Terbinafine (Lamisil)

Terbinafine (Lamisil)

Terbinafine is a substance used to treat various forms of fungal infection, including toenail infections, fingernail infections, athlete’s foot and more. The material works by eliminating the conditions required for the growth of fungus on the human body. More information

A doctor will review your order and write you a prescription, if appropriate. This prescription is then forwarded to a pharmacy. The pharmacy will have your medicine delivered to you within one to three working days. Read more about this process here.

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Patient Leaflet(s)

Terbinafine is a form of anti-fungal medication used to treat a range of fungal infection conditions. If you suffer from infections involving the growth of fungus on the groin, body, scalp, feet, toenails or fingernails, your doctor may give you a long-lasting dose of Terbinafine to address the condition.  

Terbinafine is also available under the branded name "Lamisil."  

What is Terbinafine? 

Terbinafine is a substance used to treat various forms of fungal infection, including toenail infections, fingernail infections, athlete’s foot and more. The material works by eliminating the conditions required for the growth of fungus on the human body. Terbinafine belongs to a wider group of medications called antifungals. 

Terbinafine works by causing holes to appear in the cell membranes in the fungi on your body. The membranes on fungi are crucial to their survival, as they prevent unwanted substances from entering the cells.  

Although Terbinafine is an effective treatment for many patients, it can take several months after you have already finished your full course of treatment before you begin to see an obvious change in your condition. It takes time for new skin and nails to grow and replace the infected areas on your body. Continue to take the medication until the prescribed amount is finished. 

Make sure that you do not continue to take the treatment for longer than your doctor has suggested. Treatment may be needed for anywhere between two weeks to six months for some complex nail infections. 

When is Terbinafine used? 

Terbinafine is used to treat a range of fungal infections in the skin, body, and nails. It is always required that you complete the prescribed course when taking Terbinafine because fungus can continue to grow and become resilient to the drugs you are taking if you fail to follow your doctor's instructions. You may feel reduced appetite or suffer from some stomach problems when taking Terbinafine.  

It can take a while for your Terbinafine to appear as though it's completely cured when you're taking Terbinafine. Your pharmacist or doctor will give you a complete information sheet that you can follow when taking this medication.  

Aside from common nail infections, Terbinafine is also sometimes recommended for the treatment of ringworm. Ringworm is a skin infection that causes red and scaly rashes on specific parts of the body. It can also be effective for jock itch: a condition that refers to the fungal infection of skin around the buttocks or groin. 

How do you use Terbinafine? 

Your doctor will provide you with instructions for how you should take your Terbinafine. Do not take more or less of the dosage prescribed to you and do not take it for longer than your doctor ordered. This medicine will come with patient instructions to guide you. If you are confused by any of the instructions given, speak to your doctor.  

Terbinafine can come in the form of granules or tablets. To help clear up your fungal infection, take your medication with food or on an empty stomach. Granules are best taken with food. You will also need to take the full treatment, even if you start to notice your symptoms improving before your course of treatment is over.  

Terbinafine works best when you can maintain a consistent amount of the active ingredient in the blood. This means that you should avoid missing dosages and try to take your dose at the same time each day. Most doctors will prescribe 250mg tablets which you can take once per day.  

If you decide to use oral granules for your Terbinafine, then you may sprinkle the contents onto your food, but you will have to swallow the substance immediately without chewing. You will also not be able to use the granules with acidic foods or fruit-based foods. You will need to avoid caffeine, chocolate, soda, and coffee when taking Terbinafine.  

What dosages are available? 

The dose of Terbinafine provided for you will differ depending on your condition and prior medical history. The most common dose for the tablet version of the medication is 250mg once a day. However, the length of time you're required to take the tablet for will depend on your condition. For fungus infections of the fingernails, 6 weeks is common. A twelve-week course of 250mg per day is recommended for fungal infections of the toenails. For ringworm of the body or jock itch, you will need to take 250mg per day for at least 2 to 4 weeks. For athlete’s foot, most courses last for between 2 to 6 weeks.  

If you're taking Terbinafine in the granule form, you will be given a dose based on your body weight. Again, usually, the dose is 250mg, with a course that lasts according to your condition. Expect to take 250mg once a day for 6 weeks if you have fungal infections of the scalp and weigh more than 35 kilograms.  

What are the side effects of Terbinafine? 

Aside from the necessary effects of Terbinafine, there's a risk that you will also experience some unwanted side effects. Usually, the side effects common with Terbinafine are very mild and will rectify themselves without any specific assistance or treatment from your doctor.  

