Can oral antifungal therapy (terbinafine or itraconazole) be initiated for onychomycosis treatment given the patient's current elevated liver enzymes?

Oral Antifungal Therapy for Onychomycosis in Patients with Elevated Liver Enzymes

Oral antifungal therapy (terbinafine or itraconazole) should not be initiated until liver enzymes normalize, as both medications carry significant risk of hepatotoxicity in patients with pre-existing liver dysfunction. 1, 2

Assessment of Liver Function

• Baseline liver function tests are essential before starting oral antifungal therapy
• Terbinafine and itraconazole are both contraindicated in patients with active or chronic liver disease 1
• The FDA label explicitly states: "Terbinafine tablets are not recommended for patients with chronic or active liver disease" 1
• Hepatotoxicity can occur with both medications, potentially leading to:
  • Liver failure
  • Need for liver transplantation
  • Death 1, 3

Management Algorithm for Onychomycosis with Elevated Liver Enzymes

1. First step: Delay oral antifungal therapy until liver enzymes normalize 2
2. Monitor liver function: Repeat liver function tests in 2 weeks as planned
3. If liver enzymes normalize:
   • For dermatophyte onychomycosis: Terbinafine is first-line (250 mg daily for 6 weeks for fingernails, 12 weeks for toenails) 2, 1
   • For Candida onychomycosis: Itraconazole is first-line (200 mg daily or 400 mg pulse therapy) 4
4. If liver enzymes remain elevated:
   • Proceed with topical antifungal solutions as planned
   • Consider nail removal procedure as scheduled on 8/22/25

Monitoring During Treatment

If oral therapy is eventually initiated:

• Monitor liver function tests at 1,2, and 4 weeks after starting therapy, then every 3 months 4
• Immediately discontinue medication if:
  • Liver function tests become elevated
  • Patient develops symptoms of liver injury (nausea, anorexia, fatigue, vomiting, right upper abdominal pain, jaundice, dark urine, pale stools) 1

Topical Alternatives

If liver enzymes remain elevated, topical options include:

• Ciclopirox nail lacquer
• Amorolfine (where available)
• Efinaconazole
• Tavaborole

These have lower efficacy than oral agents but avoid systemic toxicity 4, 2

Surgical Approach

The scheduled bilateral hallux nail removal procedure (8/22/25) is a reasonable approach when:

• Oral antifungals are contraindicated
• Topical treatments have failed or are likely to fail
• The infection is severe or causing significant discomfort

Important Cautions

• Fatal hepatitis has been reported even with pulse itraconazole therapy for onychomycosis 3
• The risk of hepatotoxicity exists even in patients without pre-existing liver disease 1
• Both terbinafine and itraconazole can cause serious adverse effects beyond hepatotoxicity, including:
  • Taste/smell disturbances (can be permanent)
  • Serious skin reactions (Stevens-Johnson Syndrome)
  • Depressive symptoms 1, 2

Patient Education

Advise the patient to:

• Continue avoiding alcohol and hepatotoxic medications
• Report immediately any symptoms of liver injury
• Understand that even with successful treatment, visible nail improvement takes months due to the slow growth rate of nails 1