Function

• Lamisil works by preventing fungal cells from producing a lipid called ergosterol needed for proper cell functioning. Without ergosterol, fungal cells begin to die, eliminating the infection.
  
  

Uses

• Lamisil is primarily used to treat a fungal infection known as onychomycosis, which affects your fingernails and toenails.
  
  

Time Frame

• For fingernail infections, doctors typically prescribe 250 mg of Lamisil once daily for six week, while toenail infections require 250 mg daily for 12 weeks, according to RxList.com.
  
  

Risks

• The most common side effects of Lamisil include muscle aches, stomach pain and nasal congestion. Lamisil has the potential to cause liver damage as well as potentially fatal skin conditions such as Stevens-Johnson Syndrome.
  
  

Considerations

• Because animal studies revealed that the drug has the potential to cause harmful effects upon fetal development, doctors rarely prescribe Lamisil for pregnant women, explains RxList.com. If you have a history of alcoholism, blood problems, lupus and kidney or liver disease, it may not be safe for you to take Lamisil due to its potential side effects, warns the Mayo Clinic.