Dermatophyte: Fingernails and Toenails - Antibiotic Prescribing

Doses are oral and for adults unless otherwise stated. Visit the Health Products Regulatory Authority (HPRA) website for detailed drug information (summary of product characteristics and patient information leaflets). Dosing details, contraindications and drug interactions can also be found in the Irish Medicines Formulary (IMF) or other reference sources such as British National Formulary (BNF) / BNF for children (BNFC). See guidance on dosing in children for quick reference dosage/weight guide. Refer to drug interactions table for detailed drug interactions for all antimicrobials. Note extensive drug interactions for clarithromycin, fluoroquinolones, azole antifungals and rifampicin. Many antibiotics increase the risk of bleeding with anticoagulants.

Note additional warnings for clarithromycin and fluoroquinolones

Comments from Expert Advisory Committee

  • Take nail clippings: Start therapy if infection is confirmed by laboratory.
  • Idiosyncratic liver reactions occur rarely with terbinafine. It is more effective than the azoles.
  • Itraconazole is also active against yeasts.
  • In non-dermatophyte moulds use itraconazole.C
  • For children seek specialist opinion




TX Duration

5% amorolfine nail lacquer B- (for superficial)


fingers 6 months toes 12 months


250 mg OD

fingers 6 – 12 weeks toes 3 – 6 months

second line: itraconazole 200 mg BD fingers 7 days monthly
(2 courses) toes 7 days monthly (3 courses)
  • Onychomycosis commoner in toenails than nails.
  • Baseline LFT's. Antifungals are associated with hepatoxicity rarely (idiosyncratic). Risk benefit discussion with the patient as cure rates range between only 20-50%
  • Take nail clippings and subungal debris for microscopy and culture. Exclude other nail disease.
  • 1st line: Terbinafine (preferred over Itraconazole) 250mgs od po 6/52 fingernails.
  • 12-16 weeks for toenails.
  • 1st line : Itraconazole 200mgs od po 12 weeks or a pulse dose 400mgs per day for one week per month. 2 pulses for fingernails and 3 pulse weeks for toenails.
  • 2nd line : Fluconazole 150-450mgs/week 3/12 fingernails and 6/12 toenails.
  • Griseofulvin: 500-1000mgs/day 6-9 months fingernails and 12-18months in toenails.
  • Amorolfine: 5% lacquer once or twice weekly for 6/12.

Reviewed June 2016