Terbinafine Tablets USP 250mg
Each uncoated tablet contains Terbinafine Hydrochloride USP equivalent to Terbinafine 250mg.
Terbinafine is an allylamine antifungal indicated for the treatment of onychomycosis of the toenail or fingernail due to dermatophytes, ringworm infections (including tinea pedis, cruris and corporis) where oral therapy appropriate (due to site, severity or extent).
Terbinafine is an allylamine which has a broad spectrum of antifungal activity. At low concentrations Terbinafine is fungicidal against dermatophytes, moulds and certain dimorphic fungi. The activity versus yeasts is fungicidal or fungistatic depending on the species.
Terbinafine interferes specifically with fungal sterol biosynthesis at an early step. This leads to a deficiency in ergosterol and to an intracellular accumulation of squalene, resulting in fungal cell death. Terbinafine acts by inhibition of squalene epoxidase in the fungal cell membrane. The enzyme squalene epoxidase is not linked to the cytochrome P450 system.
Dosage and Administration
An oral dose of 250mg is given once daily for 2-4 weeks for tinea cruris; treatment may be continued for up to 6 weeks for tinea pedis infections; a 4 week course is used in tinea corporis infection.
Dermatophyte infections of the nails are treated with the equivalent of Terbinafine 250mg orally once daily for 6 to 12 weeks although longer treatment may be necessary in toe-nail infections.
In children of over 1 year of age, bod- weight 10-20kg, 62.5mg once daily; body-weight 20-40kg, 125mg once daily; body-weight over 40kg, 250mg once daily.
Mode of administration: For oral use.
TERBINAFORCE-250 is contraindicated in individuals with a history of allergic reactions to oral Terbinafine because of the risk of anaphylaxis or any excipients of this medication.
Special warning and precautions for use
TERBINAFORCE-250 contains Lactose. Patients with rare hereditary problems of galactose intolerance, or glucose-galactose malabsorption should not take this medicine.
Terbinafine is not recommended for patients with chronic or active liver disease. Before prescribing Terbinafine, any pre-existing liver disease should be assessed. Hepatotoxicity may occur in patients with and without pre-existing liver disease.
Taste disturbance, including taste loss, has been reported with the use of Terbinafine. Taste disturbance can be severe, may be prolonged or may be permanent. Discontinue Terbinafine if taste disturbance occurs.
Smell disturbance, including loss of of smell, has been reported with the use of Terbinafine. Smell disturbance may be prolonged or may be permanent. Discontinue Terbinafine if smell disturbance occurs.
Depressive symptoms have been reported with Terbinafine use. Prescribers should be alert to the development of depressive symptoms.
Severe netropenia has been reported. If the netrophil count is ≤1,000 cells/mm3, Terbinafine should be discontinued.
Stevens-Johnson syndrome and toxic epidermal necrolysis have been reported with oral use of Terbinafine. If progressive skin rash occurs, treatment with Terbinafine should be discontinued.
Precipitation and exacerbation of cutaneous and systematic lupus erythematosus have also been reported.
Interaction with other medicinal products and other forms of interaction
Plasma concentrations of Terbinafine may be increased by drugs that inhibit its metabolism by cytochrome P450, such as cimetidine, and decreased by drugs that induce cytochrome P450 enzymes, such as rifampicin.
Menstrual disturbances including breakthrough bleeding have been reported in patients taking oral contraceptives and Terbinafine.
Terbinafine has been shown in vitro to inhibit metabolism mediated by the cytochrome P450 isoenzyme CYP2D6. Hence it may affect the plasma concentrations of drugs predominantly metabolized by this enzyme such as tricyclic antidepressants, beta blockers.
Pregnancy and lactation
Use in pregnancy: Pregnancy category B. should be used during pregnancy only if clearly needed.
Use in lactation: Terbinafine is excreted in breast milk and therefore mothers should not receive Terbinafine whilst breast-feeding.
Effects on ability to drive and use machines
Patients who experience dizziness as an undesirable effect should avoid driving vehicles or using machines.
Abdominal discomfort, anorexia, nausea, diarrhea, headache, rash and urticaria occasionally with arthralgia or myalgia are some of the undesirable effects; less commonly taste disturbance; rarely liver toxicity (including jaundice, cholestasis and hepatitis) have been reported, in such cases discontinue treatment, Angioedema, dizziness, malaise, paraesthesis, hypoaesthesia, photosensitivity, serious skin reactions (including Stevens-Johnson syndrome and toxic epidermal necrolysis), discontinue treatment if progressive skin rashes occurs; Very rarely reported side effects are: psychiatric disturbances, blood disorders (including leucopenia and thrombocytopenia), lupus erythematosus like-effect and exacerbation of psoriasis.
Doses up to 5 grams have been reported without including serious adverse reactions. The symptoms of overdose included nausea, vomiting, abdominal pain, dizziness, rash, frequent urination and headache. The recommended treatment of overdosage consists in eliminating the drug, primarily by the administration of activated charcoal and giving symptomatic supportive therapy if needed.