Terbinafine

Allylamine antifungal for treating skin and nail fungal infections

OTC – Topical Rx – Tablets ATC: D01BA02 Antifungal
Active Ingredient
Terbinafine hydrochloride
Available Forms
Cream, Gel, Tablet, Cutaneous solution
Common Strengths
10 mg/g, 1%, 98 mg/ml, 250 mg
Known Brands
Lamisil, Terbisil, Terclara, Terbinafin Teva
Medically reviewed | Last reviewed: | Evidence level: 1A
Terbinafine is a potent allylamine antifungal medication that kills fungi by disrupting their cell membranes. It is one of the most widely used treatments for dermatophyte infections of the skin and nails. Topical terbinafine (cream, gel, cutaneous solution) is available over-the-counter for athlete’s foot, jock itch and ringworm, while oral terbinafine tablets require a prescription and are the gold standard treatment for fungal nail infections (onychomycosis).
📅 Published:
📅 Reviewed:
Reading time: 16 minutes
Written and reviewed by iMedic Medical Editorial Team | Specialists in clinical pharmacology and dermatology

Quick Facts: Terbinafine

Active Ingredient
Terbinafine HCl
Drug Class
Allylamine Antifungal
ATC Code
D01BA02
Common Uses
Athlete’s Foot, Nail Fungus
Available Forms
Cream, Gel, Tablet, Solution
Prescription Status
OTC (topical) / Rx (oral)

Key Takeaways

  • Terbinafine is a powerful fungicidal antifungal that kills dermatophytes rather than merely inhibiting their growth, making it highly effective for skin and nail infections.
  • Topical terbinafine cream for athlete’s foot between the toes requires only one application daily for one week, making it one of the shortest treatment courses available.
  • Oral terbinafine is the first-line treatment for fungal toenail infections (onychomycosis), typically taken as 250 mg daily for 6–12 weeks for fingernails or 12–16 weeks for toenails.
  • Topical formulations (cream, gel, cutaneous solution) are available over-the-counter in most countries, while oral tablets require a prescription due to potential liver effects.
  • Liver function monitoring is recommended before and during oral terbinafine treatment; stop the medication and contact your doctor immediately if you develop signs of liver problems such as jaundice, dark urine, or persistent nausea.

What Is Terbinafine and What Is It Used For?

Quick answer: Terbinafine is an allylamine antifungal medication used to treat fungal infections of the skin (athlete’s foot, jock itch, ringworm) and nails (onychomycosis). It works by blocking an enzyme called squalene epoxidase in the fungal cell, leading to accumulation of squalene and deficiency of ergosterol, which disrupts the fungal cell membrane and kills the fungus.

Terbinafine belongs to the allylamine class of antifungal drugs and is one of the most commonly prescribed antifungal medications worldwide. It was first approved for medical use in the early 1990s and is listed on the World Health Organization’s Model List of Essential Medicines, reflecting its importance in global healthcare. Terbinafine is particularly effective against dermatophytes — the group of fungi responsible for the vast majority of skin, hair and nail infections in humans.

The mechanism of action of terbinafine is distinct from that of azole antifungals (such as fluconazole or clotrimazole). While azoles inhibit the later steps of ergosterol synthesis, terbinafine blocks the enzyme squalene epoxidase at an earlier stage. This dual effect — toxic accumulation of squalene combined with ergosterol deficiency — makes terbinafine fungicidal (it kills fungi) rather than merely fungistatic (inhibiting growth). This fungicidal property contributes to shorter treatment courses and lower relapse rates compared to many other antifungal agents.

Terbinafine is available in several formulations to suit different clinical needs. Topical preparations (cream at 10 mg/g or 1%, gel, and cutaneous solution at 98 mg/ml) are designed for superficial skin infections and are available without a prescription in most countries. Oral tablets (250 mg) are used for deeper or more resistant infections, particularly nail infections (onychomycosis), and require a doctor’s prescription because of the need for liver function monitoring during treatment.

