SOLTERB 250

Terbinafine is an allylamine antifungal that inhibits fungal ergosterol synthesis at an earlier step than the triazole antifungals, targeting squalene epoxidase rather than lanosterol demethylase. Squalene epoxidase catalyses the first oxygenation step in the ergosterol biosynthesis pathway — converting squalene to squalene epoxide. Terbinafine's inhibition of this enzyme has two fungicidal consequences: firstly, ergosterol depletion disrupts fungal membrane structure and function; secondly, the resulting accumulation of squalene itself is directly toxic to the fungal cell, causing intracellular lipid accumulation, vacuolisation, and membrane disruption.

This dual consequence — ergosterol depletion AND squalene accumulation — makes terbinafine fungicidal rather than merely fungistatic against dermatophytes, in contrast to the predominantly fungistatic azoles. Fungicidal activity is particularly clinically important for onychomycosis, where the high inoculum of fungal elements in nail plate requires complete organism killing rather than growth suppression.

Terbinafine's spectrum is narrower but more potent than azoles for its primary targets: dermatophytes (Trichophyton rubrum, T. mentagrophytes, Microsporum canis, Epidermophyton floccosum) — the organisms responsible for the vast majority of onychomycosis, tinea pedis, tinea corporis, and tinea capitis. Against Candida, terbinafine is fungistatic only, and its activity against non-dermatophyte moulds is variable.

The lipophilicity of terbinafine enables exceptional keratinophilic tissue distribution — it accumulates at concentrations 10–100 times higher than plasma in nail, skin, and sebaceous gland secretions, where dermatophytes reside. Nail concentrations persist at therapeutic levels for 6–12 months after completion of a 12-week course — the pharmacological basis for the relatively short oral course achieving complete nail cure.

SOLTERB 250 is indicated for dermatophytic infections where oral therapy is required — either due to infection extent, nail involvement, or failure of topical antifungal treatment.

Onychomycosis (Primary Indication): Terbinafine 250mg daily for 6 weeks (fingernails) or 12 weeks (toenails) is the guideline-recommended first-line treatment for dermatophytic onychomycosis — achieving mycological cure rates of 70–80% at 12 weeks, superior to itraconazole pulse therapy. The 20×7 blister (140 tablets per box) supports the full 12-week toenail course at 250mg daily.

Tinea Capitis: Terbinafine 250mg daily for 4 weeks is preferred over griseofulvin for Trichophyton-caused tinea capitis (the dominant species in Asia and Africa) — it achieves higher cure rates in 4 weeks versus the 6–8 weeks required with griseofulvin.

Tinea Corporis and Tinea Cruris: 250mg daily for 2–4 weeks for widespread or recalcitrant dermatophytosis unresponsive to topical therapy. In the context of the Indian epidemic of multi-drug-resistant tinea (including tinea unguium and corporis resistant to itraconazole, fluconazole, and terbinafine at standard doses), higher doses (500mg) or longer courses may be required under specialist guidance.

Tinea Pedis: 250mg daily for 2 weeks for plantar tinea pedis.

Pityriasis Versicolor: Off-label but effective for Malassezia infections resistant to topical therapy.

Dosage and administration should be as prescribed by a qualified doctor or medical professional. Do not self-medicate. Always follow your physician's instructions regarding dose, frequency and duration of treatment.