Medication

Butenafine

Butenafine is an over-the-counter antifungal cream that kills the fungus behind ringworm and athlete's foot rather than just slowing it. It works like terbinafine and needs a similarly short course.
At a Glance

Butenafine, sold as Lotrimin Ultra, is a close chemical cousin of terbinafine. It kills dermatophytes — the ringworm family — instead of just holding them still, so courses are short: one to two weeks for most rashes, and once a day rather than twice. It is a genuinely good over-the-counter option and a sensible substitute when terbinafine cream is out of stock. Like terbinafine, it is not the drug for a Candida rash in a skin fold; an azole cream is better there.

Key Facts

Drug ClassTopical benzylamine antifungal (works like the allylamines, such as terbinafine)
Other NamesLotrimin Ultra, Mentax, Lotrimin AF Athlete's Foot Cream (some packs), butenafine hydrochloride 1%
Prescription OnlyNo. The 1% cream is over the counter; the same 1% is also sold as the prescription brand Mentax.
Typical CourseOnce a day for 2 weeks for ringworm, jock itch or tinea versicolor; once a day for 4 weeks, or twice a day for 1 week, between the toes
CostAbout $8 to $16 for a 12 g to 24 g tube. More per gram than clotrimazole, but you use it for a fraction of the time.

How It Works

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Fungi need ergosterol to build their outer membrane. Butenafine blocks squalene epoxidase, an enzyme near the start of that assembly line. Two things then happen at once: the fungus runs out of ergosterol, and a substance called squalene builds up inside it to toxic levels. That second effect is what kills the fungus outright rather than simply stopping it dividing.

This is the same mechanism terbinafine uses, which is why the two behave so similarly. It is very effective against dermatophytes, the fungi behind ringworm, jock itch and athlete's foot. It also works well enough against Malassezia to be approved for tinea versicolor. What it does not do well is Candida, the yeast in most skin-fold rashes — for those, clotrimazole or miconazole is the better pick.

What It Treats

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Strong evidence
Butenafine is chemically close to terbinafine and kills dermatophytes rather than slowing them, giving short, effective courses for ringworm on the body.
Strong evidence
Butenafine is a benzylamine closely related to the allylamines, fungicidal against dermatophytes, with cure rates for tinea pedis comparable to terbinafine.

Who It's For & Who It's Not

Who it's for

Athlete's foot, especially between the toes.

Ringworm and jock itch on the body.

Tinea versicolor on a limited area.

Anyone who wants a short course — one to two weeks rather than four.

Who it's not for

Rashes in skin folds that are likely to be Candida. It does not cover that yeast well.

Fungal nails, which no cream can reach through the nail plate.

Scalp ringworm, which needs a tablet.

Anyone who has reacted to terbinafine cream — the two are chemically related enough that a reaction to one makes the other a poor choice.

How to Take It

How much and how often
  • A thin layer once a day for most rashes. For athlete's foot between the toes there are two labelled options: once a day for four weeks, or twice a day for one week. Both work; the one-week version suits people who will not keep going for a month.
Where to put it
  • On the rash and about an inch (two centimetres) beyond its edge. For feet, cover the sole, the sides and every toe web, not just the area that itches. Fungus is present on skin that still looks normal.
Keep going after it looks clear
  • Even with a short course, finish the days you were told to. The skin usually looks normal several days before the fungus is gone.

What to Avoid

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Steroid creams on the same rash unless a doctor has said so. Steroid alone makes fungal rashes spread and hard to identify.

Eyes, mouth and vagina — external skin only.

Covering the treated area with plastic or an airtight dressing.

Untreated shoes and socks, if you are treating athlete's foot. Powder or spray the insides while you treat the skin.

There are no interactions with medicines taken by mouth, and no issue with alcohol or sun. Very little is absorbed through the skin.

Side Effects

Common and expected
  • Burning or stinging when it goes onItching or redness at the site Worsening of the rash in a small number of people, usually irritation rather than infection
  • Most people have no side effects. Local reactions are reported in around 2 in 100.
Tell your doctor
  • Irritation that keeps building after the first few daysNo improvement after two weeks A rash that spreads beyond where you are applying it A skin-fold rash that is not responding — this often means Candida, and a different cream is needed
Stop and get care
  • Hives, swelling of the face or lips, or trouble breathingBlistering or peeling of the treated skin

How Long Until It Works

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Days two to four

Itching and burning ease.

Week one

Redness and scale visibly improve. Between the toes, the soggy white skin firms up.

Weeks two to four

A ringworm or jock itch patch is usually clear by two weeks. Athlete's foot on the sole is slower and may need the full four.

After you stop

Skin keeps improving for one to two weeks after the last application, because butenafine stays in the skin at active levels for a while. That is why the short courses work.

No change at two weeks

Worth reconsidering — either the diagnosis is wrong or it is a yeast rather than a dermatophyte.

The marks afterwards

Lighter or darker patches can persist for weeks to months where the rash was, more visibly on brown and Black skin. That is pigment settling, not infection.

What Happens When You Stop

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You stop at the end of the labelled course, and the drug keeps working in the skin for a while afterwards, so improvement often continues for another week or two.

Ringworm and jock itch treated properly usually stay away. Athlete's foot is the exception — it returns for a lot of people, because shoes hold the fungus and feet keep getting damp. An antifungal powder in the shoes a couple of times a week is what prevents that, not more cream.

Tinea versicolor comes back in most people over the following year or two, usually in warm weather. That is expected and does not mean anything went wrong.

Nothing rebounds and there is nothing to taper.

FAQ+
Is Lotrimin Ultra the same as Lotrimin AF?No, and this catches people out. Lotrimin Ultra is butenafine. Lotrimin AF cream is usually clotrimazole and the AF powders and sprays are usually miconazole. Same brand family, different drugs and different courses.
Butenafine or terbinafine?They work the same way and are about equally effective. Choose whichever is available or cheaper. Terbinafine has more published trials behind it; butenafine has a labelled once-daily option that some people find easier.
Why is the course so much shorter than clotrimazole?Because butenafine kills the fungus rather than just stopping it growing, and it stays active in the skin for days after you stop applying it.
Can I use it on a rash under my breast or in my groin fold?Jock itch on the inner thigh, yes. A raw, red rash deep in a moist fold is more likely Candida yeast, which butenafine does not cover well — clotrimazole or miconazole is the better choice.
Will it fix a fungal toenail?No. No cream penetrates the nail plate.
Can I use it on my face?On a fungal rash, yes, away from the eyes. Because several non-fungal face rashes look similar, it is worth being reasonably sure first.
Is it safe in pregnancy?Very little is absorbed through the skin. There is less published pregnancy data on butenafine than on clotrimazole, so if you are pregnant, clotrimazole is the better-studied choice.
Does it treat tinea versicolor?Yes, once a day for two weeks on a limited area. For a whole back, a ketoconazole or selenium sulfide wash is far more practical.