Lamisil Spray (Terbinafine Hydrochloride)

Terbinafine is an allylamine antifungal that targets dermatophyte infections of the skin.

• Athlete's foot (tinea pedis): Reduces fungal growth, relieving itching, scaling and redness.
• Ringworm (tinea corporis): Clears the infection and promotes healing of skin lesions.
• Jock itch (tinea cruris): Eliminates the causative fungus and eases discomfort.

• Terbinafine inhibits the fungal enzyme squalene epoxidase, a key step in the biosynthesis of ergosterol, an essential component of fungal cell membranes. Blockade of this pathway leads to accumulation of squalene, which is toxic to the fungus, and depletion of ergosterol, causing loss of membrane integrity and ultimately fungal cell death. The selective inhibition is largely confined to fungal cells, resulting in minimal systemic toxicity when applied topically.

Terbinafine spray may cause local skin reactions and, rarely, systemic adverse events.

Common Side Effects

• Skin irritation: mild burning or stinging at the application site.
• Itching: transient pruritus around the treated area.
• Redness: localized erythema.
• Dryness: flaking or peeling of the skin.
• Contact dermatitis: allergic skin reaction.

Serious or Rare Side Effects

• Severe allergic reaction: swelling, hives, or difficulty breathing.
• Stevens‑Johnson syndrome: extensive skin blistering and detachment.
• Liver enzyme elevation: abnormal hepatic function tests.
• Urticaria: widespread hives.
• Systemic toxicity: rare systemic effects if large areas are treated.

Before using Lamisil Spray, consider the following safety precautions.

• Pregnancy: safety not established; consult a healthcare professional before use.
• Breastfeeding: unknown safety; use only if benefits outweigh potential risks.
• Age: not recommended for children under 2 years unless directed by a clinician.
• Open wounds: avoid application on broken skin, cuts or abrasions.
• Eyes and mucous membranes: do not apply near eyes, mouth or genital mucosa.
• Store at room temperature: keep in original container, protect from moisture and heat.

Terbinafine spray has limited systemic absorption, but potential drug interactions should be considered.

Major Interactions (Avoid)

• Systemic antifungal agents (e.g., itraconazole, ketoconazole): concurrent use may increase risk of hepatotoxicity.
• CYP2D6 substrates (e.g., certain antidepressants, antipsychotics): terbinafine can inhibit CYP2D6, potentially raising plasma levels of these drugs.

Moderate Interactions (Monitor Closely)

• Hepatotoxic drugs (e.g., isoniazid, methotrexate): monitor liver function if extensive skin areas are treated.
• Warfarin: rare reports of altered INR; monitor coagulation parameters.
• Topical corticosteroids: may increase skin irritation when used together.