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Home > Drug Category > Anti-Fungal > Lamisil 1% and Equivalent

Lamisil 1% (Terbinafine) Information

Lamisil 1% (terbinafine), an allylamine derivative, is used as a highly effective topical antifungal agent. It is available over-the-counter (OTC) and is primarily indicated for treating common superficial fungal infections of the skin, including tinea pedis (athlete's foot), tinea cruris (jock itch), tinea corporis (ringworm), and pityriasis versicolor. Lamisil 1% is typically formulated as a cream, gel, or spray and is applied directly to the affected and surrounding skin areas, usually once or twice daily. Due to its fungicidal properties and its ability to persist in the skin, topical Lamisil often has a shorter treatment duration—1 week for athlete's foot with specific formulations (like gels or sprays), or 1 to 4 weeks with the cream—compared to other topical antifungals. However, treatment should be continued for the whole recommended period to prevent recurrence.

The mechanism of action for terbinafine is fungicidal (killing) and highly specific to the fungal cell. Terbinafine works by selectively inhibiting the enzyme squalene epoxidase, which is a crucial enzyme early in the biosynthesis pathway of ergosterol—the essential structural component of the fungal cell membrane. By inhibiting this enzyme, terbinafine prevents the production of ergosterol. It simultaneously causes a toxic buildup of squalene within the fungal cell. This accumulation of squalene severely impairs the cell membrane's function and structure, leading to cell lysis and fungal death. Because Lamisil 1% is used topically, the amount of terbinafine absorbed systemically is minimal.

Lamisil 1% Side Effects

As a topical application, Lamisil 1% side effects are generally confined to the area of treatment. Common side effects are localized, mild, and often temporary, including application site reactions such as stinging, burning, irritation, and redness (erythema). Other frequent, but mild, reactions can involve dryness, flaking, or scaling of the skin, and mild localized itching (pruritus). These symptoms usually resolve shortly after application or as the skin adjusts to the treatment.

However, more serious side effects can occur, although they are scarce due to the minimal systemic absorption of the topical formulation. If any of the following symptoms are experienced, the patient should stop applying the medication and seek immediate medical attention:

• Allergic Contact Dermatitis: A delayed hypersensitivity reaction characterized by an intense, spreading rash, severe redness, blistering, or acute inflammation at the site of application.

• Hypersensitivity/Systemic Allergic Reaction: Though infrequent with the topical formulation, systemic allergic reactions may occur. Symptoms include severe swelling of the face, tongue, or throat, dizziness, and difficulty breathing.

• Severe Skin Reactions: In rare cases, severe cutaneous reactions, such as blistering, peeling, or ulceration, have been reported; these are primarily associated with the oral formulation but should prompt immediate medical attention if they manifest with topical use.

Lamisil 1% Precautions

Lamisil 1% (terbinafine) is for external use on the skin only and should not be used in the mouth, eyes, or vagina. If accidental eye contact occurs, the eyes should be thoroughly rinsed with running water. Patients should be advised to wash their hands thoroughly after using the bathroom to prevent the spread of infection to other areas of the body or to different people. For formulations containing alcohol (sprays or gels), the product is flammable. It should be kept away from heat, open flames, and sources of ignition. If there is no improvement in the skin condition after the whole recommended treatment period, or if the rash worsens, the diagnosis should be reassessed by a healthcare professional. Although Lamisil is highly effective, the treatment's success depends on reducing conditions that promote fungal growth; therefore, the affected area should be kept clean and dry. When applying the cream to the groin area, it should be noted that the non-medicinal ingredients may damage latex condoms and diaphragms, reducing their effectiveness. The cream is generally not recommended for use on children unless advised by a doctor. The long-term safety of topical Lamisil during pregnancy and breastfeeding has not been definitively established, and consultation with a doctor is recommended.

Do I need a prescription to order Lamisil 1%?

No, a prescription is not required from your physician to order Lamisil 1%.