Lamisil Dermgel (Terbinafine)

Lamisil Dermgel (terbinafine) is a topical allylamine antifungal indicated for the treatment of common superficial dermatophyte infections of the skin.

• Tinea pedis (athlete's foot): Reduces itching, scaling and redness on the feet, clears the dermatophyte infection, prevents further spread, and promotes healing of the affected skin.
• Tinea corporis (ringworm): Eliminates the expanding, ring‑shaped lesions on the trunk or limbs, relieves inflammation, halts fungal growth, and reduces associated discomfort.
• Tinea cruris (jock itch): Relieves irritation, redness and maceration in the groin area, resolves the fungal infection, improves comfort during daily activities, and helps prevent recurrence.

• Terbinafine inhibits the fungal enzyme squalene epoxidase, a key step in the ergosterol biosynthesis pathway. By blocking this enzyme, the drug prevents the formation of ergosterol, an essential component of fungal cell membranes, leading to accumulation of squalene, which is toxic to the fungus and results in cell death. The inhibition is selective for fungal enzymes, sparing human cells, and the effect is concentration‑dependent, providing a fungicidal action at the site of application.

Topical terbinafine may cause local skin reactions and, rarely, systemic adverse events.

Common Side Effects

• Burning sensation: A transient feeling of heat or stinging at the site of application, usually resolving without intervention.
• Itching: Mild pruritus that may develop during treatment and typically subsides with continued use.
• Redness: Localized erythema around the treated area, often mild and temporary.
• Dryness: The skin may become dry, flaky or slightly rough during therapy.

Serious or Rare Side Effects

• Severe allergic reaction: Includes swelling of the face, lips, tongue, hives, or difficulty breathing and requires immediate medical attention.
• Contact dermatitis: Persistent rash, blistering or intense irritation at the application site that does not improve with continued use.
• Systemic toxicity: Rare occurrences of liver enzyme elevations, hematologic abnormalities or severe skin reactions such as Stevens‑Johnson syndrome.

When using Lamisil Dermgel, certain precautions should be observed to ensure safety and effectiveness.

• Avoid application on broken skin: Do not apply to open wounds, cuts or abrasions.
• Limit use to indicated areas: Apply only to the affected skin regions diagnosed with fungal infection.
• Monitor for allergic response: Discontinue use and seek medical advice if signs of severe irritation develop.
• Use as directed: Follow the prescriber’s instructions regarding frequency and duration of treatment.
• Keep away from eyes: Prevent gel from contacting the eyes; rinse thoroughly if accidental exposure occurs.
• Store at room temperature: Keep below 25°C in the original packaging, protected from moisture and direct sunlight.

Topical terbinafine has a low potential for drug interactions, but certain substances may affect its safety or efficacy.

Major Interactions (Avoid)

• Concurrent use of systemic antifungal agents (e.g., oral terbinafine or itraconazole): May increase overall antifungal exposure and raise the risk of systemic toxicity.
• Strong CYP450 enzyme inhibitors taken orally (such as ketoconazole or erythromycin): Could elevate terbinafine plasma concentrations if any systemic absorption occurs.

Moderate Interactions (Monitor Closely)

• Excessive alcohol consumption during treatment: May exacerbate liver‑related adverse effects and should be limited to reduce hepatic stress.
• Application of other topical skin products (e.g., moisturizers, corticosteroid creams) over the same area: May alter terbinafine absorption or increase the chance of local irritation.
• Use of phototoxic agents or prolonged sun exposure while using the gel: May increase risk of skin photosensitivity.