Indications

Xfin Tablet: Indicated for the treatment of onychomycosis (fungal infection of the nail) of the toenail or fingernail caused by dermatophytes (Tinea Unguium).

Xfin Granules: Indicated for the treatment of Tinea Capitis (ringworm of the scalp).

Xfin Cream: Used for fungal infections of the skin caused by various fungi, including Trichophyton species, Microsporum canis, and Epidermophyton floccosum. It is also used for yeast infections of the skin caused by Candida and for Pityriasis (tinea) versicolor.

Xfin 1% Spray: Indicated for the treatment of tinea infections of the skin and Pityriasis (tinea) versicolor.

Pharmacology

Terbinafine is an allylamine antifungal.It works by inhibiting the enzyme Squalene Epoxidase, which is a key step in the biosynthesis of Ergosterol, an essential component of the fungal cell membrane. This inhibition leads to a buildup of Squalene within the fungal cells, causing increased membrane permeability and eventually leading to fungal cell death.

Dosage & Administration

Terbinafine Tablet:

• Fingernail onychomycosis: 250 mg once daily for 6 weeks.
• Toenail onychomycosis: 250 mg once daily for 12 weeks.

Terbinafine Granules:

• Body Weight <25 kg: 125 mg/day for up to 6 weeks.
• Body Weight 25-35 kg: 187.5 mg/day for up to 6 weeks.
• Body Weight >35 kg: 250 mg/day for up to 6 weeks.

Terbinafine Cream:

• Apply a thin layer to the affected and surrounding areas once or twice daily.
• Tinea corporis/cruris: 1 to 2 weeks.
• Tinea pedis: 1 week.
• Cutaneous candidiasis: 2 weeks.
• Pityriasis versicolor: 2 weeks.
• If no improvement is seen after two weeks, the diagnosis should be re-evaluated.

Terbinafine 1% Spray:

• Tinea pedis: Once a day for 1 week.
• Tinea corporis/cruris: Once a day for 1 week.
• Pityriasis versicolor: Twice a day for 1 week.

Interaction

Terbinafine can inhibit the enzyme CYP450 2D6. Co-administration with drugs metabolized by this enzyme (e.g., tricyclic antidepressants, beta-blockers, certain antiarrhythmics) should be done with caution, as it may require a dose reduction of the other drug.

Contraindications

Terbinafine tablets and cream are contraindicated in individuals with a known hypersensitivity to terbinafine.

Side Effects

Common side effects are generally mild and temporary, and include gastrointestinal issues (diarrhea, nausea, abdominal pain), rashes, hives, itching, and taste disturbances. More severe, but rare, side effects include liver injury (sometimes leading to liver failure or death), serious skin reactions (e.g., Stevens-Johnson Syndrome), severe neutropenia, and allergic reactions.

Pregnancy & Lactation

Terbinafine tablets are not recommended during pregnancy as there are no adequate studies in pregnant women. Treatment of onychomycosis can be postponed until after pregnancy. After oral administration, terbinafine is present in breast milk, so it is not recommended for nursing mothers. For topical preparations, a doctor should be consulted before use in pregnant or breastfeeding women.

Precautions & Warnings

• Tablets: Rare cases of liver failure, some fatal, have occurred. The drug should be discontinued if there is any sign of liver injury. Rare cases of serious skin reactions have also been reported; discontinue if a progressive skin rash occurs. It is not recommended for patients with chronic or active liver disease. Pretreatment blood tests for liver enzymes are advised for all patients before starting tablets.
• Cream: For external use only. Avoid contact with the eyes.

Use in Special Populations

• Pediatric use: The safety and efficacy of terbinafine tablets have not been established in pediatric patients.
• Elderly: No evidence suggests a need for different dosages or that side effects are different from younger patients.

Overdose Effects

Clinical experience with overdose is limited. Doses up to 5 gm have been taken without serious adverse reactions. Symptoms may include nausea, vomiting, abdominal pain, dizziness, and headache.

Therapeutic Class

Terbinafine is classified as an Other Antifungal preparation and Topical Antifungal preparation.

Storage Conditions

Store in a cool and dry place, below 30°C, and protected from light.