This information is for people who have a fungal nail infection. It tells you about terbinafine tablets, a treatment used for fungal nail infections. It is based on the best and most up-to-date research.
Do they work?
Yes. If you take terbinafine tablets you're more likely to get rid of your fungal nail infection than if you don't have any treatment. Terbinafine tablets seem to work better than other antifungal drugs.
What are they?
Terbinafine is an antifungal drug (a drug that kills fungi). It's used to treat infections that are caused by fungi, including those that affect fingernails and toenails. It doesn't change the way that damaged nails look. But, by stopping the fungus, it allows new nails to grow normally.
The brand name for terbinafine tablets is Lamisil.
You'll need to take terbinafine tablets every day for several weeks or months.  The minimum for a fingernail infection is about six weeks. For an infected toenail, three months is more realistic. Some people need treatment for six months or more to get results.
Studies show that terbinafine is safe to take for most people. That includes people with diabetes or HIV, and people who have had a transplant. 
How can they help?
If you take terbinafine tablets every day for 12 weeks, there's a 6 in 10 chance you'll get rid of your fungal nail infection. 
If you take the drug for 24 weeks, you're even more likely to get rid of your fungal nail infection. Nearly 9 in 10 people who take terbinafine for 24 weeks get rid of their fungal nail infection. 
Terbinafine tablets appear to work better than itraconazole and griseofulvin tablets. 
How do they work?
Terbinafine kills the fungus that causes nail infections and makes nails look bad.  This allows new nails to grow normally.
Can they be harmful?
All antifungal tablets can cause diarrhoea, a rash, or breathing problems.  But not many people get these problems. They are usually mild and go away when you stop taking the tablets.
You may be slightly more likely to get side effects if you're older (over 60). One study found that among 30 people over 60 years old there were 18 reports of side effects.  These were classed as mild or moderate. And no one in the study stopped their treatment because of these side effects.
Sometimes people get more serious side effects. These are rare but it is important to know about them. The main issue is liver problems.Liver problems
Terbinafine can cause liver problems, so you'll need to have regular tests to make sure your liver is working normally. You should call your doctor straight away if you get any of the following symptoms: