What Is Terbinafine and How Does It Work?

Terbinafine is an antifungal antibiotic used to treat infections caused by fungus that affect the fingernails or toenails (onychomycosis). Oral granules are used to treat a fungal infection of scalp hair follicles in children who are at least 4 years old.

  • Terbinafine is available under the following different brand names: Lamisil.

What Are Dosages of Terbinafine?

Dosages of Terbinafine:

Adult and Pediatric Dosage Forms and Strengths


  • 250 mg

Packet, oral granules

  • 125 mg
  • 187.5 mg
Dosage Considerations – Should be Given as Follows:


Tinea Pedis (Off-label)

  • 250 mg/day orally in a single dose or divided every 12 hours for 2-6 weeks

Tinea Corporis, Tinea Cruris

  • 250 mg/day orally in a single dose or divided every 12 hours for 2-4 week

Sporotrichosis, Lymphocutaneous and cutaneous (Off-label)

  • 500 mg/day orally every 12 hours for 2-6 weeks; treat for additional 2-4 weeks after resolution of all lesions (resolution may take 3-6 months)

Tinea Capitis, Pediatric

  • Children over 4 years (less than 25 kg): 125 mg/day orally for 6 weeks
  • Children over 4 years (25-35 kg): 187.5 mg/day orally for 6 weeks
  • Children over 4 years (greater than 35 kg): 250 mg/day orally for 6 weeks

Dosing Modifications

  • Renal impairment: Use not recommended if CrCl is less than 50 mL/min
  • Hepatic impairment: Use contraindicated in chronic or active liver disease

What Are Side Effects Associated with Using Terbinafine?

Common side effects of terbinafine include:

  • Headache
  • Skin rash
  • Itching
  • Nausea
  • Diarrhea
  • Indigestion
  • Abdominal/stomach pain
  • Stomach upset
  • Elevated liver function test results
  • Visual disturbance
  • Gas
  • Dizziness
  • Spinning sensation
  • Temporary unusual or unpleasant taste or loss of taste in your mouth

Serious side effects of terbinafine include:

  • Persistent nausea
  • Loss of appetite
  • Fatigue
  • Vomiting
  • Right upper abdominal pain
  • Yellowing skin and eyes (jaundice)
  • Dark urine
  • Pale stools
  • Smell disturbance

Postmarketing side effects of terbinafine reported include:

This is not a complete list of side effects and other serious side effects may occur. Call your doctor for information and medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What Other Drugs Interact with Terbinafine?

If your doctor has directed you to use this medication for your condition, your doctor or pharmacist may already be aware of any possible drug interactions or side effects and may be monitoring you for them. Do not start, stop, or change the dosage of this medicine or any medicine before getting further information from your doctor, healthcare provider, or pharmacist first.

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist. Check with your physician if you have health questions or concerns.

What Are Warnings and Precautions for Terbinafine?


This medication contains terbinafine. Do not take Lamisil if you are allergic to terbinafine or any ingredients contained in this drug.

Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center immediately.


  • Hypersensitivity
  • Chronic or active liver disease

Effects of Drug Abuse

  • No information available

Short-Term Effects

  • See "What Are Side Effects Associated with Using Terbinafine?"

Long-Term Effects

  • See "What Are Side Effects Associated with Using Terbinafine?"


  • Discontinue if the following develop: Liver disease, neutropenia (absolute neutrophil count less than 1000 mcL); skin rash; signs or symptoms of systemic lupus erythematosus (SLE)
  • Changes in ocular lens and retina reported; may require discontinuation of therapy
  • Use caution in renal and liver impairment
  • Periodic monitoring of liver function tests is recommended
  • Ask patients and caregivers to report immediately to the healthcare provider any symptoms or signs of persistent nausea, loss of appetite, fatigue, vomiting, right upper abdominal pain or yes slowing skin and eyes (jaundice), dark urine, or pale stools; if these symptoms occur discontinue taking oral terbinafine, and immediately evaluate patient's liver function
  • Serious skin/hypersensitivity reactions (e.g., Stevens-Johnson Syndrome, toxic epidermal necrolysis, and drug reaction with eosinophilia and systemic symptoms [DRESS] syndrome); manifestations of DRESS syndrome may include cutaneous reaction (e.g., rash, exfoliative dermatitis), eosinophilia, and 1 or more organ complications (e.g., hepatitis, pneumonitis, nephritis, myocarditis, pericarditis)
  • Due to potential toxicity, confirmation of onychomycosis or dermatomycosis recommended
  • Smell disturbance reported; discontinue therapy if symptoms occur
  • CYP2D6 inhibitor; may also convert CYP2D6 extensive metabolizers to poor metabolizer status
  • Cases of thrombotic microangiopathy (TMA), including thrombotic thrombocytopenic purpura and hemolytic uremic syndrome, some fatal, reported with terbinafine; discontinue terbinafine if clinical symptoms and laboratory findings consistent with TMA occur; the findings of unexplained thrombocytopenia and anemia should prompt further evaluation and consideration of the diagnosis of TMA

Pregnancy and Lactation

  • Terbinafine use during pregnancy may be acceptable. Either animal studies show no risk but human studies are not available or animal studies showed minor risks and human studies were done and showed no risk.
  • Terbinafine is excreted in breast milk; do not use it if breastfeeding.

Medscape. Terbinafine Side Effects Center.
RxList. Lamisil Side Effects Center.

Health Solutions From Our Sponsors