Terbinafine

What is Terbinafine?

Ringworm is a really common fungal infection that causes a red or silvery rash on the affected area of skin. Estimates suggest around 10-20% of people will get ringworm at some point during their life.^[1]
It’s also known by other names depending on the area it affects – ringworm on the foot is commonly called athlete’s foot, for example.

Terbinafine is an antifungal medicine that’s used to treat skin infections caused by fungi, including athlete’s foot and ringworm. Antifungals target and kill the fungus responsible for causing infections, and stop them from growing and spreading further.

Terbinafine is the generic version of the brand-name treatment Lamisil. This means it contains the same active ingredients as Lamisil and works in the same way, but it’s usually a bit cheaper. Terbinafine contains the active ingredient terbinafine hydrochloride, and comes as a cream or tablets.

How does Terbinafine work?

The active ingredient in terbinafine is terbinafine hydrochloride, a type of antifungal medicine that we call allylamines. These medicines kill the fungi responsible for infections by disrupting the synthesis of ergosterol in the fungal cells.^[2]

Ergosterol is a critical component of fungal cell membranes, and is responsible for their permeability.^[3]
Without ergosterol the membrane becomes unstable and can ‘leak’, ultimately killing the cell^[4]
.This prevents the infection growing any further, and should eventually clear it up.

What doses does Terbinafine come in?

Generic terbinafine comes as tablets that contain 250 mg of terbinafine hydrochloride, or a cream that contains 10mg of terbinafine hydrochloride per gram.

Lamisil, the brand-name version of terbinafine, is also available as a topical spray or gel that you apply directly to the affected area of skin.

How to use Terbinafine

You should always follow the instructions of your clinician or pharmacist when you’re using terbinafine. But typically, if you’re using terbinafine cream:

• Apply it 1-2 times a day.
• Clean your hands and the affected area, and make sure they’re completely dry.
• Squeeze a small amount of cream onto your finger.
• Apply a thin layer of cream to the affected skin and surrounding area.
• Gently rub the cream into your skin.
• Cover the area with a fresh strip of gauze if you’re using it for athlete’s foot.
• Wash your hands after applying it.

If you’re using terbinafine tablets:

• Swallow one 250mg tablet whole with a drink of water.
• You can take your terbinafine with or without food.

How long does it take Terbinafine to work?

How long terbinafine takes to work depends on the condition you’re using it to treat, and the type of terbinafine treatment you’re using.

Here are the usual treatment lengths:

• Tablets for ringworm: 2-4 weeks
• Tablets for athlete’s foot: 2-6 weeks^[1]
• Cream for ringworm: 1-2 weeks
• Cream for athlete’s foot: 1 week^[2]

If you’re using terbinafine tablets, you might find your symptoms don’t clear up until a few weeks after you’ve stopped your course of treatment.^[3]

If you’re using terbinafine cream, the infection can start to improve within a few days of use, but you should make sure to keep using the cream regularly for the duration of your treatment. It usually takes around four weeks for your skin to heal after the infection has cleared. If you haven’t noticed any improvement after using terbinafine cream for two weeks, speak to your clinician.^[4]

What should I do if I make a mistake taking Terbinafine?

If you forget to use or take your terbinafine at the right time, don’t worry. You can just take your tablet or apply your cream as soon as you remember. If it’s almost time for your next dose, just wait and take the upcoming dose as normal. Don’t take another tablet or apply more cream to make up for a missed dose. However, it’s important to do your best to remember your treatment, as missing a dose can run the risk of the infection returning or worsening.

If you use too much terbinafine cream, scrape off some of the excess cream. If you swallow the cream, or take too many terbinafine tablets, seek medical assistance immediately and take the medicine and information leaflet with you if you can. Symptoms of terbinafine overdose can include headaches, nausea, dizziness and abdominal pain.