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Terbinafine is used to treat fungal nail infections. The most common side effects are a headache, diarrhea, an upset stomach, itching, nausea, and gas. Terbinafine can make you sensitive to the sun. If you need to be in sunlight, wear sunscreen, a hat, and clothing that covers your skin. Stop this medicine and call your health care provider right away if you get nausea that will not go away, have a rash, taste changes, or smell changes.

Uses

What is terbinafine used for?

Terbinafine is commonly used to treat fungal nail infections (also known as onychomycosis or tinea unguium).

Terbinafine may also be used for other conditions as determined by your health care provider.

Terbinafine is also available in a topical form that is applied to the skin. See Terbinafine topical for more information.

How does terbinafine work (mechanism of action)?

Terbinafine is an antifungal medicine that stops certain types of fungi from growing and kills them by disrupting their cell structure.

How is terbinafine supplied (dosage forms)?

Brands and other names

  • Lamisil

Dosage forms and strengths

  • 250 mg oral tablets

How should I store terbinafine?

Terbinafine should be stored at room temperature, between 68 F and 77 F (20 C and 25 C). It can be exposed to temperatures between 59 F and 86 F (15 C and 30 C) for shorter periods of time, such as when you’re transporting it. Store it in a cool, dry place. Keep the tablets in a tightly closed container away from light.

Side Effects

What are the most common side effects of terbinafine?

The most common side effects of terbinafine are listed below. Tell your health care provider if you have any of these side effects that bother you.

  • Headache
  • Diarrhea
  • Rash
  • Nausea, upset stomach, or stomach pain
  • Itching
  • Change in how things taste (see below)
  • Gas
  • Abnormal liver function tests

There may be other side effects of terbinafine that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of terbinafine?

While less common, the most serious side effects of terbinafine are described below, along with what to do if they happen.

Severe Allergic Reactions. Terbinafine may cause allergic reactions, including a specific type of allergic reaction called DRESS. DRESS stands for drug reaction with eosinophilia and systemic symptoms. It is also sometimes called multi-organ hypersensitivity. This is a reaction that can affect multiple parts of the body, including your liver, kidneys, and heart. Stop taking the medicine and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Shortness of breath, trouble swallowing, or throat tightness
  • Swelling in your feet, ankles, or legs
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain
  • Dark-colored pee
  • Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Liver Damage. Liver damage, also called hepatotoxicity, can happen when taking terbinafine. Keep all appointments, including lab work, while you are taking this medicine. Call your health care provider right away if you have any of the following symptoms of liver damage.

  • Nausea or vomiting
  • Stomach or belly pain
  • Fever
  • Weakness or unusual tiredness
  • Itching
  • Loss of appetite
  • Light-colored poop
  • Dark-colored urine (pee)
  • Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Change in How Things Taste or Smell. Terbinafine can cause changes in how things taste or smell. These may lead to loss of taste and smell and be severe enough to cause anxiety or a depressed mood. Loss of taste or smell can be permanent. Stop taking terbinafine and call your health care provider right away if you notice any changes in your sense of taste or smell, have a poor appetite, or lose weight.

Depressed Mood. Terbinafine may cause depressive mood changes. Tell your health care provider if you notice any new or increased feelings of anxiety, depression, feeling sad or worthless, or other unusual changes in your mood or behavior. Also, tell your health care provider if you have changes in your sleep pattern, energy level, or interest in your usual activities. 

Blood Disorders. Terbinafine may cause low lymphocyte (lymphopenia or lymphocytopenia) or neutrophil (neutropenia) levels. These are types of white blood cells that help prevent infection. Having a low level of lymphocytes or neutrophils may increase your risk of infection. Tell your health care provider if you have any of the following symptoms.

  • Fever, chills, or sweats
  • Tiredness
  • Sore throat, coughing, or shortness of breath
  • Mouth or throat sores
  • Swollen lymph nodes

Severe Skin Reactions. Terbinafine can cause severe skin reactions, called Stevens-Johnson syndrome (SJS), erythema multiforme, and toxic epidermal necrolysis (TEN), that can lead to death if not treated. If you get a rash, stop terbinafine and call your health care provider right away. Get emergency help if you have any of the following symptoms of SJS or TEN.

  • Painful red or purple skin that looks burned and peels off
  • A flat red rash or blisters on your skin, mouth, nose, and genitals
  • Red, painful, watery eyes
  • Flu-like symptoms, including a fever, chills, and muscle aches

Lupus. Terbinafine can cause or worsen a condition called lupus. Stop taking terbinafine and call your health care provider right away if you have any of the following symptoms.

