Terbinafine

Name: Terbinafine

Other uses for this medicine

Terbinafine is also sometimes used to treat ringworm (fungal infections of the skin that cause a red scaly rash on different parts of the body) and jock itch (fungal infection of the skin in the groin or buttocks). Talk to your doctor about the risks of using this medication for your condition.

What is the most important information i should know about terbinafine (lamisil)?

Before using terbinafine, tell your doctor if you have liver or kidney disease, or an autoimmune disorder such as lupus or psoriasis.

Take this medication for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Skipping doses may also increase your risk of further infection that is resistant to antibiotics. Terbinafine will not treat a viral infection such as the common cold or flu.

Some people taking terbinafine have developed severe liver damage leading to liver transplant or death. It is not clear whether terbinafine actually caused the liver damage in these patients. In most cases, the patient had a serious medical condition before taking terbinafine.

Call your doctor at once if you have symptoms of liver damage, such as nausea, upper stomach pain, itching, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes). These events can occur whether or not you have ever had liver problems before.

To be sure this medicine is not causing harmful effects, your blood may need to be tested often. Your liver function may also need to be tested. Visit your doctor regularly.

It may take several months for your nails to return to their normal appearance after your treatment with terbinafine.

Terbinafine Overview

Terbinafine is both an over-the-counter and a prescription medicine used to treat fungal infections. The over-the-counter forms (cream, gel, sprays) are used to treat itching, burning, cracking and scaling caused by athlete's foot, jock itch, and ringworm. The prescription forms (tablets and oral granules) are used to treat fingernail and toenail fungal infections and a fungal infection of the scalp that usually occurs in children. This medication page refers to the prescription form of terbinafine.

Terbinafine belongs to a group of drugs called antifungals. It works by stopping the growth of fungi.

Terbinafine tablets are taken once daily for up to 12 weeks, with or without food. Terbinafine oral granules are sprinkled on food and taken by mouth once daily.

Common side effects of terbinafine include headache.

Terbinafine Brand Names

Terbinafine may be found in some form under the following brand names:

  • Desenex Max

  • Lamisil

  • Terbinex

Terbinafine Precautions

Terbinafine may cause serious side effects, including:

  • liver problems that can lead to the need for liver transplant, or death. Your doctor should do a blood test to check you for liver problems before you take terbinafine. Tell your doctor right away if you get any of these symptoms of a liver problem:
    • nausea        
    • upper right stomach (abdominal) pain
    • poor appetite  
    • yellowing of your skin or eyes (jaundice)
    • tiredness
    • dark (tea-colored) urine 
    • vomiting    
    • pale or light colored stools
  • change in taste or loss of taste may happen with terbinafine. This usually improves within several weeks after stopping terbinafine, but may last for a long time or may become permanent. Tell your doctor if you have:
    • change in taste or loss of taste
    • poor appetite 
    • unwanted weight loss
  • change in smell or loss of smell may happen with terbinafine. This may improve after stopping terbinafine, but may last for a long time or may become permanent. 
  • depressive symptoms. Tell your doctor right away if you have any of these signs or symptoms:
    • feel sad or worthless 
    • change in sleep pattern
    • loss of energy or interest in daily activities 
    • restlessness
    • mood changes 
  • serious skin or allergic reactions. Tell your doctor right away or get emergency help if you get any of these symptoms:
    • skin rash
    • hives
    • sores in your mouth, or your skin blisters and peels
    • swelling of your face, eyes, lips, tongue or throat, trouble swallowing or breathing
  • new or worsening lupus (autoimmune disease). Stop taking terbinafine and tell your doctor if you experience any of the following:
    • progressive skin rash that is scaly, red, shows scarring, or loss of pigment
    • unusual sensitivity to the sun that can lead to a rash

Do not take terbinafine if you are allergic to terbinafine hydrochloride when taken by mouth.

Terbinafine and Lactation

Tell your doctor if you are breastfeeding or plan to breastfeed. Some terbinafine passes into your milk and may harm your baby. Talk to your doctor about the best way to feed your baby if you take terbinafine.

Terbinafine Usage

Take terbinafine exactly as your doctor tells you to take it. 

Terbinafine Tablets

  • Terbinafine comes as a tablet that you take by mouth.
  • Terbinafine is usually taken:
    • 1 time each day for 6 weeks to treat fungal infections of your fingernail, or 
    • 1 time each day for 12 weeks to treat fungal infections of your toenail 
  • You can take terbinafine with or without food.
  • If you forget to take terbinafine, take your tablets as soon as you remember, unless it is less than 4 hours before your next dose is due.  In this case, wait and take your next dose at the usual time. 

Terbinafine Oral Granules

Terbinafine comes as oral granules that are sprinkled on food and taken by mouth.

One to two packets should be taken each day with a soft non-acidic food (see instructions below). If two packets are required with each dose, you may either sprinkle the content of both packets on one spoonful of non-acidic food, or sprinkle the contents of both packets on two spoonfuls of non-acidic food as directed below.

  1. Hold packet with cut line on top.
  2. Shake packet gently to settle contents.
  3. Tear packet open along cut line, or use scissors to cut across line.
  4. Carefully pour entire contents of packet onto a spoonful of a soft food, such as pudding or other soft, non-acidic food such as mashed potatoes (do not use applesauce or a fruit-based food). 
  5. Make sure that no granules remain in the packet.
  6. Swallow combination of food and granules without chewing.

What should I discuss with my healthcare provider before taking terbinafine?

You should not use terbinafine if you are allergic to it, or if you have:

  • liver disease.

