It works by killing the fungus or preventing its growth. In deciding to use a medicine, the risks of using the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes. However, terbinafine has not been shown to cause birth defects or other problems in animal studies.
Oral terbinafine passes into breast milk.
It is not known whether topical terbinafine passes into breast milk. Although most medicines pass into breast milk in small amounts, many of them may be used safely while breast-feeding. Mothers who are using this medicine and who wish to breast-feed should discuss this with their doctor. Nursing mothers should not apply topical terbinafine to the breasts. Therefore, it may not be known whether they work exactly the same way they do in younger adults.