Dermatopharmacology and Topical Therapy Flashcards

What is the mechanism of action of terbinafine (Lamisil) in treating onychomycosis?

Answer: Inhibits squalene epoxidase, blocking ergosterol synthesis and causing toxic squalene accumulation

Terbinafine inhibits squalene epoxidase, an earlier step in ergosterol synthesis, causing dual toxicity — ergosterol depletion and accumulation of toxic squalene within the fungal cell.

Photosensitivity reactions are a known adverse effect of which commonly prescribed antibiotic used for acne?

Answer: Doxycycline

Doxycycline, a tetracycline antibiotic widely used for inflammatory acne, commonly causes phototoxic reactions — patients must be counseled to use broad-spectrum sunscreen and avoid prolonged sun exposure.

Which topical therapy is first-line treatment for molluscum contagiosum in immunocompetent children?

Answer: Watchful waiting or cantharidin application

Molluscum contagiosum in immunocompetent children typically self-resolves; if treatment is desired, cantharidin (blister beetle extract) or watchful waiting are preferred approaches.

Crisaborole (Eucrisa) is a topical PDE4 inhibitor approved for which condition?

Answer: Mild-to-moderate atopic dermatitis in patients ≥3 months

Crisaborole inhibits phosphodiesterase-4 (PDE4), reducing cAMP breakdown and subsequent inflammatory cytokine production, and is approved for mild-to-moderate atopic dermatitis.

What is the role of niacinamide (nicotinamide) in topical skin care and dermatology?

Answer: Reduces transepidermal water loss, decreases sebum production, and inhibits melanosome transfer

Topical niacinamide improves the skin barrier by increasing ceramide synthesis, reduces TEWL, decreases sebum production, and inhibits melanosome transfer from melanocytes to keratinocytes.

Ivermectin 1% cream is approved for topical treatment of which skin condition?

Answer: Rosacea (papulopustular subtype)

Topical ivermectin 1% cream (Soolantra) is FDA-approved for inflammatory lesions of rosacea, working through anti-inflammatory effects and reduction of Demodex mite burden.