To make sure terbinafine is safe for you, tell your doctor if you have ever had:

  • liver problems;

  • weak immune system (caused by disease or by using certain medicine); or

  • lupus.

It is not known whether this medicine will harm an unborn baby. You should wait until after your pregnancy to start treating your nail or scalp infection with terbinafine. Tell your doctor if you are pregnant or plan to become pregnant during treatment.

Terbinafine can pass into breast milk and may harm a nursing baby. You should not breast-feed while using this medicine.

Overdosage


Clinical experience regarding overdose with oral Terbinafine is limited. Doses up to 5 grams (20 times the therapeutic daily dose) have been taken without inducing serious adverse reactions. The symptoms of overdose included nausea, vomiting, abdominal pain, dizziness, rash, frequent urination, and headache.

Terbinafine - Clinical Pharmacology

Mechanism of Action


Terbinafine is an allylamine antifungal [see Clinical Pharmacology (12.4)].

Pharmacodynamics

The pharmacodynamics of Terbinafine tablets is unknown.

Pharmacokinetics

Following oral administration, Terbinafine is well absorbed (greater than 70%) and the bioavailability of Terbinafine tablets as a result of first-pass metabolism is approximately 40%. Peak plasma concentrations of 1 mcg/mL appear within 2 hours after a single 250 mg dose; the AUC is approximately 4.56 mcg•h/mL. An increase in the AUC of Terbinafine of less than 20% is observed when Terbinafine tablets are administered with food.


In plasma, Terbinafine is greater than 99% bound to plasma proteins and there are no specific binding sites. At steady-state, in comparison to a single dose, the peak concentration of Terbinafine is 25% higher and plasma AUC increases by a factor of 2.5; the increase in plasma AUC is consistent with an effective half-life of ~36 hours. Terbinafine is distributed to the sebum and skin. A terminal half-life of 200 to 400 hours may represent the slow elimination of Terbinafine from tissues such as skin and adipose. Prior to excretion, Terbinafine is extensively metabolized by at least 7 CYP isoenzymes with major contributions from CYP2C9, CYP1A2, CYP3A4, CYP2C8, and CYP2C19. No metabolites have been identified that have antifungal activity similar to Terbinafine. Approximately 70% of the administered dose is eliminated in the urine.

In patients with renal impairment (creatinine clearance less than or equal to 50 mL/min) or hepatic cirrhosis, the clearance of Terbinafine is decreased by approximately 50% compared to normal volunteers. No effect of gender on the blood levels of Terbinafine was detected in clinical trials. No clinically relevant age-dependent changes in steady-state plasma concentrations of Terbinafine have been reported.

Microbiology


Terbinafine, an allylamine antifungal, inhibits biosynthesis of ergosterol, an essential component of fungal cell membrane, via inhibition of squalene epoxidase enzyme. This results in fungal cell death primarily due to the increased membrane permeability mediated by the accumulation of high concentrations of squalene but not due to ergosterol deficiency. Depending on the concentration of the drug and the fungal species test in vitro, Terbinafine hydrochloride may be fungicidal. However, the clinical significance of in vitro data is unknown.

Terbinafine has been shown to be active against most strains of the following microorganisms both in vitro and in clinical infections:

Trichophyton mentagrophytes
Trichophyton rubrum

The following in vitro data are available, but their clinical significance is unknown. In vitro, Terbinafine exhibits satisfactory MIC’s against most strains of the following microorganisms; however, the safety and efficacy of Terbinafine in treating clinical infections due to these microorganisms have not been established in adequate and well-controlled clinical trials:

Candida albicans
Epidermophyton floccosum
Scopulariopsis brevicaulis

Usual Adult Dose for Tinea Pedis

Some experts recommend:
-Tablets: 250 mg orally once a day for 2 to 6 weeks

Dialysis

Data not available

Other Comments

Administration advice:
-Oral granules: Administer with food. Sprinkle the contents of each packet on a spoonful of pudding or other soft, nonacidic food (e.g., mashed potatoes) and swallow the entire spoonful without chewing; do not use applesauce or fruit-based foods. If 2 packets needed with each dose, may sprinkle both packet contents on 1 or 2 spoonfuls of nonacidic food
-Consult the manufacturer product information regarding missed doses.

Storage requirements:
-Oral granules: Store at 25C (77F); excursions permitted to 15C to 30C (59F to 86F).
-Tablets: Store below 25C (77F) in tight container; protect from light.

General:
-Clinical resolution may not be observed until several weeks after mycological cure.
-Oral granules were not studied in geriatric patients.

Monitoring:
-Hematologic: Complete blood counts in patients with known/suspected immunodeficiency if therapy continues beyond 6 weeks or in patients with clinical signs/symptoms suggestive of secondary infection
-Hepatic: For evidence of chronic or active liver disease; liver function tests (before therapy, then periodically)
-Psychiatric: For depressive symptoms

Patient advice:
-Read the US FDA-approved Medication Guide; if using the oral granules, also read the Instructions for Use.
-Minimize exposure to natural and artificial sunlight (tanning beds or ultraviolet A/B treatment) during therapy.
-Contact physician or seek medical care immediately if any of the following symptoms develop: hives, mouth sores, blistering/peeling of skin, swelling (of face, lips, tongue, throat), problems swallowing/breathing.
-Contact physician at once if symptoms of liver injury (persistent nausea, anorexia, fatigue, vomiting, right upper abdominal pain, jaundice, dark urine, pale stools) develop.
-Consult physician if any signs of taste/smell disturbance, depressive symptoms, fever, skin eruption, lymph node enlargement, erythema, scaling, loss of pigment, or unusual photosensitivity (that can result in rash) occur.

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