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How Long Does Terbinafine Take To Work?

Fungal infections can be very damaging and cause much suffering. Especially interdigital infections, itchy-scaly skin, fluid-filled blisters, etc. It is natural to get worried if the antifungal doesn’t show any effects soon. Moreover, there can be a spread of the primary infection to other body parts.

So, how long does terbinafine take to work and when do we start seeing significant clinical effects?

Terbinafine is an antifungal drug used mainly in skin infections. It usually takes around one month to start healing symptoms. But jock itch and athlete’s foot are supposed to heal faster. There are multiple side effects related to different body systems. Proper history and diagnosis are a must before its prescription.

To know more elaborately, give the following segments a read.

Table of Content

How Long Does Terbinafine Take To Work?

This is significant as many patients face troubles and get confused with the treatment period.

Beginning of Healing

The treatment period for most patients is between 6 weeks to 3 months. 

The symptoms start to heal after the end of one month in most patients. There are exceptions too. 

You should not think that your medicine is not working in the first 1 or 2 months. However, if complications arise like the infection spreading to other body parts, immediately call your doctor.


The patients requiring long-term therapy can be identified by checking their nail conditions. Their nail outgrowths are comparatively poor in the first few weeks

Complete Healing

Your condition will continue to heal even after finishing treatment.

It is normal to take several weeks for the elimination of infections, after completing treatment.


Jock itch and athlete’s foot are supposed to heal faster than others.

Inform your doctor if your jock itch doesn’t start improving after 2 weeks of treatment. And also if your athlete’s foot doesn’t improve after 4 weeks of treatment.

Steps To Be Followed For Efficacy During Treatment

These include the following:

  • If you miss an oral dose, take it immediately after you have remembered. If the next regular dose is less than 4 hours away, then skip the missed dose.
  • Keep the medicine away from heat, direct light, moisture, and freezing. Keep it away from children.
  • Check for outdated medicines & get rid of them. Ask advice from your doctor about ways of disposing of different medicines.
  • Avoid applesauce or fruit-based foods in case you want to mix your oral granules with food. Avoid caffeine products as much as possible while you’re under terbinafine medication.
  • To remove the infection completely, you have to complete the full dosage schedule. Don’t stop it if your symptoms fade away soon. Otherwise, there can be a relapse of the disease.
  • Use the cream on the skin only. Wash your unaffected hands properly after touching the cream.
Don’t wrap or cover the affected area without asking your doctor. Also, the cream is not supposed to be used on the scalp or nails normally.

If the cream accidentally comes in contact with the eyes, nose, mouth, or vagina, wash thoroughly with water.

  • Stop using it and inform your doctor immediately if the symptoms worsen with medication.
  • Don’t use it more than directed. Otherwise, side effects can appear.

So, now you know how long you need to wait for cure after starting the Terbinafine course. But don¨t you think it is important to have some basic idea about the medicine you are using? For me, it¨s a yes!

Hence, the next segment is designed to give you a brief on the basics regarding Terbinafine. 

Terbinafine- A General Overview

Terbinafine can be briefly described as follows:

Drug Class

Terbinafine is sold under the brand name Lamisil. It is a systemic drug and belongs to the class of antifungals.


Dosage Forms & Schedule With Routes Of Administration

These include,

Oral Terbinafine Tablets

You can take terbinafine tablets both on an empty or a full stomach. Now,

  • For adults:

In case of fingernail and toenail infections, take 250 mg once daily for 6 weeks. For toenail infections, take 250 mg once daily for 12 weeks. For ringworm of the body, groin, etc. take 250 mg once daily for 2 to 4 weeks. And for ringworm of the foot, take 250 mg once daily for 2 to 6 weeks.

  • For children:

The doctor usually determines the dose which is different for different children as per their body weight.

Oral Terbinafine Granules

These should be taken with food for efficacy. You can sprinkle the granules in a spoonful of soft non-acidic food. It must be swallowed immediately and not chewed. Now,

  • For adults:

The dose is usually 250 mg once daily for 6 weeks. It can change based on body weight.

  • For children:

The dose is determined by the doctor for different patients according to their physique. Usually, it is:

  • 250 mg once daily for 6 weeks in the case of children of 4 years or older and >35 kg.
  • 187.5 mg once daily for 6 weeks in the case of children of 4 years or older and (25 to 35) kg.
  • 125 mg once daily for 6 weeks in the case of children of 4 years or older and <25 kg.
  • The usual dose for children <4 years is not fixed.

Topical Terbinafine Cream

It is applied as a thin layer on & around the affected area once or twice daily. The doctor will give related advice if necessary.


The pharmacodynamics of Terbinafine is its actions, especially on the body.