Common uses of terbinafine

Terbinafine is indicated for a range of fungal infections, depending on the formulation used:

  • Athlete’s foot (tinea pedis): The most common use for topical terbinafine. The cream or gel is applied once daily for one week for infections between the toes, or for two weeks for infections on the sole or side of the foot.
  • Jock itch (tinea cruris): Fungal infection of the groin area, including infections caused by Candida species. Topical terbinafine is applied once daily for one to two weeks.
  • Ringworm (tinea corporis): Fungal infection of the body skin. Treated with topical terbinafine for one to two weeks.
  • Fungal nail infections (onychomycosis): The primary indication for oral terbinafine tablets. It is the most effective oral treatment for dermatophyte nail infections, with cure rates of 70–80% according to systematic reviews.
  • Cutaneous candidiasis: Skin infections caused by Candida species can be treated with topical terbinafine, although azole antifungals are sometimes preferred for these infections.

Topical terbinafine is not suitable for treating fungal nail infections. If you suspect a nail infection (for example, thickening, discolouration, or crumbling of the nail), you should consult your doctor, as oral treatment is usually required for effective treatment of nail mycosis.

What Should You Know Before Using Terbinafine?

Quick answer: Do not use terbinafine if you are allergic to terbinafine or any of the excipients. Avoid contact with the eyes when using topical formulations. Do not use during pregnancy or while breastfeeding without medical advice. Oral terbinafine requires liver function monitoring and should be used with caution in patients with pre-existing liver or kidney disease.

Contraindications

You should not use terbinafine in any form if you have a known allergy (hypersensitivity) to terbinafine hydrochloride or to any of the other ingredients in the particular formulation. Allergic reactions may manifest as rash, itching, hives, or in severe cases, swelling of the face and difficulty breathing. If you have experienced an allergic reaction to terbinafine in the past, you must inform your doctor or pharmacist before using any product containing this active ingredient.

Oral terbinafine is contraindicated in patients with chronic or active liver disease. Serious hepatotoxicity, including rare cases of liver failure leading to liver transplantation or death, has been reported with oral terbinafine use. Your doctor should check your liver function with a blood test before prescribing oral terbinafine and may repeat these tests during treatment, particularly for courses exceeding six weeks.

Warnings and precautions

When using topical terbinafine (cream, gel, or cutaneous solution), observe the following precautions:

  • Eye contact: Terbinafine cream and gel can irritate the eyes. Avoid contact with the eyes, mouth and mucous membranes. If the cream accidentally contacts the eyes, rinse thoroughly with running water and seek medical advice if discomfort persists.
  • External use only: Topical terbinafine products are for application to the skin only. Do not swallow or apply to internal body surfaces.
  • Nail infections: Topical terbinafine cream is not effective for treating fungal nail infections. If you notice discolouration, thickening, or crumbling of a nail, see your doctor for appropriate assessment and treatment.
  • Skin sensitivity: Some formulations contain excipients such as benzyl alcohol, cetyl alcohol, or stearyl alcohol that may cause local skin reactions (contact dermatitis) in sensitive individuals.

When using oral terbinafine tablets, additional precautions apply:

  • Liver function: Your doctor should assess your liver function before starting treatment and may monitor it periodically. Stop treatment immediately and seek medical advice if you develop nausea, loss of appetite, fatigue, vomiting, right upper abdominal pain, jaundice (yellowing of the skin or eyes), dark urine, or pale stools.
  • Kidney impairment: Dose adjustment may be necessary in patients with significantly reduced kidney function. Discuss your kidney health with your doctor.
  • Blood disorders: Rare cases of serious changes in blood cell counts have been reported with oral terbinafine. Contact your doctor if you develop signs of infection, unexplained bruising, or bleeding.
  • Skin reactions: Serious skin reactions such as Stevens-Johnson syndrome and toxic epidermal necrolysis have been reported rarely. Stop treatment and seek immediate medical attention if a progressive skin rash develops.
  • Taste disturbance: Loss or alteration of taste has been reported with oral terbinafine. This usually recovers within weeks to months after stopping the drug, but persistent cases have been reported.
  • Lupus erythematosus: New onset or worsening of cutaneous and systemic lupus erythematosus has been reported. If signs or symptoms suggestive of lupus develop, discontinue treatment and consult your doctor.

Pregnancy and breastfeeding

Pregnancy: Terbinafine should not be used during pregnancy unless your doctor considers it clearly necessary. Animal reproduction studies have not demonstrated any harmful effects at therapeutic doses, but clinical data on the use of terbinafine in pregnant women is limited. Since fungal skin infections are not life-threatening, treatment can generally be postponed until after delivery. If you are pregnant, think you might be pregnant, or are planning to become pregnant, seek medical advice before using any terbinafine product.

