Terbinafine belongs to the class of medications called antifungals. It is used to treat certain types of fungal infections of the skin and nails.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The recommended adult dose is 250 mg once daily. If you have reduced liver or kidney function, your doctor may recommend a lower dose. The length of treatment depends on the condition being treated and the severity of the infection.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones given here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed. Use the medication for the prescribed length of time even if the infection clears up, to prevent it from coming back. If you miss a dose, take it as soon as you remember. If it is the following day before you remember your next dose, skip the missed dose and resume your usual dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.

Do not take this medication if you:

• are allergic to terbinafine or any ingredients of the medication
• have long-term or active liver disease

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

Tablets:

• bloating or feeling of fullness in the stomach
• diarrhea
• headache
• heartburn
• increased sensitivity to the sun
• loss of appetite
• nausea
• stomach pain (mild)

Cream, spray:

• burning
• dryness
• flaking or peeling skin
• itching
• other signs of skin irritation not present before use of this medication
• peeling
• rash
• redness
• scabs
• skin discoloration
• skin lesions
• stinging
• tingling

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

Tablets:

• aching joints and muscles
• changes in sense of taste lasting for several days
• change of taste or loss of taste
• fever
• hearing changes
• signs of anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
• signs of depression (e.g., poor concentration, changes in weight, changes in sleep, decreased interest in activities, thoughts of suicide)
• signs of muscle breakdown (e.g., discoloured urine, unexpected muscle pain, aches)
• skin rash or itching
• symptoms of blood disorders (such as sore throat, fever, chills, mouth sores, or unusual bleeding or bruising)
• symptoms of liver problems (such as unusual fatigue, yellow eyes or skin, abdominal pain, dark urine, pale stools, itching, or loss of appetite)
• vision changes
• weight loss

Stop taking the medication and seek immediate medical attention if any of the following occur:

• signs of pancreatitis (e.g., abdominal pain on the upper left side, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen)
• symptoms of a serious allergic reaction (such as hives, difficulty breathing, or swelling of the face or throat)
• symptoms of a serious skin rash (such as redness, blistering, peeling, or loosening of skin)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Blood counts: This medication may decrease the number of neutrophils (a type of white blood cell that helps fight infection), red blood cells (which carry oxygen), and platelets (which help your blood to clot). Your doctor will do blood tests to monitor this. If you notice any signs of infection (e.g., fever, chills, or sore throat) or unusual bleeding or bruising, contact your doctor immediately.

Depression: Rarely, this medication has been reported to cause mood swings and symptoms of depression. If you have depression or a history of depression or anxiety, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. If you experience symptoms of depression such as poor concentration, changes in weight, changes in sleep, decreased interest in activities, or notice them in a family member who is taking this medication contact your doctor as soon as possible.

External use only: Terbinafine cream and spray are for external use only. Avoid contact with the eyes. Do not use the spray on the face. In case of accidental contact with the eyes, rinse eyes thoroughly with running water and consult a doctor if any symptoms persist. In case of inhalation, contact a doctor if any symptoms develop and persist. Topical forms of terbinafine are not effective for treating fungal infections of the nails.

Kidney function: The safety and effectiveness of using terbinafine have not been determined for people with decreased kidney function. The kidneys are partially responsible for removing terbinafine from the body. Decreased kidney function may cause terbinafine to build up in the body causing side effects. If you have decreased kidney function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Liver function: Terbinafine tablets are not recommended for people with chronic (long-term) or active liver disease. Decreased liver function can cause terbinafine to build up in the body, causing side effects including further liver damage. Your doctor may order liver function tests before you start and while you are taking terbinafine tablets. During treatment with terbinafine, report to your doctor any signs or symptoms of liver problems including unusual fatigue, loss of appetite, yellowing of skin or eyes, abdominal pain, nausea and vomiting, dark urine, pale stools, or itching.

Lupus erythematosus: Occasionally, people taking terbinafine report a flare-up of systemic lupus erythematosus (SLE). If you have SLE, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Sensory disturbances: People taking terbinafine occasionally experience changes in how they sense things. Vision changes, difficulty hearing, a decreased sense of touch, change in the sense of taste or loss of smell have all been reported. If you notice changes while you are taking this medication, contact your doctor.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: This medication passes into breast milk. If you are a breast-feeding mother and are taking terbinafine, it may affect your baby. Women taking terbinafine tablets should not breast-feed. If you are using the cream or spray, talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children.

There may be an interaction between terbinafine and any of the following:

• amiodarone
• amphetamines (e.g., dextroamphetamine, lisdexamfetamine)
• antipsychotic medications (e.g., chlorpromazine, clozapine, haloperidol, olanzapine, quetiapine, risperidone)
• atomoxetine
• azole antifungals (e.g., fluconazole, itraconazole, ketoconazole)
• beta-adrenergic blockers (e.g., atenolol, propranolol, sotalol)
• codeine
• cyclosporine
• dextromethorphan
• doxepin
• doxorubicin
• eliglustat
• flecainide
• MAO inhibitors type B (e.g., maprotiline, selegiline)
• metoclopramide
• propafenone
• rifampin
• Saccharomyces boulardii
• selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, fluoxetine, paroxetine, sertraline)
• tamoxifen
• tamsulosin
• tetrabenazine
• tramadol
• tricyclic antidepressants (e.g., amitriptyline, desipramine)

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.