Common side effects for those taking Terbinafine are usually reduced appetite, indigestion, stomach aches, and feeling sick. You may also experience instances of diarrhea in some cases. If these effects last for a long period of time or get worse, contact your pharmacist or doctor. 

Some people taking Terbinafine also feel as though their muscles and joints are aching, and may begin to develop a rash. If you do notice a rash, this could be a sign that you are having an allergic reaction to the drug. Other common signs of an allergic reaction include dizziness, trouble breathing, and swollen lymph nodes. Be cautious of any fever or swelling in the tongue, throat, or mouth after taking Terbinafine.  

Tell your doctor immediately and stop taking Terbinafine if you notice any more uncommon side effects. For instance, some people experience changes in their taste or sense of smell. These side effects often improve after you have stopped taking Terbinafine. In some cases, however, they can become permanent when not addressed. You will also need to tell your doctor if you experience any changes to your vision, or mental or mood changes such as depression.  

Other more dangerous side effects include signs of kidney problems, such as a change in the number of times you urinate, unusual tiredness, unexplained bruising or bleeding. In very rare conditions, Terbinafine may cause serious liver disease problems. If you notice any symptoms of liver damage, including vomiting and nausea, loss of appetite, severe abdominal and stomach pain, or yellowing skin or eyes, get emergency help. Dark yellow urine can also be a sign of liver failure.  

When shouldn't you use Terbinafine? 

Terbinafine is not appropriate for all people. Some people will not respond well to this tablet. Before starting a dose of Terbinafine, you should always speak to your doctor or pharmacist in depth about your medical history. Let them know if you have any allergies that may affect your chances of side effects with this medication.  

Before using this substance, speak to your doctor if you have any history of immune system problems, liver disease, or kidney disease. If you have a risk of lupus, or you drink a lot of alcohol, you should also avoid taking Terbinafine, unless your doctor advises you otherwise.  

In some cases, Terbinafine can make people more sensitive to the sun. To reduce your risk of dangerous skin damage, make sure that you limit your time in the sun and reduce your exposure to sunlamps and tanning booths. Always wear protective clothing and sunscreen when outdoors and tell your doctor if you develop blisters or burns. 

This medication should only be used when absolutely necessary during pregnancy. Fungal nail infection treatments can usually wait until after the baby has been born. Additionally, this medication can pass into breast milk, and may have negative effects on a nursing baby. It is not a good idea to breastfeed when using this drug.  

Does Terbinafine interact with any other medications? 

Terbinafine may interact with other medications that are part of your daily schedule. Interactions between drugs can affect how your medications work and increase the chances that you may suffer from serious side effects. Remember that you should always take a list of all the products you use to your doctor when getting a prescription for new medications. This will include any drugs you are taking, including prescribed and non-prescription medications, herbal substances and supplements. 

Do not stop, start, or change the dosage of any drug without approval from your doctor. The following drugs can have interactions with Terbinafine: 

  • Caffeine 
  • Medicines used for the treatment of coughs (dextromethorphan) 
  • Medicines used for the treatment of fungal infections like ketoconazole or fluconazole 
  • Medicines used to control the body's immune system and prevent the rejection of transplanted organs such as ciclosporin 
  • Medicines for the treatment of heart problems like amiodarone or propafenone 
  • Medicines used to thin the blood such as warfarin 
  • Anti-arrhythmic or beta-blockers for heart conditions 
  • Anti-depressants like amitriptyline, nortriptyline, fluoxetine, imipramine, paroxetine, and others 
  • Oral contraceptives 
  • Cimetidine to treat stomach ulcers or manage stomach acid 
  • Antibiotics to treat infections and fever such as rifampicin 

You may need a blood test before and after you begin taking Terbinafine so that your doctor can monitor the functioning of your liver. This is more likely to be necessary if you have a higher risk of liver issues or a family history of liver conditions.  

Some people feel dizzy when taking Terbinafine if you feel this way it's important to avoid operating heavy machinery or driving until you feel fully capable again.  

Where can you buy Terbinafine? 

If you have a prescription, then you will be able to buy Terbinafine from any registered offline or online pharmacy after filling out a medical information form. Make sure that you are purchasing your medication from a reputable source.  

Can you get Terbinafine without a prescription?  

Terbinafine is not available without a prescription. It is dangerous to take this substance without first getting the approval of your doctor.  




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Assessed by:

Dr Imran Malik, General practitioner
Registration number: GMC: 4741365

Dr Imran Malik studied undergraduate medicine at King's College University in Central London and clinical studies at the prestigious King's College Hospital. He graduated with a MBBS degree in 2000 and went on to gain postgraduate memberships with the Royal Society of Medicine and also General Practice in 2006.