Does Lamisil (terbinafine) affect renal function?

Terbinafine (Lamisil) and Renal Function

Yes, terbinafine can affect renal function and is contraindicated in patients with renal impairment according to the British Association of Dermatologists' guidelines. 1

Renal Considerations with Terbinafine

• Terbinafine is primarily cleared by the kidneys, and its clearance is decreased in patients with severe kidney disease 2
• The British Association of Dermatologists explicitly lists renal impairment as a contraindication for terbinafine use 1
• Patients with reduced renal function may experience drug accumulation, potentially leading to increased risk of adverse effects 3

Documented Renal Effects

• Case reports have documented severe adverse renal outcomes with terbinafine use, including:
  • Rhabdomyolysis leading to acute kidney injury requiring hemodialysis 4
  • Drug-induced lupus erythematosus with progression to lupus nephritis 5

Monitoring Recommendations

• Baseline assessment of renal function should be performed before initiating terbinafine therapy 2
• In patients with pre-existing renal disease, alternative antifungal medications should be considered 1
• Fluconazole is also contraindicated in renal impairment, but itraconazole may be a better alternative in patients with renal issues but normal hepatic function 1

Pharmacokinetic Considerations

• Unlike some medications where dose adjustments can compensate for reduced renal function, terbinafine is specifically contraindicated rather than recommended for adjusted dosing 1
• The drug's long half-life and persistence in nail tissue for up to 30 weeks after treatment completion may contribute to prolonged exposure in patients with impaired renal clearance 6

Clinical Implications

• For patients requiring antifungal therapy who have renal impairment, topical treatments like amorolfine or ciclopirox may be safer alternatives 1
• Patients on terbinafine should be monitored for signs of renal dysfunction, including changes in urination patterns, edema, or unexplained fatigue 4, 5
• If renal dysfunction develops during terbinafine treatment, the medication should be discontinued immediately 4

Terbinafine remains a first-line treatment for dermatophyte onychomycosis in patients with normal renal function, but its use requires careful consideration of renal status before initiation 1, 6.