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Common questions about terbinafine - Brand names: Lamisil, Lamisil Once

How does terbinafine work?

Terbinafine is an antifungal medicine. It works by killing the fungus that is causing the infection.

It makes holes in the cell membrane of the fungus and the contents leak out. This kills the fungus and treats the infection.

When will I feel better?

It depends on the type of infection you have. Some will take longer to get better.

Terbinafine solution usually starts to work within a few days. Talk to your doctor if your symptoms do not get better within 1 week.

The cream, gel or spray usually starts to work within a few days. Talk to your doctor if your symptoms do not get better within 2 weeks.

Terbinafine tablets can take several weeks to work. If you have completed the course of tablets and still have symptoms, talk to your doctor.

Some fungal nail infections take 6 months or longer to get better. Nail infections often get better more quickly in younger people. Infections on the big toe often take longer to clear up than on other toes.

Are there any long-term side effects?

Terbinafine is usually used for a short time to clear an infection. Do not use it for longer than your pharmacist or doctor has recommended.

If you use it too often or for too long, the medicine may not work so well. This is because fungal infections can become resistant to terbinafine.

For some infections, such as fungal nail infections, you may need to take terbinafine tablets for up to 3 months (sometimes longer). It's safe to take long term if your doctor tells you to.

What if it does not work?

If taking terbinafine is not working to clear an infection, your doctor may ask you to take it for longer or they may prescribe a different antifungal medicine.

If your symptoms get worse at any time, speak to your doctor.

Are there other medicines for fungal infections?

There are many different antifungal medicines. Some are available to buy from a pharmacy, and others are available on prescription.

They can come as creams, gels and sprays, pessaries (soft tablets you put into your vagina), tablets, capsules and liquid, or injections.

Your doctor or a pharmacist will be able to recommend the best treatment for you, based on your condition.

Other antifungal medicines include:

Do I need to have blood tests if I'm taking terbinafine tablets?

If you take terbinafine tablets for a long time, your doctor may ask you to come back for a blood test. This is to check that your liver is working properly.

There is a small chance (less than 1 in 1,000) that terbinafine can affect your liver.

Will it affect my contraception?

Terbinafine is not likely to affect your contraception, including the combined pill or emergency contraception.

If taking terbinafine makes you sick (vomit) or have severe diarrhoea for more than 24 hours, your contraceptive pills may not protect you from pregnancy. Look on the pill packet to find out what to do.

Find out more:

There have been some reports of breakthrough bleeding, known as spotting, when people take terbinafine tablets and the combined pill together. It's not known whether this is to do with the terbinafine. If you get any breakthrough bleeding while using oral contraception, speak to your doctor.

Can I donate blood if I'm using or taking terbinafine?

If you're using terbinafine cream, gel, spray or solution, then it's OK to donate blood.

But if you're taking terbinafine tablets, it's important to wait at least 7 days after completing the course of tablets before giving blood.

You can check if you're able to give blood on the NHS Give Blood website.

Can I drive or ride a bike?

You can drive or cycle while taking terbinafine if you feel OK.

But if taking terbinafine makes you feel dizzy, tired or very unwell, do not drive or ride a bike until you feel OK again.

It's an offence to drive a car if your ability to drive safely is affected. It's your responsibility to decide if it's safe to drive. If you're in any doubt, do not drive.

Talk to your doctor or pharmacist if you're unsure whether it's safe for you to drive while taking or using terbinafine. GOV.UK has more information on the law on drugs and driving.

Can I drink alcohol while using or taking terbinafine?

Yes, you can drink alcohol while using or taking terbinafine.

Is there any food or drink I need to avoid?

Terbinafine tablets may increase the effects of caffeine. Having too much caffeine can give you headaches, stop you sleeping, make you feel agitated and it can make you pee more.

It's a good idea to avoid having too much caffeine while taking the tablets. Caffeine is found in coffee, tea, colas, energy drinks and chocolate.

Other than this, you can eat and drink normally while using or taking terbinafine.

Can lifestyle changes help with fungal skin infections?

If you have a fungal skin infection, these tips may help:

  • always wash your hands after treating the infection to stop it from spreading
  • do not scratch the area with the infection, as this can make the infection worse
  • keep the affected areas of your skin clean and dry
  • do not share towels, bedsheets or combs with other people as you could spread the infection to them
  • wash towels and bedding regularly

Read more about what you can do if you have:

Page last reviewed: 24 March 2023
Next review due: 24 March 2026