Breastfeeding: Terbinafine is excreted into breast milk. Women who are breastfeeding should not use terbinafine unless advised to do so by their doctor. If topical terbinafine is used while breastfeeding, the infant must not come into contact with treated skin areas, including the breasts. Oral terbinafine should generally be avoided during breastfeeding.

Driving and operating machinery

Terbinafine is not known to affect the ability to drive or operate machinery. However, if oral terbinafine causes dizziness or visual disturbance (which occurs rarely), you should avoid driving or using machines until these effects subside.

Excipients to be aware of (topical formulations)

Benzyl alcohol: Some terbinafine creams contain benzyl alcohol (10 mg per gram), which may cause allergic reactions and mild local irritation.

Cetyl alcohol and stearyl alcohol: These excipients can cause local skin reactions such as contact eczema in sensitive individuals. Check the patient information leaflet of your specific product for a full list of ingredients.

How Does Terbinafine Interact with Other Drugs?

Quick answer: Topical terbinafine has negligible drug interactions because minimal amounts are absorbed into the bloodstream. Oral terbinafine can interact with several medications because it inhibits the liver enzyme CYP2D6 and is metabolized by other CYP enzymes. Important interactions include increased levels of drugs metabolized by CYP2D6, and altered terbinafine levels when combined with CYP enzyme inducers or inhibitors.

Drug interactions are primarily a concern with oral terbinafine tablets. Topical terbinafine (cream, gel, solution) is absorbed into the bloodstream in such small amounts that clinically significant drug interactions are essentially absent. Nevertheless, always inform your doctor or pharmacist about all medications you are taking, including over-the-counter medicines and herbal supplements.

Oral terbinafine is metabolized by several hepatic cytochrome P450 enzymes and is a potent inhibitor of CYP2D6. This can lead to increased plasma concentrations of drugs that are substrates of CYP2D6, potentially increasing their effects or toxicity. Conversely, drugs that induce or inhibit the CYP enzymes responsible for terbinafine metabolism can alter terbinafine blood levels.

Major interactions

Major Drug Interactions with Oral Terbinafine
Drug Effect Clinical Significance
Codeine, tramadol Terbinafine inhibits CYP2D6, blocking conversion of codeine/tramadol to active metabolites Reduced analgesic efficacy; may need alternative pain relief
Tamoxifen Inhibition of CYP2D6 reduces conversion of tamoxifen to its active metabolite endoxifen Potentially reduced anticancer efficacy; combination should be avoided
Tricyclic antidepressants (e.g. amitriptyline, nortriptyline) Increased plasma levels of tricyclics via CYP2D6 inhibition Risk of toxicity (cardiac arrhythmias, CNS effects); dose adjustment may be needed
SSRIs (e.g. paroxetine, fluoxetine) Some SSRIs are CYP2D6 substrates; mutual interaction possible Monitor for increased SSRI side effects; dose adjustment may be needed
Rifampicin Powerful CYP enzyme inducer; increases terbinafine clearance by approximately 100% May render terbinafine ineffective; avoid combination or increase terbinafine dose

Minor interactions

Minor Drug Interactions with Oral Terbinafine
Drug Effect Clinical Significance
Cimetidine Inhibits CYP enzymes, reducing terbinafine clearance by approximately 33% Mildly increased terbinafine levels; generally well tolerated
Caffeine Terbinafine may decrease caffeine clearance by approximately 19% Slightly increased caffeine effects; usually clinically insignificant
Cyclosporine Terbinafine may increase cyclosporine clearance Monitor cyclosporine levels if combination is necessary
Warfarin Isolated case reports of altered INR Monitor INR when starting or stopping terbinafine; adjust warfarin dose if needed
Oral contraceptives No clinically significant pharmacokinetic interaction demonstrated Terbinafine does not reduce contraceptive efficacy; breakthrough bleeding rarely reported
Important note on CYP2D6 interactions

Terbinafine is a potent inhibitor of CYP2D6 and the inhibitory effect may persist for several weeks after stopping the drug because of its long tissue half-life. If you are taking any medications metabolized by CYP2D6 (including beta-blockers such as metoprolol, antipsychotics, or antiarrhythmics such as flecainide), your doctor should monitor you closely and may need to adjust doses. Always provide a complete list of your medications to your doctor or pharmacist.