  • A rash that is scaly, red, or has a loss of skin color, and may be scarring
  • Unusual sun sensitivity that can cause a rash

Thrombotic Microangiopathy (TMA). Terbinafine can cause a serious problem with blood clotting. One type causes blood clots to form in some parts of your bloodstream, which causes a loss of platelets in the rest of the blood (thrombocytopenia). Another type can cause destruction of your red blood cells (which can cause anemia) or damage your organs, such as kidneys. TMA needs to be treated right away in the hospital or it can lead to death. Get emergency help if you have any of the following symptoms without another explanation.

  • Fever
  • Shortness of breath
  • Pale or yellowish skin
  • Your skin or the whites of your eyes turning yellowish in color (also called jaundice)
  • Changes in your vision
  • Unusual weakness or tiredness
  • Unexplained bruising or bleeding
  • Headache, confusion, or slurred speech
  • Fast heartbeat
  • Purplish spots (purpura) on the skin or in the mouth due to bleeding under the skin
  • Low amount of pee, or pee that is pink or has blood in it

Warnings & Precautions

Who should not use terbinafine?

Allergies to Ingredients. People who are allergic to any of the following should not take terbinafine.

  • Terbinafine
  • Lamisil
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific terbinafine products they stock.

Liver Problems. Terbinafine should not be used if your liver is not working as well as it should be. If there is a concern about the health of your liver, your health care provider may do tests to find out if it is working well enough to take this medicine.

What should I know about terbinafine before using it?

Do not take terbinafine unless it has been prescribed to you by a health care provider. Take it as prescribed.

Do not share terbinafine with other people, even if they have the same condition as you. It may harm them.

Keep terbinafine out of the reach of children.

Terbinafine can make your skin more sensitive to light from the sun, sunlamps, and tanning beds. This is called photosensitivity. Exposure to this light can cause severe sunburns, blisters, and swelling. If you need to be in sunlight, wear sunscreen, a hat, and clothing that covers your skin.

You may not be able to see the full effect of terbinafine until months after your last dose. This is because it takes time for a healthy nail to grow back. Talk to your health care provider if you have concerns.

What should I tell my health care provider before using terbinafine?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if terbinafine is right for you.

In particular, make sure that you discuss any of the following.

Other Medicines and Supplements. Terbinafine may interact with other medicines and supplements. Before using terbinafine, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

  • Liver problems
  • Problems with immune system
  • Lupus 

Pregnancy. It is not known if or how terbinafine could affect pregnancy or harm an unborn baby. Tell your health care provider if you plan to become pregnant. If you become pregnant while taking terbinafine, tell your health care provider right away.

Breastfeeding. Terbinafine passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will let you know if you should take terbinafine while breastfeeding.

Interactions

Does terbinafine interact with foods or drinks?

There are no known interactions between terbinafine and foods. Terbinafine slows down your body’s removal of caffeine, so the effects of caffeine from coffee or caffeinated drinks could last longer.

It is unknown if drinking alcohol will affect terbinafine, but both terbinafine and alcohol can cause liver damage. Heavy drinking can slow your immune response and make it harder for your body to fight infection. It is best to limit the amount of alcohol you drink. 

Does terbinafine interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking terbinafine.

  • A tricyclic antidepressant, such as amitriptyline, desipramine, nortriptyline, or protriptyline, even if it is not used for depression
  • A selective serotonin reuptake inhibitor (SSRI), such as fluoxetine, paroxetine, or sertraline, which is a medicine commonly used for anxiety and depression
  • A beta-blocker, such as atenolol (Tenormin), metoprolol (Lopressor, Toprol XL, and others), or propranolol (Inderal LA, Innopran XL), which is a medicine that may be used for certain heart conditions or to lower blood pressure
  • A selective monoamine oxidase B (MAO-B) inhibitor, such as rasagiline or selegiline, which is a medicine usually used for depression or Parkinson’s disease
  • Fluconazole (Diflucan), which is a medicine used for fungal infections
  • Warfarin, which is a blood thinner
  • Rifampin (Rifadin), which is a medicine commonly used to treat an infection called tuberculosis

Many other medicines may alter the blood levels of terbinafine, and vice versa. Tell your health care provider about all medicines that you take or have recently taken.

This may not be a complete list of medicines that can interact with terbinafine. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much terbinafine?

If you or someone else has used too much terbinafine, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of terbinafine?

If you miss a dose, take it as soon as you remember. If it is less than four hours before the next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.