Terbinafine cream is indicated for the treatment of the following dermatological infections: interdigital tinea pedis (Athlete’s foot), tinea cruris (jock itch) or tinea corporis (ring worm) due to susceptible organisms and planter tinea pedis (mocasin type) due to Trichophyton spp. Terbinafine tablet is indicated for the treatment of onychomycosis of the toe nail or finger nail due to dermatophytes and also by non-dermatophyte fungi.
Drugs for subcutaneous and systemic mycoses, Topical Antifungal preparations
Terbinafine, an Allylamine antifungal, inhibits biosynthesis of Ergosterol (an essential component of fungai cell membrane) via inhibition of Squalene Epoxidase enzyme. This results in fungal cell death primarily due to the increased membrane permeability mediated by the accumulation of high concentrations of Squalene but not due to Ergosterol deficiency. Depending on the concentration of the drug and the fungal species test in vitro, Terbinafine hydrochloride may be fungicidal. However, the clinical significance of in vitro data is unknown. Terbinafine has been shown to be active against most strains of the following microorganisms both in vitro and in clinical infections: Tricophyton Mentagrophyte, Trichophyton Rubrum.
Topical application: Terbinafine cream to affected areas once or twice daily for 1-2 weeks may be adequate for fungal infections of the skin but certain infections may require oral Terbinafine tablet therapy. Usual duration of treatment of Terbinafine cream: In Tinea corporis and Tinea cruris: 1-2 weeks. In Tinea pedis: 2-4 weeks (One week of treatment will normally suffice if the cream is applied twice daily.). In Cutaneous candidiasis: 1-2 weeks In Pityriasis (tinea) versicolor: 2 weeks. To prevent relapses in fungal infection, treatment should be continued for a adequate length of time. To apply Terbinafine cream clean and dry the affected areas thoroughly and apply the cream once or twice a day to the affected skin and surrounding area in a thin layer and rub in lightly. In the case of intertriginous infections the application may be covered with a gauze strip, especially at night. Oral administration: Terbinafine tablet is essential for hair or nail infections: The usual oral dose: Terbinafine 250 mg daily for 2 to 12 weeks depending upon the infection. Finger nail onychomycosis: Terbinafine 250 mg once daily for 6 weeks. Toe nail onychomycosis: Terbinafine 250 mg once daily for 12 weeks.
In vivo studies have shown that terbinafine is an inhibitor of the CYP450 2D6 isozyme. Drugs predominantly metabolized by the CYP450 2D6 isozyme include the following drug classes: tricyclic antidepressants, selective serotonin reuptake inhibitors, beta-blockers, antiarrhythmics class 1C (e.g., flecainide and propafenone) and monoamine oxidase inhibitors Type B. Co-administration of terbinafine should be done with careful monitoring and may require a reduction in dose of the 2D6-metabolized drug.
Hypersensitivity to Terbinafine or any of the excipients in the preparation Terbifine cream is for external use only. Contact with eyes should be avoided.Good general hygiene is necessary in conjunction with the use of Terbinafine in order to prevent reinfection (eg. from underwear, socks,shoes etc). Terbinafine tablet is not recommended for patients with chronic or active liver disease. Before prescribing terbinafine, pre-existing liver disease should be assessed. Hepatotoxicity may occur in patients with and without pre-existing liver disease. Pretreatment serum transaminase (ALT and AST) tests are advised for all patients before taking terbinafine tablets.
Terbinafine Tablet: Abdominal discomfort, anorexia, nausea, diarrhoea, headache, rash and urticaria occasionally with arthralgia or myalgia. Less frequently taste disturbance. Rarely liver toxicity, photosensitivity, serious skin reactions etc. Terbinafine Cream: Redness, itching, or stinging; rarely allergic reactions.
Terbinafine tablet: There are no adequate and well controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, and because treatment of onychomycosis can be postponed until after pregnancy is completed, it is recommended that terbinafine not be initiated during pregnancy. After oral administration, terbinafine is present in breast milk of nursing mothers. Treatment with terbinafine in not recommended in nursing mothers. Terbinafine cream: Foetal toxicity and fertility studies in animals suggest no adverse effects. There is no clinical experience with terbinafine in pregnant women; therefore, unless the potential benefits outweigh any potential risk, terbinafine should not be administered. Terbinafine is excreted in breast milk and therefore mothers should not receive terbinafine treatment whilst breast-feeding.
Clinical experience regarding overdose with terbinafine tablets is limited. Doses up to 5 gm (20 times the therapeutic daily dose) have been taken without inducing serious adverse reactions. The symptoms of overdose included nausea, vomiting, abdominal pain, dizziness, rash, frequent urination, and headache.
Store in a cool and dry place, below 30°C, protect from light.