What Is the Correct Dosage of Terbinafine?

Quick answer: For topical terbinafine cream: apply a thin layer once daily for 1 week (athlete’s foot between toes) or 1–2 weeks (jock itch, ringworm). For oral terbinafine tablets: the standard adult dose is 250 mg once daily, taken for 6 weeks (fingernails) or 12 weeks (toenails) for nail infections, or 2–6 weeks for skin infections. Children’s doses are weight-based.

Always use terbinafine exactly as described in the patient information leaflet or as directed by your doctor or pharmacist. If you are unsure, ask your doctor or pharmacist. The dosage and duration of treatment vary depending on the formulation (topical or oral), the type of infection, and the site affected.

Adults — topical use (cream, gel, cutaneous solution)

Topical Dosage Guide for Adults and Children 12 Years and Over

Condition Application Duration
Athlete’s foot (between toes) Once daily 1 week
Athlete’s foot (sole/side of foot) Once daily 2 weeks
Jock itch (tinea cruris) Once daily 1–2 weeks
Ringworm (tinea corporis) Once daily 1–2 weeks
Cutaneous candidiasis Once or twice daily 1–2 weeks

How to apply: Cleanse and thoroughly dry the affected area before application. Apply a thin layer of cream or gel to the affected skin and the surrounding area, and rub in gently. Wash your hands after application to avoid accidentally getting the product into your eyes. Symptoms typically begin to improve within a few days, but it is essential to complete the full course of treatment to prevent recurrence. If symptoms have not started to improve within two weeks, consult your doctor as your condition may not be caused by a fungal infection.

Topical terbinafine is not recommended for children under 12 years without a doctor’s prescription.

Adults — oral use (tablets)

Oral Dosage Guide for Adults

Condition Daily Dose Duration
Fungal nail infection – fingernails 250 mg once daily 6 weeks
Fungal nail infection – toenails 250 mg once daily 12 weeks (up to 16 weeks)
Tinea corporis (ringworm) 250 mg once daily 2–4 weeks
Tinea cruris (jock itch) 250 mg once daily 2–4 weeks
Tinea pedis (athlete’s foot) 250 mg once daily 2–6 weeks

Oral terbinafine tablets should be taken with a glass of water, with or without food. Taking the tablet at the same time each day helps ensure consistent blood levels. The full benefit of treatment for nail infections may not be apparent until several months after completing the course, because a healthy nail must grow out completely to replace the infected nail.

Children

Topical use: Terbinafine cream is not generally recommended for children under 12 years without a doctor’s prescription. For children aged 12 and over, the dosage is the same as for adults.

Oral use: Oral terbinafine is used in children for fungal nail infections and resistant skin infections. The dose is determined by body weight:

  • Under 20 kg: 62.5 mg once daily
  • 20–40 kg: 125 mg once daily
  • Over 40 kg: 250 mg once daily (adult dose)

Treatment duration for children follows the same guidelines as for adults depending on the type of infection. Your doctor will determine the appropriate dose and duration for your child.

Elderly

There is no evidence to suggest that elderly patients require a different dosage from younger adults. However, as the risk of pre-existing liver or kidney impairment increases with age, your doctor may wish to check your liver and kidney function before starting oral terbinafine. If kidney function is significantly reduced, your doctor may prescribe a lower dose.

Missed dose

Topical: If you forget to apply terbinafine cream, apply it as soon as you remember and then continue with your regular schedule. Do not apply a double amount to make up for the missed application.

Oral: If you miss a dose of terbinafine tablets, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule. Do not take a double dose to make up for a forgotten dose.

Overdose

Topical: Topical overdose is unlikely due to the limited skin absorption. If topical terbinafine is accidentally swallowed (for example, by a child), contact your doctor, a hospital emergency department, or a poison control centre for advice.

Oral: Overdose with oral terbinafine tablets may cause symptoms such as headache, nausea, dizziness, and abdominal pain. If a large number of tablets have been taken, seek emergency medical attention immediately. Treatment is supportive, and activated charcoal may be given if the patient presents within a few hours of ingestion.

