Is it safe to use terbinafine in a patient with mildly elevated liver enzymes?

Terbinafine Use in a Patient with Mildly Elevated Liver Enzymes

Terbinafine should be used with caution in this patient with mildly elevated liver enzymes (ALT 57 U/L, GGT 45 U/L), but is not absolutely contraindicated given the minimal elevation. 1, 2

Risk Assessment

The patient's liver function tests show:

• ALT: 57 U/L (slightly above reference range of <55)
• GGT: 45 U/L (slightly above reference range of <40)
• All other liver parameters are normal:
  • AST: 29 U/L (normal)
  • ALP: 89 U/L (normal)
  • Bilirubin: 8 umol/L (normal)
  • Albumin: 46 g/L (normal)

Safety Considerations

• Terbinafine carries a risk of hepatotoxicity that can occur in patients with and without pre-existing liver disease 1
• Cases of liver failure leading to transplant or death have been reported, with greater risk in those with active or chronic liver disease 1
• The FDA label states terbinafine "is not recommended for patients with chronic or active liver disease" 1

Recommended Approach

1. Baseline Assessment

   • Perform a thorough liver function assessment before initiating treatment 2
   • Document current mild elevations and establish this as the baseline

2. Treatment Protocol

   • If treatment is necessary, consider:
     • Using the lowest effective dose (250 mg daily)
     • Limiting treatment duration (6 weeks for fingernails, 12 weeks for toenails) 2
     • Consider topical alternatives if the infection is limited in scope

3. Monitoring Requirements

   • Monitor liver function tests at weeks 1,2, and 4 after starting therapy, then every 3 months 2
   • Immediately discontinue terbinafine if there is biochemical or clinical evidence of liver injury 1
   • Re-evaluate at 3-6 months to assess clinical response 2

4. Patient Education

   • Advise the patient to report immediately any symptoms of liver injury:
     • Persistent nausea
     • Anorexia
     • Fatigue
     • Vomiting
     • Right upper abdominal pain
     • Jaundice
     • Dark urine
     • Pale stools 1
   • Counsel on avoiding alcohol during treatment

Alternative Considerations

• For dermatophyte infections, terbinafine is more effective than itraconazole, but itraconazole may be considered if liver concerns increase 3
• For Candida infections, itraconazole is the first-line treatment 2
• Topical antifungals (ciclopirox, amorolfine) have lower efficacy but avoid systemic toxicity 2

Special Precautions

• The severity of hepatic events may be worse in patients with active or chronic liver disease 1
• Terbinafine should be immediately discontinued if liver function tests become significantly elevated 1
• Case reports have documented successful use of terbinafine in patients with stable liver disease when careful monitoring is implemented 4

While this patient's liver enzyme elevations are minimal, the potential for hepatotoxicity requires careful consideration of the risk-benefit ratio, appropriate monitoring, and patient education about warning signs of liver injury.