Lamisil (Terbinafine Hydrochloride)

Lamisil is an oral allylamine antifungal indicated for infections caused by dermatophytes and related fungi.

• Onychomycosis: eradicates the fungal pathogen within the nail plate, promoting normal nail growth.
• Tinea pedis (athlete's foot): relieves itching and clears the infection on the feet.
• Tinea corporis (ringworm): eliminates the fungal lesion on the body’s skin.
• Tinea cruris (jock itch): resolves the infection in the groin area and reduces discomfort.

• Terbinafine inhibits the fungal enzyme squalene epoxidase, a key step in ergosterol synthesis. By blocking this pathway, the drug causes accumulation of squalene and depletion of ergosterol, disrupting fungal cell membrane integrity and leading to cell death without affecting human cholesterol synthesis.

Common Side Effects

• Gastrointestinal upset: nausea, abdominal pain or dyspepsia.
• Headache: mild to moderate intensity.
• Skin reactions: rash, pruritus or mild erythema.
• Altered taste: dysgeusia or loss of taste sensation.
• Elevated liver enzymes: mild, transient increases.

Serious or Rare Side Effects

• Hepatotoxicity: hepatitis, jaundice or liver failure.
• Severe cutaneous reactions: Stevens‑Johnson syndrome or toxic epidermal necrolysis.
• Hematologic abnormalities: neutropenia, agranulocytosis or eosinophilia.
• Peripheral neuropathy: numbness or tingling in extremities.
• Anaphylaxis: rare, potentially life‑threatening allergic response.

Before initiating therapy, consider the following precautions:

• Assess liver function: obtain baseline hepatic enzymes and monitor periodically.
• Monitor for skin reactions: discontinue if severe rash or blistering develops.
• Avoid use in known hypersensitivity: do not prescribe to patients with documented allergy to terbinafine or other allylamines.
• Review concomitant medications: evaluate for potential drug‑drug interactions.
• Use with caution in renal impairment: adjust dosing if required.
• Store at ambient temperature: keep in the original packaging, protect from moisture and heat.

Terbinafine may interact with several medicines, requiring careful management.

Major Interactions (Avoid)

• Itraconazole: combined use can increase risk of hepatotoxicity.
• Cimetidine: may raise terbinafine plasma levels.
• CYP2D6 inhibitors (e.g., quinidine): can elevate terbinafine concentrations.

Moderate Interactions (Monitor Closely)

• Alcohol: may exacerbate liver enzyme elevations.
• Warfarin: monitor INR for potential anticoagulant effect changes.
• Rifampin: may reduce terbinafine efficacy by inducing metabolism.