Onychomycosis (OM) is the most common cause of dystrophic nails, and it is responsible for up to 50% of cases. Apart from significantly damaging the nails, quality of life, and self‑image of the sufferer, it also acts as a reservoir of fungal infections carrying important implications for emerging recalcitrant dermatophytoses. Treatment of OM is based on guidelines released almost a decade back, in addition to published literature and personal preferences. Hence, an expert group of the Nail Society of India (NSI) worked towards drafting these guidelines aimed at compiling recommendations for the pharmacologic treatment of OM based on scientific evidence, along with practical experience.

Practice points/Recommendations

• Oral terbinafine should be the first-line therapy in dermatophytic OM, administered at a dose of 250 mg once a day.
  This should be done for 6 weeks for fingernails and 12 weeks for toenails. A continuous regimen should be preferred
  over a pulse or intermittent regimen. Liver function tests at baseline should be done only for patients in whom liver
  dysfunction is suspected or expected. They should be repeated if any symptoms or signs of liver involvement are noted
  on follow-up. The drug should be withdrawn if liver enzymes rise 3 times above the reference range.
• Itraconazole pulse therapy is recommended as first-line therapy in NDM OM, while dermatophyte OM is second-line therapy.
  2/3 pulses are recommended for fingernails and 3/4 pulses for toenails. It can also be used where the causative agent
  has not been confirmed, but the clinical setting suggests so. A baseline liver function test should be done for all
  patients. Periodic monitoring is needed only in patients with pre-existing liver disease. Improved formulations could
  be used in patients with gastrointestinal adverse effects or poor tolerance; however, efficacy needs to be proven in
  comparative trials.
• Terbinafine is recommended as the first-line treatment for onychomycosis (mostly caused by dermatophytes), with
  itraconazole being the alternative drug. Whereas itraconazole is the first-line drug in non-dermatophytic OM.
• Fluconazole is recommended as second-line therapy in individuals requiring systemic therapy, where terbinafine or
  itraconazole cannot be used. Weekly 150 mg for 6 months (fingernails) or 12 months (toenails) or longer may be used.
• Ciclopirox olamine 8% nail lacquer monotherapy is limited in efficacy and has low compliance rates; however, it could
  be considered with proper methodology for patients in whom topical therapy is indicated or systemic therapy is
  contraindicated.
• Once applied weekly, amorolfine lacquer can be used as monotherapy whenever topical therapy is indicated. The USFDA
  has not yet approved the drug, though it has been approved in Europe and Australia. It offers the advantage of better
  compliance and can also be used to prevent recurrences.
• Currently, there is low-level evidence to recommend or refute luliconazole therapy in OM. Future controlled studies
  can help assess its efficacy.
• Both efinaconazole and tavaborole are currently unavailable in India; however, as per available literature, they hold
  a promising future, especially in patients where systemic therapy is contraindicated and in the pediatric population.
• Combination therapy: Scientific evidence supporting the use of combination therapy with different classes of drugs
  has been shown to improve treatment outcomes. Thus, it is recommended in patients with indications for systemic therapy
  (GOR A). Both ciclopirox (GOR C) and amorolfine (GOR B) may be used for combination therapies; however, amorolfine has
  better evidence base and a convenient dosing schedule.
• Sequential therapy: Currently, there is low-level evidence to recommend or refute sequential therapy in OM.
• Booster therapy: Supplemental/booster therapy involves additional drug dosing, over and above the recommended course,
  to “boost” antifungal action. It is recommended to use booster therapy for patients with slow growth of nails, plate
  thickness >2 mm, involvement of lateral edge or >75% plate, matrix involvement, or immunosuppression.

Reference: Mahajan K, Grover C, Relhan V, et al. Nail Society of India (NSI) recommendations for pharmacologic therapy of onychomycosis. Indian Dermatol Online J. 2023;14(3):330–341.