therapeutic index
Possible side effect
Common (≥1/100): Headache, gastrointestinal disturbances (nausea, diarrhea, dyspepsia), taste disturbance, rash, pruritus
Uncommon (≥1/1000): Elevation of liver enzymes, visual disturbances, dizziness, fatigue
Rare (<1/1000): Severe skin reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis), hepatobiliary dysfunction, blood dyscrasias (neutropenia, agranulocytosis), depression, anxiety
Topical applications: Local irritation, burning sensation, erythema, dryness at application site
Drug interaction
- Potent inhibitors of CYP2D6 may increase terbinafine concentrations
- May reduce metabolism of CYP2D6 substrates (beta-blockers, SSRIs, TCAs, antiarrhythmics)
- Rifampin and other CYP inducers may decrease terbinafine concentrations
- Cimetidine may increase terbinafine bioavailability
- Potential interaction with warfarin (monitor INR)
- May affect caffeine metabolism
Missed dose
If a dose is missed, take it as soon as remembered unless it is nearly time for the next scheduled dose. Do not double the dose to make up for a missed one. Maintain regular dosing schedule to ensure consistent therapeutic levels. For topical formulations, apply when remembered and resume regular schedule.
Overdose
Symptoms may include nausea, vomiting, abdominal pain, dizziness, rash, and frequent urination. In case of suspected overdose, seek immediate medical attention. Supportive care is recommended, including gastric lavage if presented within one hour of ingestion. Activated charcoal may be administered. No specific antidote exists; hemodialysis is unlikely to be beneficial due to high protein binding.
Storage
Store at room temperature (15-30°C or 59-86°F) in original container. Protect from light and moisture. Keep topical formulations tightly closed when not in use. Do not freeze. Keep all medications out of reach of children and pets. Do not use beyond expiration date printed on packaging.
Disclaimer
This information is provided for educational purposes only and does not constitute medical advice. Individual response to medication may vary. Consult a healthcare professional for proper diagnosis and treatment recommendations. Do not initiate or discontinue medication without medical supervision. Full prescribing information should be reviewed before use.
Reviews
“After struggling with onychomycosis for years, Lamisil tablets provided complete clearance. Required regular monitoring but achieved permanent results where topicals had failed.” - Dermatology Patient, 54
“As a podiatrist, I prescribe terbinafine as first-line treatment for confirmed dermatophyte onychomycosis. The cure rates consistently outperform topical alternatives in moderate to severe cases.” - Dr. Evans, DPM
“Topical Lamisil solution worked effectively for my fingernail infection without systemic side effects. Application requires consistency but avoided need for oral medication.” - Pharmacy Customer, 38
“Clinical studies demonstrate mycological cure rates of 70-85% with oral terbinafine versus 5-15% with vehicle in placebo-controlled trials. remains gold standard treatment.” - Clinical Study Summary