Lamisil cream (Terbinafine)

What Is Lamisil?

Lamisil cream is an effective topical treatment for a range of fungal infections affecting the skin and nearby areas. In UK practice, terbinafine cream is commonly used for superficial fungal skin infections when a topical antifungal is appropriate. It is generally well tolerated, with a low rate of reported side effects. The main active ingredient in the cream is terbinafine. This substance belongs to the allylamine group and has a broad range of antifungal effects. Even at relatively low concentrations, it has a fungicidal effect against most dermatophytes and dimorphic fungi.

Composition and Active Ingredients

Lamisil formulations for topical use, such as creams or gels, contain terbinafine hydrochloride at a concentration of 1% w/w. One gram of the cream contains terbinafine hydrochloride 10 mg, equivalent to 8.8 mg of terbinafine. Other ingredients may include cetyl alcohol, stearyl alcohol and benzyl alcohol, which help give the product its texture and stability.

Terbinafine works by inhibiting squalene epoxidase, an enzyme that is essential for ergosterol synthesis in fungal cell membranes. This leads to fungal cell death and helps treat infections such as athlete's foot and onychomycosis. Less than 5% of the dose is absorbed after application to the affected area of skin, so absorption into the bloodstream is negligible.

Uses

The medicine may have both fungicidal and fungistatic effects. It also has a long-lasting effect, which can help patients not only treat the infection but also reduce the risk of it coming back after a short course of treatment.

Lamisil (terbinafine) is indicated for the topical treatment of the following skin infections: tinea (pityriasis) versicolor due to Malassezia furfur (formerly Pityrosporum ovale), tinea pedis (athlete's foot), tinea corporis (ringworm), and tinea cruris (jock itch) due to Trichophyton rubrum, Trichophyton mentagrophytes, or Epidermophyton floccosum. The diagnosis should be confirmed either by culture (except Malassezia furfur, formerly Pityrosporum ovale) or by examination of skin scrapings from infected tissue in a potassium hydroxide solution.

Lamisil in the Treatment of Fungal Infections

Terbinafine specifically inhibits the early stage of sterol biosynthesis in fungal cell membranes. This leads to a deficiency of ergosterol and an intracellular build-up of squalene, which causes fungal cell death. Terbinafine works by inhibiting the squalene epoxidase enzyme in the cell membrane. As this enzyme is not part of the cytochrome P450 system, terbinafine does not affect hormone metabolism in the human body.

Lamisil cream is used to treat various fungal skin infections, including tinea pedis (athlete's foot), tinea cruris (jock itch) and tinea corporis (ringworm).

For adults and children aged 12 and over, Lamisil cream should be applied 1-2 times a day depending on the severity of the infection.

The duration of treatment depends on the severity of the condition.

• Interdigital toe web infections and/or dermatophyte infections of the torso - the cream should be used once a day for 1 week.
• Skin candidiasis - the cream should be used 1-2 times daily for 1 week.
• Multicoloured lichen - the cream should be used 1-2 times daily for 2 weeks.

Older patients do not need any dose adjustment. Clinical experience in children under 12 years of age is limited, so the medicine should not be used in this age group.

The cream should be applied to the affected area and the surrounding skin after the area has been cleaned and dried thoroughly. It is important to avoid contact with the eyes, nose, mouth and other mucous membranes. If irritation occurs, stop using the cream. Using it consistently as directed is important for effective treatment, even if symptoms start to improve before the full course is finished.

Lamisil in the Treatment of Yeast Infections

Lamisil cream may be used for some fungal skin infections. However, if penile thrush is suspected, treatment should follow current clinical guidance, as other antifungal medicines are more commonly used for candidal balanitis. Applied to the affected skin, treatment may help reduce irritation and support clearance of the infection.

Lamisil cream is usually applied once or twice daily. However, if yeast nappy rash is suspected, other antifungal treatments are more commonly used in UK practice. If there is no improvement, the condition should be reviewed by a doctor or pharmacist.

Precautions

Lamisil is not for use in the eyes, by mouth or inside the vagina. The cream is for external use only. In the UK, patients should be advised to use Lamisil as directed by their doctor.

Noticeable relief is usually seen two to three days after starting treatment. Irregular use or stopping treatment too early may allow the infection to return.

If there is no clear improvement after two weeks of treatment, contact your doctor. Additional dose adjustments may be needed.

Allergy Warnings

Lamisil (terbinafine) is contraindicated in people with known or suspected hypersensitivity to terbinafine or any of its other ingredients. Tell your doctor if the application area becomes more irritated or shows possible signs of sensitisation, such as redness, itching, burning, blistering, swelling or oozing.

Health Conditions Warnings

Terbinafine may be present in breast milk. For this reason, the medicine should not be used by women who are breastfeeding. Pregnant women should also avoid using Lamisil.

Lamisil 1% contains 11.3% v/v alcohol. If irritation or sensitivity develops, treatment should be stopped and appropriate treatment started. Lamisil may irritate the eyes. If it accidentally gets into the eyes, rinse them thoroughly with running water and consult a doctor if symptoms continue.

Patients in the UK should avoid covering the affected areas with dressings unless their doctor advises otherwise.

There is no experience of overdose with topical terbinafine formulations. However, the alcohol content (11.3%) of the cream should be taken into account.

Terbinafine Side Effects

In most clinical cases, side effects are rare and do not need medical treatment. Possible side effects include:

• Local symptoms such as itching, peeling or burning of the skin, pain and irritation at the application site, pigmentation and erythema. These mild symptoms should be distinguished from hypersensitivity reactions, including rash, which may require treatment to be stopped.
• If the cream accidentally gets into the eyes, terbinafine hydrochloride may cause eye irritation.
• Pain at the application site.
• Irritation at the application site.
• Rarely reported worsening of symptoms of the fungal infection.

In clinical trials, none of the 262 patients treated with Lamisil (terbinafine) stopped treatment because of adverse events. In patients treated with Lamisil (terbinafine), reactions thought to be possibly, probably or definitely related to treatment included skin disorder (1.9%), application site reactions (burning or irritation) (1.5%), and pruritus (1.1%). These events were seen only in patients with tinea cruris: skin discolouration, hyperpigmentation (3/36), skin exfoliation (1/36), and contact dermatitis (1/36).

Interaction with Other Medicines

Potential interactions between Lamisil (terbinafine) and other medicines have not been systematically evaluated.

After Using Lamisil

After using Lamisil cream, it is important to store and dispose of it properly.

Storage

Lamisil cream should be stored in its original packaging to protect it from light and moisture. Keep the tube tightly closed and out of the reach of children. Do not use the cream after the expiry date shown on the packaging. Once opened, an aluminium tube can typically be used for up to four months, while a laminated tube has a shelf life of one month.

Disposal

When disposing of Lamisil cream, do not put it in household waste or pour it down the drain, as this can harm the environment. Instead, in the UK, ask your pharmacist about the proper way to dispose of it. Unused or expired medicines should be returned to a pharmacy for safe disposal to help protect the environment.