Eddie asked
My big toe nail is white and brittle. It looks exactly like the images showing digital subungual onychomycosis. I have been applying Kerydin 5% for a year with zero change. Should I try an over the counter drug like Lamisil or Lotrimin? Thank you
Answer
Unfortunately, over the counter topical anti-fungal products, like Lamisil and Lotrimin, rarely work to successfully treat onychomycosis (fungal nail infection). They act locally and poorly penetrate the nail plate and therefore cannot reach the site of infection.
In fact, fungal nail infections are notoriously hard to treat. Even oral systemic therapies have less than a 50% cure rate. We wrote an article discussing various fungal nail infection treatments, which can be found here: Oral therapies for nail infections. Topical prescription products, such as Penlac and Jublia are even less effective (but may be safer in terms of adverse reactions).
Over the counter fungal products, which include Lamisil (terbinafine), Lotrimin (clotrimazole) and Fungi-Nail (undecylenic Acid) are only recommended (and indicated) to treat athlete’s foot and fungus around the nail, not in and under it.
There are some studies that indicate non-conventional therapies may help, which include applying Vicks VapoRub or using 100% tea tree oil. These therapies may be worthwhile to try, but evidence is minimal and certainly aren't as efficacious as prescription therapy.
Lastly, it is important to know that Lamisil (terbinafine) is both an over the counter topical cream and oral tablet available by prescription. When it comes to treating fungal nail infections, the oral tablet is the one that is indicated for that use.
Be sure to see your doctor for an appropriate diagnosis and treatment plan.