How Terbinafine Works

It works by preventing the growth of fungus. Fungi have ergosterol as the main component of their cell membrane. An enzyme (squalene monooxygenase) is needed to produce this sterol in fungi. Terbinafine inhibits this enzyme. So, ultimately the fungal cell membranes get disrupted and the fungi die.

Drug Interactions

The well-defined interactions of terbinafine are as follows:

  • Terbinafine inhibits a particular enzyme (CYP450 2D6) of the body. This enzyme metabolizes drugs of particular classes. For example, Beta-blockers (anti-hypertensive), tricyclic antidepressants (mood uplifter), monoamine oxidase inhibitors (variable functions), etc.

So, when that enzyme is inhibited by terbinafine, it can no longer metabolize these drugs when needed. As a result, the concentrations of these drugs rise in the body. These can cause drug toxicity and other adverse effects. 

So, when terbinafine is co-administered with any of these drugs, then careful monitoring is needed. A reduction in the doses of those other drugs might be necessary.

  • More studies have found that terbinafine makes caffeine stay longer in the body. And it makes the drug cyclosporine stay shorter in the body than normal duration.
  • Co-administration of some drugs (like fluconazole, ketoconazole, etc.) with terbinafine tends to increase its systemic exposure. So, the effects may increase or alter accordingly.
  • Terbinafine stays longer in the body when co-administered with the drug cimetidine. But it stays very short in the body when co-administered with the drug rifampin.
  • The influence of the following common drugs on terbinafine is not known yet. So, use them with proper monitoring.
    • Oral Contraceptive Pills (OCP)
    • Hypoglycemic (sugar reducing agents)
    • Hormone replacement therapies
    • Thiazide diuretics (used in moderate hypertension)
    • Calcium channel blockers (mainly anti-arrhythmic)
  • Terbinafine effects can slightly increase with food but it is not harmful.


The pharmacokinetics of terbinafine means the actions of the body upon this drug.

After oral administration, terbinafine is well absorbed. But its bioavailability is reduced due to first-pass metabolism. Its concentration in plasma peaks at 1 microgram/mL.

 It occurs within 2 hours of taking a single 250 mg oral tablet. It is mainly metabolized by liver enzymes. About 70% of the given dose is eliminated through urine.

Indications of Using Terbinafine

It is commonly used in,

  • Different types of fungal skin infections. Like ringworm, athlete’s foot, jock itch, etc.
  • Pityriasis causes pigmentation of the neck, legs, chest, and arms. Oral tablets are not applicable for it.
  • Lamisil (terbinafine hydrochloride) tablets are taken for the treatment of fungal infection affecting nails.


It can not be used in,

  • Patients whose creatinine clearance is less than 50 due to any other disorders. It can be checked in the laboratory.
  • Patients with hepatic diseases.
  • Immunodeficient persons
  • Patients suffering from systemic lupus erythematosus (SLE).

Adverse Effects

The adverse effects of terbinafine can be associated with multiple organ systems. Like,

  • Nausea, rash, urticaria, alopecia (hair loss, malaise (general discomfort), fever, fatigue, influenza-like illness, etc.
  • Blood disorders like anemia, low WBC count, low platelet count, etc.
  • Liver disorders include hepatitis, cholestasis, etc. These can even lead to liver failure. It may require a liver transplant in future. 

This is first manifested as dark urine, jaundice, etc.

  • Psychiatric disorders like anxiety, depressive symptoms, etc.
  • Nervous system disorders like taste disturbances lead to decreased food intake, weight loss, etc. Cases of smell-loss are seen too.
  • Gastrointestinal disorders like pancreatitis, vomiting, etc.
  • Skin and subcutaneous tissue disorders like dermatitis, epidermal necrolysis, etc.
  • Musculoskeletal & connective tissue disorders like arthralgia (joint pain), myalgia (muscle pain), etc.


Which is more effective? Terbinafine cream or tablets?

Answer: Both terbinafine cream and tablets are effective in different situations. In many cases, patients are given terbinafine tablets after side effects appear with the cream. Pityriasis is treated with the cream and oral tablets aren’t applicable.

What foods should be avoided while taking terbinafine?

Answer: Avoid having coffee, tea, cola, energy drinks, etc. Don’t take terbinafine oral granules with fruit-based or acidic foods. 

Is terbinafine the best drug for all fungal infections?

Answer: No. Terbinafine works most effectively in case of fingernail infections. Other antifungal drugs include ketoconazole, fluconazole, miconazole, etc. Each is effective for different disorders.

End Note

Now if we ask you how long does terbinafine take to work, will you be confident and clear? So, we hope you won’t get tense if you see no results using terbinafine soon. Follow the guidelines properly and always remember to complete the dose normally. Good luck!

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