18456 Modeling of usage and estimation of cost for efinaconazole 10% topical solution in the treatment of onychomycosis

Abstract

Onychomycosis accounts for half of all nail diseases with toenails more commonly affected compared with fingernails. Efinaconazole 10% solution is often prescribed for toenail onychomycosis due to its higher mycologic and complete cure rates compared with other topicals. Cost is a limiting factor, with the average retail price for a 4-mL bottle being $575.49. Since the manufacturer has not reported the number of drops in a 4 or 8 mL bottle, it is unknown how much to prescribe for each patient and to estimate cost. We sought to calculate the volume of efinaconazole needed for a full treatment course and approximate cost by modeling patient usage. The length and width of all toenails were recorded from 26 volunteers and surface area was calculated. A 17 × 14 mm acrylic nail was affixed to a foot mannequin to reproduce the average female great toenail with 2-mm margins demarcated to replicate the nailfolds. One drop of efinaconazole 10% solution was applied to the surface of the great toenail and one drop was applied to the hyponychium. This process was repeated until the 4 mL bottle was depleted and then the experiment was replicated with a total of 5 bottles. Our study shows that there is large variability in the output volume of efinaconazole 10% solution. A 4 mL bottle lasts a mean of 24 days, and 2 drops is sufficient to treat 2 smaller toenails, which enables physicians to estimate volume and cost for a full onychomycosis treatment course.