Important: Never exceed the recommended dose

Using more terbinafine than directed does not improve results and may increase the risk of side effects. If you are unsure about your dosage or if your symptoms are not improving, consult your doctor or pharmacist rather than increasing the dose on your own.

What Are the Side Effects of Terbinafine?

Quick answer: Common side effects of topical terbinafine include mild skin peeling and itching at the application site. Common side effects of oral terbinafine include headache, gastrointestinal symptoms (nausea, diarrhea, stomach pain), skin rash, muscle and joint pain, and taste disturbance. Serious but rare side effects of oral terbinafine include severe liver injury, severe skin reactions, and blood disorders.

Like all medicines, terbinafine can cause side effects, although not everybody gets them. The type and frequency of side effects differ between topical formulations (cream, gel, solution) and oral tablets. Topical terbinafine generally causes only mild, localised reactions, whereas oral terbinafine can cause systemic side effects because the drug circulates throughout the body.

Side effects of topical terbinafine (cream, gel, solution)

Common

Affects up to 1 in 10 users

  • Skin peeling (exfoliation)
  • Itching (pruritus) at the application site

Uncommon

Affects up to 1 in 100 users

  • Skin lesion or skin damage
  • Scab or crust formation
  • Skin discolouration (pigmentation changes)
  • Redness (erythema)
  • Pain or burning sensation at application site
  • Skin irritation

Rare

Affects up to 1 in 1,000 users

  • Dry skin
  • Contact dermatitis (contact eczema)
  • Eczema

Frequency Not Known

Cannot be estimated from available data

  • Hypersensitivity reactions
  • Generalised rash (away from the application site)
  • Eye irritation (if accidentally contacts the eyes)

These side effects from topical terbinafine are usually mild and temporary. However, inform your doctor if you experience rash, blisters, or hives, as these may indicate an allergic reaction. In rare instances, the underlying fungal infection may temporarily worsen at the start of treatment.

Side effects of oral terbinafine (tablets)

Oral terbinafine has a broader side-effect profile because the drug is absorbed systemically. While most side effects are mild to moderate and resolve after stopping treatment, some can be serious. The following side effects have been reported:

Common

Affects up to 1 in 10 users

  • Headache
  • Nausea, diarrhoea, stomach pain, indigestion
  • Loss of appetite
  • Skin rash (urticaria)
  • Muscle pain (myalgia) and joint pain (arthralgia)

Uncommon

Affects up to 1 in 100 users

  • Taste disturbance (dysgeusia) or loss of taste (ageusia)
  • Decreased food intake
  • Feeling unwell (malaise)

Rare

Affects up to 1 in 1,000 users

  • Liver injury (hepatotoxicity), including jaundice
  • Severe skin reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis)
  • Blood disorders (neutropenia, thrombocytopenia, agranulocytosis, pancytopenia)
  • Photosensitivity (increased sensitivity to sunlight)
  • Dizziness, paraesthesia (tingling or numbness)
  • Hair loss (alopecia) — usually reversible
  • Lupus-like syndrome (cutaneous or systemic lupus erythematosus)
  • Depression, anxiety
  • Visual disturbance
  • Hearing impairment, tinnitus
  • Serum sickness-like reaction
When to seek immediate medical attention

Stop taking oral terbinafine and seek urgent medical care if you experience any of the following:

  • Yellowing of the skin or whites of the eyes (jaundice)
  • Unusually dark urine or pale stools
  • Persistent nausea, vomiting, fatigue, or loss of appetite
  • Widespread or blistering skin rash
  • Unexplained bruising, bleeding, sore throat, or fever
  • Severe dizziness or difficulty breathing

Taste disturbance deserves special mention as it is one of the more notable side effects of oral terbinafine. It may range from a metallic taste to partial or complete loss of taste. While it usually resolves within weeks to months after stopping the medication, persistent cases lasting several months or longer have been reported in post-marketing surveillance. If taste disturbance develops, your doctor may recommend stopping treatment.

Reporting side effects

If you experience any side effects, talk to your doctor, pharmacist, or nurse. This includes any possible side effects not listed above. You can also report side effects directly to your national medicines regulatory authority (for example, the FDA MedWatch programme in the USA, the Yellow Card Scheme in the UK, or the EMA in the EU). By reporting side effects, you help provide more information about the safety of this medicine.

How Should You Store Terbinafine?

