Antifungal Therapy

What is it?

Antifungal therapy means using medicines to treat fungal infections. These infections most often affect the skin, hair and nails. The medicines work in one of two ways. Some kill the fungus, such as terbinafine. Others stop the fungus growing so your body's immune system can clear it.

There are several families of antifungal medicine, including polyenes, azoles and echinocandins. Azoles work by blocking the fungus from making part of its outer layer (its cell membrane). Because the families work differently, the right one depends on the type of fungus and where the infection is.

Antifungals come as creams, paints that you brush onto the nail, and tablets. Most need a pharmacist or doctor to choose the right product for you.

What is it used for?

Antifungals are used for fungal infections such as athlete's foot, ringworm and fungal nail infection. A fungal nail infection (onychomycosis) is common and is about half of all nail disease.

The best proof of benefit is for fungal infection of the toenails in adults. Both terbinafine tablets and azole tablets clear toenail infections far more often than a dummy treatment. Terbinafine is commonly the first medicine prescribed for skin and nail infections, and one review names it the treatment of choice for nails. Nail paints such as efinaconazole also work better than a dummy paint, though they are less likely to clear the nail completely.

For athlete's foot and other ringworm of the skin, creams are the usual treatment.

For ringworm of the scalp (tinea capitis), which mostly affects children, topical treatment alone is generally not enough. A doctor usually prescribes tablets as well as a topical treatment. In children with a fungal nail infection, itraconazole and terbinafine have cleared the infection in many cases. Complete cure was 70.4 to 90.0 per cent with itraconazole and 57.1 to 100 per cent with terbinafine.

Is it right for me?

Antifungals suit people with a confirmed or suspected fungal infection of the skin, hair or nails. The best choice depends on your age and general health, the type of fungus, how many nails are affected and how much of each nail is involved.

Tablets are more likely to cure a toenail infection than paints or creams. They also carry more risks and need closer monitoring. Before you start tablets, you should have a laboratory test to confirm the fungus, and your doctor should weigh up the benefits and risks for you. People with a weakened immune system are more likely to need tablets.

Tablets may not be suitable if you:

• have liver or kidney disease (terbinafine should not be taken with severe liver disease)
• are pregnant or breastfeeding
• take other medicines, because azole antifungals interact with many of them

Tell your doctor or pharmacist about all your medicines, any allergies, and any liver or kidney problems.

If you have diabetes or a weakened immune system, see your GP about a fungal nail infection, because foot problems can be more serious. Children can have some antifungals, but they need doses set for their age, so ask a pharmacist or GP first.

What happens?

Antifungal therapy is a course of medicine, not a set of treatment sessions. A pharmacist or GP advises which product suits you, and your doctor tells you how long to take it. Your podiatrist can help you decide who to see.

For athlete's foot and other ringworm of the skin, you usually need a cream for 1 to 2 weeks. Keep using it for 2 weeks after the signs of infection have gone. Most creams only slow the fungus down rather than kill it, so stopping early lets it return.

Nail paints are brushed onto the affected nail. They are typically used for 6 to 12 months, and it can take several months before you see any improvement. Don't stop early because progress looks slow.

Terbinafine tablets for a nail infection may be taken for up to 3 months, sometimes longer. If you take terbinafine tablets, you should have a liver check before you start and another check 4 to 6 weeks after starting.

For ringworm of the scalp, your doctor chooses the tablet by the type of fungus. Family members who have no signs of infection are usually given an antifungal shampoo, not tablets. Tablets are for people who actually have signs.

If the treatment isn't working, go back to the doctor who prescribed it. They may extend the course or switch to a different medicine.

How well does it work?

For toenail infections, tablets give the best chance of clearing the infection. In one comparison, taking terbinafine continuously for 24 weeks cleared the fungus more often than itraconazole or fluconazole, while 12 weeks did not.

Nail paints and lacquers are gentler. But the chance of a complete cure is relatively low, so partial clearing is more likely than a fully clear nail.

Nails grow slowly. A nail looks better only as healthy nail grows out, so it takes months to see the final result. Your results can also depend on your age and general health, the type of fungus, the number of nails affected and how much of each nail is involved.

It isn't yet clear whether laser treatment works for toenail fungus.

Risks and side effects

Side effects from antifungals are usually mild and don't last long. Nail paints and creams mostly cause skin reactions where they are applied. Tavaborole solution, for example, is more likely than a dummy paint to cause these reactions.

Some risks are more serious:

• Liver problems. Serious liver injury from terbinafine tablets is unusual, with a chance of less than 1 in 1,000. A blood test at 4 to 6 weeks can miss it, so it matters that you know the warning signs (listed at the end of this page). Some people taking ketoconazole tablets had serious liver problems that led to death or the need for a liver transplant.
• Heart rhythm changes. Ketoconazole tablets can cause changes in the heart's electrical activity, which can lead to life-threatening irregular heartbeats.
• Allergic and skin reactions. Rarely, an antifungal can cause an allergic reaction or a severe skin reaction.
• Interactions. Azole antifungals interact with many medicines, so your prescriber or pharmacist should review everything you take.

Afterwards

Take the full course your prescriber sets, even if the nail or skin looks better sooner. For nail infections, don't expect the nail to look clear straight away. Improvement shows as new healthy nail grows from the base.

If you aren't improving, go back to your doctor. They may extend the treatment or prescribe a different antifungal.

If a treatment hasn't helped or the problem comes back, see a doctor, because the problem may not be a fungal infection.

When to see a podiatrist

Book an appointment if

You think you have athlete's foot, ringworm or a fungal nail infection and want advice on which treatment suits you. Also book if a treatment hasn't helped or the problem keeps coming back, because it may not be fungal. If you have diabetes or a weakened immune system and a fungal nail infection, see your GP. If you are pregnant or breastfeeding, or the treatment is for a child, talk to a doctor or pharmacist before using any antifungal.

Seek prompt assessment if

If you have swelling of your face, neck or tongue, or trouble breathing after starting an antifungal, stop the medicine and call your local emergency number. If you get peeling or blistering skin, stop the medicine and see your GP or another doctor today. If your GP can't see you today, go to an urgent care clinic or an after-hours GP. If you notice dark urine, yellow skin or eyes, belly pain or loss of appetite while taking an antifungal, contact your doctor or pharmacist promptly, because these can be signs of liver effects. If you take ketoconazole tablets and have fainting, light-headedness, dizziness, or a fast or irregular heartbeat, tell your prescriber right away.

Frequently asked questions

Does laser work for toenail fungus?

It isn't yet clear. Laser and other device treatments haven't been shown to work as well as antifungal medicines, so they shouldn't be seen as proven alternatives. If you are thinking about laser, talk it over with your podiatrist or GP first.

Can I drink alcohol while taking antifungals?

Be careful. Fluconazole or itraconazole taken with alcohol can raise the risk of liver injury. Ask your doctor or pharmacist whether it is safe to drink alcohol with the medicine you've been given.

Should I see a pharmacist or my GP first?

Either can help. If you think you have a fungal infection, a pharmacist or GP can advise which antifungal is best for you. If you have diabetes or a weakened immune system, see your GP about a fungal nail infection. Tablets need a prescriber's input.

Further reading

• Common questions about ketoconazole NHS
• Antifungal medicines healthdirect