Other Brand Names

Interbi (tablet/krim), Lamisil, Termisil, terbinafin HCL, Haterbin, Meccaderma.

How It Works

Terbinafine is a synthetic antifungal medication that works by blocking sterol biosynthesis in fungi by inhibiting an enzyme called squalene epoxidase. Sterols are crucial for maintaining the stability and integrity of fungal cell membranes. By interfering with this process, terbinafine causes a deficiency of ergosterol and results in the accumulation of squalene within the fungal cell membrane, ultimately leading to the death of the fungal cell.

Indications

Terbinafine is primarily used for treating infections caused by dermatophytes, a group of fungi that commonly infect the nails and skin (tinea pedis, tinea cruris and tinea corporis), when oral treatment is necessary due to the infection’s location, severity, or extent.

Contraindications

• Known allergy to terbinafine

• Chronic or active liver disease

• Women who are breastfeeding

Side Effects

• Diarrhea or abdominal pain.

• Changes in taste or smell, or even a complete loss of taste or smell (these may improve after stopping the medication).

• Serious side effects, although rare, can occur. Seek medical attention if you notice vision problems, mood changes, such as depression, unexplained bleeding or bruising, unusual fatigue or tiredness, signs of kidney issues, like reduced urine output.

• Terbinafine can occasionally cause liver damage. If you experience any symptoms such as persistent nausea, vomiting, loss of appetite, severe abdominal pain, yellowing of the skin or eyes, or dark urine, seek immediate medical attention.

Types

Terbinafine is available in the forms of cream in 5, 10, and 15 mg tubes, and oral tablets

Dosage

• For adults, the typical recommended dosage is 250 mg per day, with the duration depending on the type of fungal infection: 2-6 weeks for tinea pedis (athlete’s foot), 2-4 weeks for tinea cruris (jock itch), 4 weeks for tinea corporis (body ringworm), and 6 weeks to 3 months for nail infections (longer for toenail infections).

• For children, treatment duration is usually 2 weeks. For tinea capitis (head fungal infection) in children over 1 year old, the dosage is 62.5 mg daily for children weighing 10-20 kg, 125 mg daily for children weighing 20-40 kg, and 250 mg daily for children weighing more than 40 kg

Safety

• Before using terbinafine, inform your doctor if you have any of the following conditions, such as immune system disorders, kidney or liver disease, and lupus
• This medication can increase your sensitivity to sunlight, so it's important to limit sun exposure. Wear protective clothing and use sunscreen when outdoors. If you experience sunburn or your skin becomes red or blistered, contact your doctor immediately.
• During pregnancy, terbinafine should only be used if it is clearly necessary. It is generally recommended to delay the treatment of fungal nail infections until after childbirth. Be sure to discuss the risks and benefits with your doctor.
• This medication is excreted in breast milk, so if you are breastfeeding, consult your doctor before using terbinafine.

Drug Interactions

• CYP2C9 and CYP3A4 inhibitors (e.g., cimetidine, fluconazole, amiodarone): The combination of terbinafine with these medications may increase its effects and plasma concentration.

• Rifampin may reduce the effects of terbinafine if they are taken together..

• Terbinafine can increase the effects of tricyclic antidepressants (TCAs, like desipramine), beta-blockers (e.g., atenolol), selective serotonin reuptake inhibitors (SSRIs, like escitalopram), and monoamine oxidase inhibitors (MAOIs, like rasagiline) by inhibiting the CYP2D6 enzyme.

• Terbinafine decreases the clearance of caffeine

• Terbinafine increases the clearance of cyclosporine.

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