More proximal or extensive disease

• for more proximal or extensive onychomycosis topical treatments are unlikely to be effective and systemic treatment should be considered
  
  
• the systemic treatment of choice is Terbinafine 250mg daily. This should be continued for between 6 weeks and 3 months in fingernail infection, or for 3 to 6 months in toenail onychomycosis (1). Further cultures might be taken at 3 months to assess the necessity for prolonged treatment. In cases of toenail dystrophy a nail paint may also be added in. The success of treatment is of cure in 80-95% of cases. Terbinafine interacts with relatively few other drugs and is generally well tolerated
  
  
• alternative systemic treatments for dermatophyte onychomycosis include
  • Itraconazole as pulsed therapy - 200mg twice daily for 1 week a month for 2 months in fingernail and for 3 months in toenail infections
  • Griseofulvin 10mg/kg/daily for 6-9 months in fingernail infection or 15-18 months for toenails (no longer considered as a treatment option for dermatophyte infections)

Reference:

• (1) Health Protection Agency 2009. Fungal nail & skin infections: diagnosis & laboratory investigation – Quick reference guide for primary care
• (2) Roberts DT, Taylor WD, Boyle J. Guidelines for treatment of onychomycosis. British Journal of Dermatology 2003;148:402–410
• (3) Public Health England 2017. Fungal skin and nail infections: Diagnosis and laboratory investigation - Quick reference guide for primary care.