How long does it take for Terbinafine to work on toenail fungus?

In this brief article, we will discuss the approximate time taken by Terbinafine to work on toenail fungus, which is one of the most common fungal infections. We will also discuss the safe and effective use of Terbinafine for maximum symptom relief and other alternatives available if the medication fails to treat your condition. 

How long does it take for Terbinafine to work on toenail fungus?

Terbinafine can typically take anywhere from 6 to 24 weeks to work on toenail fungus (1). However, the exact treatment duration can vary from person to person. 

Some individuals may experience faster results, while others may require more extended treatment periods. The severity of the fungal infection plays a crucial role in determining the treatment duration. More severe infections may take longer to clear up completely (1).

Oral Terbinafine is often considered more effective for toenail fungus because it stays in the nails for a longer time, allowing it to target and eradicate the fungus more efficiently. This sustained presence in the nails contributes to better treatment outcomes compared to topical applications alone.

It’s essential to follow your healthcare provider’s instructions and complete the full course of treatment for the best chance of success in treating toenail fungus.

How does Terbinafine work against toenail fungus? 

Terbinafine works against toenail fungus by targeting and inhibiting an enzyme called squalene epoxidase, which is essential for the synthesis of ergosterol, a crucial component of the fungal cell membrane (2). 

By blocking this enzyme, Terbinafine disrupts the production of ergosterol, weakening the fungal cell walls and leading to their eventual death.

In simpler terms, Terbinafine interferes with the growth and structure of the toenail fungus, making it unable to survive and thrive. As a result, the fungal infection gradually clears up, and new healthy nail growth can take its place (2). 

Terbinafine is considered far more effective for toenail fungus compared to other antifungal agents like Itraconazole, Fluconazole and Griseofulvin (3).

Dosage form recommendations of Terbinafine for toenail fungus

Terbinafine for toenail fungus is commonly available in two dosage forms: oral tablets and topical cream.

Oral tablets

These are taken by mouth and are usually prescribed for more severe or widespread toenail fungus infections. The tablets are absorbed into the bloodstream, allowing Terbinafine to reach the infected nails through the blood supply. 

Oral tablets are effective as the medication stays in your nails for a longer period, helping to treat the infection more efficiently.

The recommended dosage for onychomycosis (toenail fungus) in adults is 250 mg once a day. The typical treatment duration with oral tablets is 12 weeks (4). However, in some cases, your healthcare provider may adjust the dosage or treatment duration based on individual factors.

Topical cream

The topical cream is applied directly to the affected toenails and the surrounding skin. It is typically recommended for mild to moderate toenail fungus infections or as a maintenance treatment after using oral tablets. 

While topical creams are convenient to apply, they may not penetrate as deeply into the nail bed as oral tablets.

What are the common side effects of Terbinafine when used for toenail fungus?

Terbinafine, although it is well-tolerated, can cause some side effects when used for toenail fungus or any other reason. These include (5):

  • Headache
  • Itching
  • Changes in mood (feeling sad, worthless, restless, or other mood changes)
  • Loss of energy or interest in daily activities
  • Diarrhoea
  • Indigestion
  • Sleep disturbances

Terbinafine may also cause some less common or rare side effects, including: (5)

  • Loss of appetite
  • Extreme tiredness
  • Pain in the right upper part of the stomach
  • Dark urine
  • Pale stools
  • Yellowing of the skin or eyes
  • Severe skin rash that keeps getting worse
  • Fever, sore throat, and other signs of infection
  • Swelling of the face, throat, tongue, lips, and eyes
  • Difficulty swallowing or breathing
  • Hoarseness
  • Swollen lymph glands
  • Peeling, blistering, or shedding skin

These side effects can vary from person to person, and not every individual experiences these side effects. However, one should get immediate medical attention if an allergic reaction occurs. 

What are the alternatives to Terbinafine for toenail fungus?

If you cannot use Terbinafine for toenail fungus due to reasons like allergic reactions or other contraindications, there are alternative antifungal options that your doctor may explore. These alternatives include medications like Itraconazole, Fluconazole, Griseofulvin, etc (6).

However, it is crucial to consult your healthcare provider before starting any alternative treatment, as they will consider your specific medical history and conditions to determine the most suitable option for you.


In this article, we have discussed the time taken by Terbinafine to work for toenail fungus. We have also discussed the clinical significance of Terbinafine in the treatment of toenail fungal infections and some alternative options if the medication fails to work effectively. 

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National Health Service. How and when to take or use terbinafine. [Internet]. London: National Health Service (NHS); [Cited 2023 Aug 1]. Available from:


Maxfield L, Preuss CV, Bermudez R. Terbinafine. 2023 May 29. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan–. PMID: 31424802.


Darkes MJ, Scott LJ, Goa KL. Terbinafine: a review of its use in onychomycosis in adults. Am J Clin Dermatol. 2003;4(1):39-65. doi: 10.2165/00128071-200304010-00005. PMID: 12477372.


Tausch I, Bräutigam M, Weidinger G, Jones TC. Evaluation of 6 weeks treatment of terbinafine in tinea unguium in a double-blind trial comparing 6 and 12 weeks therapy. The Lagos V Study Group. Br J Dermatol. 1997 May;136(5):737-42. PMID: 9205509.


National Library of Medicine. Terbinafine: MedlinePlus Drug Information [Internet]. Bethesda (MD): U.S. National Library of Medicine; 2022 [cited 2023 Aug 1]. Available from:


Gupta AK, Stec N. Recent advances in therapies for onychomycosis and its management. F1000Res. 2019 Jun 25;8:F1000 Faculty Rev-968. doi: 10.12688/f1000research.18646.1. PMID: 31297182; PMCID: PMC6600855.