Generic Name

Winlevi

Mechanism

• Target: Fungal leucyl‑tRNA synthetase (LeuRS).
• Action: Tavaborole forms a covalent complex with the enzyme’s tRNA‑binding site, halting the addition of leucine to the growing polypeptide chain.
• Result: Inhibition of fungal protein synthesis → impaired growth and eventual fungal eradication.
• Selectivity: Human LeuRS is not significantly inhibited at therapeutic concentrations, minimizing host toxicity.

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Pharmacokinetics

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Indications

• Primary Indication: Onychomycosis (≥ 5 fingernails or toenails) caused by dermatophytes (T. rubrum, T. interdigitale).
• FDA/EMA: 12‑month course (≈ 3–6 months of daily application, followed by additional 3‑month maintenance).
• Recommended Use: In patients with normal skin, adequate nail trimming, and no concomitant systemic immunosuppression.

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Contraindications

• Contraindications
• Hypersensitivity to tavaborole or any component of the gel.
• Active skin infections or open wounds over the nail bed.
• Warnings
• Allergic contact dermatitis: Rare but possible; discontinue if persistent erythema, itching, or vesiculation occurs.
• Limited data in pregnancy, lactation, or pediatric populations (≥ 12 yrs).
• Limited evidence of systemic safety in patients with severe renal impairment.
• Precautions
• Avoid application to broken skin or inflamed nails.
• Use gloves if known drug allergy occurs.

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Dosing

• Application: Thin layer (≈ 0.25 g) onto the affected nail(s) and surrounding peri‑nail skin once daily (preferable in the evening).
• Contact Time: Leave on nail for at least 5 min before washing or touching; longer exposure improves efficacy.
• Maintenance:
• Treatment phase: 1–6 months, depending on number and severity.
• Maintenance: 3 additional months (weekly or daily as per response).
• Technique:
• Trim nails short prior to first application.
• Use small nail clippers rather than harsh scissors to reduce trauma.

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Adverse Effects

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Monitoring

• Clinical response: Assess nail pigmentation, ridging, and penetration after 3 months.
• Adverse reaction: Monitor for dermatitis or systemic signs after each month.
• Laboratory: Not routinely needed; consider renal panel if prolonged systemic exposure suspected.
• Compliance: Evaluate patient’s adherence at each visit; adherence strongly correlates with cure rate.

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Clinical Pearls

1. Maximize Contact Time – Applying the gel immediately before bedtime increases nail penetration; remove any footwear or nail polish to avoid occlusion for hours.
2. Avoid Mechanical Trauma – Over‑trimming or aggressive filing can worsen fungal entry; use gentle clippers and keep nails short but not ragged.
3. Patch Test First – For patients with a history of allergic contact dermatitis, perform a 48‑hr patch test on the forearm before full application.
4. Combine With Oral Therapy if Needed – For extensive disease (> 5 nails or proximal nail matrix involvement), consider adjunctive oral terbinafine to shorten the course.
5. Educate on Foot Hygiene – Drier feet and footwear reduce reinfection; advise use of breathable socks and regular drying.
6. Long‑Term Follow-Up – Recurrence is common; re‑evaluate nails annually for early re‑treatment.
7. Labeling for Children – While labeled for adults, a small study showed safety in adolescents ≥ 12 yrs; monitor closely.

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