What is the next step in treating my onychomycosis (toenail fungus) given my liver function test results are pending?

Treatment for Onychomycosis with Pending Liver Function Tests

The next step in treating your toenail fungus is to wait for your liver function test results before starting oral antifungal medication, as these tests are essential to determine if you can safely take systemic therapy. 1

Why Liver Function Tests Are Required

Oral antifungal medications, particularly terbinafine (the first-line treatment for toenail fungus), require liver function testing before initiation because:

• Cases of liver failure have occurred with terbinafine use, some leading to liver transplant or death 2
• Hepatotoxicity may occur in patients with and without pre-existing liver disease 2
• The British Association of Dermatologists and American Academy of Dermatology both recommend baseline liver function tests before starting oral antifungal therapy 3, 1

Treatment Algorithm Based on Liver Function Results

If Liver Function Tests Are Normal:

1. First-line treatment: Oral terbinafine 250mg daily for 12 weeks for toenail infection 1, 2

   • Most effective option with 73-94% mycological cure rate 1
   • Shorter treatment duration than alternatives 3

2. Second-line treatment (if terbinafine cannot be tolerated):

   • Itraconazole 200mg daily for 12 weeks continuously, or as "pulse therapy" at 400mg daily for 1 week per month for 3 months 3, 1
   • Fluconazole 150-450mg weekly for at least 6 months 3, 1

If Liver Function Tests Are Abnormal:

1. Topical treatments should be considered instead:

   • Efinaconazole 10% solution (mycological cure rates of 50%) 1, 4
   • Amorolfine 5% nail lacquer (approximately 50% efficacy in distal nail infections) 3, 1
   • Ciclopirox 8% lacquer (mycological cure rates of 34%) 1, 5

2. Mechanical approaches:

   • Nail debridement combined with topical therapy can improve treatment response 5
   • For severe cases, partial nail removal plus antifungal therapy may be considered 1

Monitoring During Treatment

• If prescribed terbinafine, periodic monitoring of liver function is recommended 2
• Immediately report any symptoms of liver problems (persistent nausea, anorexia, fatigue, vomiting, right upper abdominal pain, jaundice, dark urine, or pale stools) 2
• Be aware of potential side effects such as taste disturbance, smell disturbance, or depressive symptoms 2

Prevention of Recurrence

To prevent recurrence (which happens in 40-70% of cases) 1:

• Keep nails short and clean
• Dry feet well after bathing
• Wear cotton socks and change them daily
• Apply antifungal powders to shoes and feet
• Avoid sharing nail clippers
• Wear protective footwear in public areas
• Consider discarding old footwear or treating it with antifungal solutions 3

Important Considerations

• Onychomycosis treatment requires patience as visible improvement takes time - optimal clinical effect is seen some months after completing treatment 2
• Untreated onychomycosis can cause pain, discomfort, and physical impairment, negatively impacting quality of life 5
• The diagnosis should be confirmed through laboratory testing (KOH preparation, fungal culture, or nail biopsy) before starting treatment 2

While waiting for your liver function test results, you can begin implementing preventive measures and consider consulting with your provider about nail debridement to prepare for treatment.