Quick answer: Store terbinafine at room temperature, below 25°C (77°F), protected from light and moisture. Keep out of the sight and reach of children. Do not use after the expiry date printed on the packaging. Do not dispose of medicines in wastewater or household waste — return unused medicines to your pharmacy for proper disposal.

Proper storage of your terbinafine product ensures that it remains effective and safe throughout its shelf life. The following general guidelines apply to most terbinafine formulations, but always check the specific storage instructions on your product’s packaging or patient information leaflet.

  • Temperature: Store at room temperature, typically below 25°C (77°F). Do not freeze. Do not store in the bathroom or near sources of heat and moisture.
  • Light: Keep in the original packaging to protect from light.
  • Children: Keep all medicines out of the sight and reach of children. Consider using child-resistant caps and storing medicines in a locked cabinet.
  • Expiry date: Do not use terbinafine after the expiry date stated on the packaging. The expiry date refers to the last day of that month.
  • Cream/gel after opening: Once opened, use within the period recommended on the packaging. Close the tube tightly after each use.

Disposal: Do not throw medicines into the toilet or pour into drains. Do not dispose of them with household waste. Return unused or expired medicines to your pharmacist for proper disposal. These measures help to protect the environment.

What Does Terbinafine Contain?

Quick answer: The active ingredient is terbinafine hydrochloride. The inactive ingredients (excipients) vary depending on the formulation. Cream formulations typically contain benzyl alcohol, cetyl alcohol, stearyl alcohol, sorbitan monostearate, cetyl palmitate, polysorbate 60, isopropyl myristate, sodium hydroxide, and purified water. Tablet excipients include microcrystalline cellulose, sodium starch glycolate, hypromellose, colloidal silicon dioxide, and magnesium stearate.

Active ingredient

All terbinafine products contain terbinafine hydrochloride as the active substance. The amount of active ingredient depends on the formulation:

  • Cream: 10 mg terbinafine hydrochloride per gram (equivalent to 1%)
  • Gel: 1% terbinafine hydrochloride
  • Cutaneous solution: 98 mg terbinafine per ml (single-application film-forming solution)
  • Tablet: 250 mg terbinafine hydrochloride per tablet

Inactive ingredients (excipients)

Cream formulations typically contain: sodium hydroxide, benzyl alcohol (preservative), sorbitan monostearate, cetyl palmitate, cetyl alcohol, stearyl alcohol, polysorbate 60, isopropyl myristate, and purified water. The cream is white in appearance and is available in aluminium tubes of 7.5 g, 15 g, and 30 g.

Tablet formulations typically contain: microcrystalline cellulose, sodium starch glycolate (type A), hypromellose (hydroxypropyl methylcellulose), colloidal anhydrous silica, and magnesium stearate. Some formulations may also include lactose monohydrate. If you have been told by your doctor that you have an intolerance to some sugars, contact your doctor before taking the tablets.

Allergen information

Benzyl alcohol is present in some cream formulations (10 mg per gram) and may cause allergic reactions or mild local irritation in sensitive individuals.

Cetyl alcohol and stearyl alcohol are present in cream formulations and can cause local skin reactions (contact eczema) in rare cases.

Always check the full list of ingredients on your specific product’s packaging if you have known allergies or sensitivities to particular substances.

Available brands

Terbinafine is available under numerous brand names and as generic formulations worldwide. Well-known brands include Lamisil (the original brand), Lamisil Dermgel, Lamisil Singeldos (a single-application cutaneous solution), Terbisil, Terclara, Terbinafin Medical Valley, Terbinafin ABECE, and Terbinafin Teva. All products containing the same strength of terbinafine hydrochloride have equivalent therapeutic effects. Not all brands or pack sizes may be available in every country.

Frequently Asked Questions About Terbinafine

Terbinafine is an allylamine antifungal medication used to treat fungal infections of the skin and nails. Topical terbinafine (cream, gel, solution) is used for athlete’s foot, jock itch, ringworm, and cutaneous candidiasis. Oral terbinafine tablets (250 mg) are primarily prescribed for fungal nail infections (onychomycosis) and severe skin infections that do not respond to topical treatment alone.

