Antifungal Regimens for Onychomycosis

Drug	Fingernails	Toenails	Notes
Terbinafine	250 mg PO once daily × 6 weeks	250 mg PO once daily × 12 weeks	First-line for dermatophytes. Check baseline LFTs.
Itraconazole (continuous)	200 mg PO once daily × 6 weeks OR 100 mg PO BID × 6 weeks (off-label)	200 mg PO once daily × 12 weeks OR 100 mg PO BID × 12 weeks	Effective but higher drug–drug interactions.
Itraconazole (pulse)	200 mg PO BID × 1 week per month, repeat × 2 months	200 mg PO BID × 1 week per month, repeat × 3–4 months	Preferred when avoiding long continuous therapy.
Fluconazole (off-label)	150–300 mg PO weekly × 3 - 6 months	150–300 mg PO weekly × 6 - 12 months	Alternatively, a slower cure rate, especially for Candida.
Topical: Ciclopirox 8% lacquer	Apply daily × 24 weeks	Apply daily × 48 weeks	Only if <50% nail plate is involved, no matrix disease.
Topical: Efinaconazole 10% solution	Apply daily × 24 weeks	Apply daily × 48 weeks	Better efficacy than ciclopirox but costly.

✅ Key Takeaways for Exams & Practice

Terbinafine PO = first-line (most effective, shortest duration) ✅
Toenails require longer treatment (12 weeks) due to slow nail growth
Itraconazole pulse therapy = alternative option (useful in compliance issues or contraindication to terbinafine)
Topical therapy = only for mild disease (<50% nail, no matrix involvement)
Always check LFT before systemic antifungals and monitor if prolonged use

🦠 Why Onychomycosis Occurs

Onychomycosis = fungal infection of the nail plate + nail bed + matrix

Common organisms

Dermatophytes (MOST COMMON) → Trichophyton rubrum
Non-dermatophyte molds → Scopulariopsis
Candida → more common in fingernails

Risk factors

Elderly (↓ nail growth, ↓ immunity)
Diabetes mellitus / peripheral vascular disease
Immunosuppression (HIV, chemo, steroids)
Chronic moisture (farmers, swimmers, housekeepers)
Repeated trauma
Tinea pedis (important source!)

🔍 Clinical Features

Nail discoloration (yellow / brown / white)
Thickened, brittle nail
Onycholysis
Subungual debris
Toenails > fingernails (moist + slow growth)

🏥 Management of Onychomycosis

✅ Setting: OPD

Most cases treated outpatient
Admit only if severe immunocompromise or complication

1. Definitive Treatment

🔥 First-line (EXAM MUST REMEMBER)

👉 Terbinafine (250 mg) 1×1 po pc

Fingernail: 6 weeks
Toenail: 12 weeks ✔️ Fungicidal against dermatophytes ✔️ Recommended by AAD / IDSA

🟣 Alternative: Itraconazole

Continuous therapy

👉 Itraconazole (100 mg) 1×2 po pc for 12 weeks (toenail) OR 👉 Itraconazole (200 mg) 1×1 po pc for 12 weeks

⭐ Pulse therapy (HIGH-YIELD)

👉 Itraconazole (100 mg) 2×2 po pc for 1 week/month

Fingernail: 2 cycles
Toenail: 3–4 cycles

🟡 Alternative (less preferred)

👉 Fluconazole (150–300 mg) 1×1 weekly po for several months

Useful in Candida

🧴 Topical (ONLY mild cases)

Ciclopirox 8% daily × 48 weeks
Efinaconazole 10% daily × 48 weeks
Amorolfine 5% lacquer

❌ NOT for severe or matrix involvement

2. Supportive Treatment

Keep nails short, clean, and dry
Avoid tight shoes / moisture
Treat tinea pedis👉 Terbinafine cream (1%) 1×1 topical for 2–4 weeks
Avoid trauma
Educate: long treatment + recurrence risk

3. Monitoring & Complications

✅ Baseline LFT before systemic therapy
Repeat if >6 weeks or symptomatic

Side effects:

Hepatotoxicity (important!)
GI upset
Rash

Complications:

Nail deformity
Secondary bacterial infection (esp. diabetic)

4. Follow-up

Clinical cure assessed at 6–12 months
Reinforce prevention:
- Keep feet dry
- Antifungal powder
- Treat contacts

📌 Exam Pearls (VERY HIGH-YIELD)

✅ Terbinafine = drug of choice for dermatophyte toenail infection
✅ Itraconazole = broader spectrum (Candida, non-dermatophytes)
❌ Steroids are NOT used → worsen fungal infection
❗ Toenail = always longer treatment (12 weeks or pulse cycles)

Antifungal Regimens for Onychomycosis: Drug Choices, Dosing, and Practical Pearls (Fungi, Fungus)