I have been on griseofulvin and itraconazole for six months but my infection has recurred; what is the next best management?

Switch to Terbinafine for Dermatophyte Onychomycosis

After 6 months of griseofulvin and itraconazole with recurrence, you should switch to oral terbinafine 250 mg daily for 12-16 weeks for toenails or 6 weeks for fingernails, as it demonstrates superior efficacy and lower relapse rates compared to both agents you've already tried. 1

Why Terbinafine is Your Best Option

The British Association of Dermatologists guidelines explicitly state that terbinafine is superior to both griseofulvin and itraconazole for dermatophyte onychomycosis 1. Here's the critical evidence:

• Cure rates: Terbinafine achieves 55% complete cure vs. 26% with pulsed itraconazole at 72 weeks 1
• Long-term success: At 5-year follow-up, 46% maintained mycological cure with terbinafine vs. only 13% with itraconazole 1
• Relapse rates: Significantly lower with terbinafine (23% clinical relapse) compared to itraconazole (48% clinical relapse) 1

Treatment Protocol

Dosing:

• Toenails: 250 mg daily for 12-16 weeks
• Fingernails: 250 mg daily for 6 weeks 1

Monitoring:

• Baseline liver function tests and complete blood count (especially if history of alcohol use, hepatitis, or hematological abnormalities) 1
• Re-evaluate at 3-6 months after treatment initiation 1
• Continue treatment if disease persists at re-evaluation 1

Why Your Previous Treatments Failed

Griseofulvin limitations:

• Only 30-40% mycological cure rates for toenail infections 1
• Weakly fungistatic (not fungicidal) 1
• No longer considered first-line due to lower efficacy 1

Itraconazole issues:

• Higher relapse rates (53% mycological relapse) 1
• Less effective than terbinafine in head-to-head trials 1

Critical Considerations Before Starting

1. Confirm the diagnosis: Ensure you have dermatophyte infection (not Candida or non-dermatophyte molds) through mycological testing, as terbinafine has lower activity against Candida 1

2. Rule out contraindications: Active or chronic liver disease is a contraindication 1

3. Warn about permanent taste disturbance: Though very rare, this can be permanent and patients must be informed 1

4. Consider combination therapy: Adding topical amorolfine or ciclopirox may improve outcomes, though evidence is limited 1

If Terbinafine Also Fails

Should terbinafine fail after adequate treatment duration:

1. Re-confirm mycology: Rule out non-dermatophyte molds (Scopulariopsis, Fusarium) which may require different agents 1

2. Consider fluconazole: 450 mg once weekly for at least 6 months for toenails, though less effective than terbinafine 1

3. Evaluate for drug resistance: Though rare, resistance patterns are emerging 1

4. Assess compliance and drug interactions: Terbinafine has minimal drug interactions, but absorption and compliance issues should be addressed 1

Common Pitfalls to Avoid

• Stopping treatment too early: The nail must be re-evaluated 3-6 months after starting therapy, not at the end of the treatment course 1
• Not obtaining baseline labs: Hepatotoxicity, though rare (0.04% serious adverse events), requires baseline monitoring in at-risk patients 1
• Ignoring the causative organism: If this is Candida or non-dermatophyte mold onychomycosis, terbinafine will not work—itraconazole would be preferred 1

The evidence strongly supports terbinafine as your next step, with the understanding that onychomycosis remains challenging to cure and may require extended follow-up beyond the treatment period.