For topical terbinafine treating athlete’s foot, symptoms usually improve within a few days, with complete healing within 1–2 weeks. For fungal nail infections treated with oral tablets, visible improvement takes 3–6 months as healthy nail grows out. Complete toenail regrowth can take 6–12 months or longer, even after the medication course is finished. Terbinafine accumulates in keratin-rich tissues and continues to work after you stop taking it.

Yes, terbinafine cream and other topical formulations (gel, cutaneous solution) are available over-the-counter without a prescription in most countries, including the UK, USA, and EU member states. However, oral terbinafine tablets require a doctor’s prescription. If symptoms do not improve within two weeks of using topical terbinafine, or if you suspect a nail infection, consult your doctor.

Terbinafine should not be used during pregnancy unless your doctor considers it absolutely necessary. There is limited clinical data on its use in pregnant women. Since fungal skin infections are not life-threatening, treatment can usually be delayed until after delivery. Terbinafine is also excreted in breast milk, so breastfeeding women should avoid it, and infants should not come into contact with treated skin areas.

For topical terbinafine, common side effects include skin peeling and itching at the application site. For oral terbinafine, common side effects include headache, nausea, diarrhoea, stomach pain, loss of appetite, skin rash, and muscle or joint pain. Rare but serious side effects of oral terbinafine include liver injury, severe skin reactions, blood disorders, and taste disturbance. Seek medical help if you develop jaundice, severe rash, or unexplained fatigue.

Yes, oral terbinafine tablets can affect liver function. Liver enzyme elevations occur in a small percentage of users, and serious liver injury including liver failure has been reported rarely. Your doctor should check liver function before starting treatment and may monitor it during the course. Stop taking oral terbinafine immediately and contact your doctor if you develop symptoms such as persistent nausea, loss of appetite, fatigue, jaundice, dark urine, or pale stools. Topical terbinafine does not significantly affect the liver.

References and Sources

All medical information in this article is based on peer-reviewed scientific literature, international clinical guidelines, and official regulatory documents. Our editorial team follows the GRADE evidence framework and adheres to international standards for evidence-based medical communication.

  1. World Health Organization (WHO). Model List of Essential Medicines – 23rd List, 2023. Geneva: WHO; 2023. Terbinafine listed under antifungal medicines.
  2. European Medicines Agency (EMA). Terbinafine – Summary of Product Characteristics (SmPC). EMA; 2024. Available from EMA product database.
  3. U.S. Food and Drug Administration (FDA). Lamisil (terbinafine hydrochloride) – Prescribing Information. Novartis Pharmaceuticals; 2023. Reference ID: FDA approved label.
  4. British National Formulary (BNF). Terbinafine Monograph. NICE Evidence Services; 2024. Available at bnf.nice.org.uk.
  5. Kreijkamp-Kaspers S, Hawke K, Guo L, et al. Oral antifungal medication for toenail onychomycosis. Cochrane Database of Systematic Reviews. 2017;(7):CD010031. doi:10.1002/14651858.CD010031.pub2
  6. Gupta AK, Mays RR, Versteeg SG, et al. Tinea capitis in children: a systematic review of management. Journal of the European Academy of Dermatology and Venereology. 2018;32(12):2264–2274. doi:10.1111/jdv.15088
  7. Ameen M, Lear JT, Madan V, et al. British Association of Dermatologists’ guidelines for the management of onychomycosis 2014. British Journal of Dermatology. 2014;171(5):937–958. doi:10.1111/bjd.13358
  8. Ryder NS. Terbinafine: mode of action and properties of the squalene epoxidase inhibition. British Journal of Dermatology. 1992;126(Suppl 39):2–7. doi:10.1111/j.1365-2133.1992.tb00001.x

Editorial Team

This article has been written and reviewed by the iMedic Medical Editorial Team, composed of licensed physicians, clinical pharmacologists, and dermatology specialists with documented academic backgrounds and clinical experience.

Medical Writing

Written by licensed physicians with specialization in clinical pharmacology and dermatology. All content is based on current international guidelines (WHO, EMA, FDA, BNF, BAD) and peer-reviewed research.

Medical Review

Independently reviewed by the iMedic Medical Review Board to ensure accuracy, completeness, and adherence to international medical standards. Evidence level: 1A (systematic reviews and randomized controlled trials).

Conflict of interest: No commercial funding. No pharmaceutical company sponsorship or advertising. Independent medical editorial content.

Editorial standards: Read our editorial standards and fact-checking policy