Terbinafine oral

Indications: Finex tablets (Lamisil Tablets) are indicated for fungal infections where oral therapy is considered appropriate due to site, severity or extent of the infection. Finex is effective in infections caused by skin and nails dermatophytes such as Trichophyton (eg .: T. rubrum, T. mentagrophytes), and Epidermophyton floccosum Microsporum canis. oral Finex is indicated in the treatment of: tinea corporis, tinea cruris, and tinea pedis and skin infections caused by Candida yeasts (eg .: Candida albicans). Onychomycosis caused by dermatophyte fungi. The oral presentation is not effective in vaginal candidiasis and tinea versicolor. Applied topically, terbinafine quickly begins its action and effectiveness achieved in a short time. Human less than 5% of the applied dose is absorbed topically.

Properties: Finex is terbinafine, an allylamine with broad fungicidal activity against dermatophytes, yeasts and molds and certain dimorphic fungi. Its activity against yeasts may be fungicidal or fungistatic depending on the species. Terbinafine acts on the sterol biosynthesis which leads to a deficit of ergosterol and to an intracellular accumulation of squalene, with subsequent death fungal cell. Terbinafine inhibits squalene epoxidase in the fungal cell membrane. Terbinafine no interaction at the level of cytochrome P-450 in mammals. It not influences the metabolism of hormones or other drugs. Administered orally, terbinafine concentrates skin and nail at adequate levels for their fungicidal activity. A single oral dose of 250 mg terbinafine results in peak plasma concentrations of 0.97 mg / ml 2 hours after administration. The absorption half-life is 0.8 hours and the distribution half-life is 4.6 hours. Co-administration with food moderately affect the bioavailability, which despite dose adjustment is required. Terbinafine binds strongly to plasma proteins (99%). Rapidly diffuses through the dermis and concentrates in the stratum corneum lipophilic. It is excreted by the sebaceous secretion which achieves high concentrations in hair follicles, hair and sebum-rich skin. Terbinafine is distributed into the nail plate from the first weeks of therapy. Terbinafine rapidly and extensively metabolized in the liver by at least 7 isoenzymes. Metabolites have no antifungal activity and are excreted primarily in the urine. The elimination half-life is 17 hours. Although it was not observed any change in plasma concentrations age-dependent, the elimination rate may be reduced in patients with renal or hepatic impairment.

Dosage: 250 mg 1 time per day. In tinea pedis it is suggested: 2-6 weeks. Tinea corporis, cruris: 2-4 weeks. Cutaneous candidiasis: 2-4 weeks. Complete remission of signs and symptoms of infection may take several weeks beyond mycological cure. Onychomycosis: it suggests 6 to 12 weeks of treatment. Onychomycosis of hands: 6 weeks. Omicomicosis feet: 12 weeks is sufficient in most cases. Some patients with slow nail growth may require longer treatments. In onychomycosis clinical resolution is seen some months after therapy ended. In elderly: no dose adjustment is required. However, pre-existing impaired renal or hepatic function should be considered. Finex tablets are not indicated in children under 12 years old. Children> 40 kg: 250 mg 1 time per day. Finex cream can be applied 1 or 2 times a day, after cleaning and drying the affected area, spreading a thin layer on the skin. Duration of treatment tinea corporis, cruris: usually 1 week, 1 once a day. Tinea pedis: usually 1 week, 1 time per day. Cutaneous candidiasis: usually 1 week, 1 once a day. Tinea versicolor: usually 2 weeks, 2 times a day. Clinical improvement of symptoms usually occurs within a few days. Irregular use or premature discontinuation of treatment is accompanied by a risk of recurrence.

Side effects: Tablets: is generally well tolerated. Adverse effects are usually transient and of low magnitude: feeling of gastric fullness, loss of appetite, dyspepsia, nausea, mild abdominal pain, diarrhea, rash, urticaria, arthralgia, myalgia. They are also described, although with very low frequency, taste alterations usually recover after discontinuation of the drug; hepatobiliary dysfunction including rare cases of liver failure. Very rarely serious skin reactions have been reported, anaphylactic reactions, hematologic disorders such as neutropenia, agranulocytosis and thrombocytopenia. Cream: adverse reactions are rare: redness, itching or burning.

Precautions: Tablets: to present signs suggestive of liver dysfunction Finex treatment should be discontinued. Patients with stable chronic liver dysfunction should receive half the usual dose with a permanent monitoring of their condition. Patients with impaired renal function (creatinine clearance less than 50 ml / min. Or serum creatinine greater than 300 mmol / l) should receive half the dose. It is necessary to monitor patients receiving concomitant therapy with drugs metabolized by CYP2D6 isoenzyme it, as in the case of tricyclic antidepressants, beta blockers, selective inhibitors of serotonin reuptake inhibitors and monoamine oxidase type B is only for use Finex external. It is not intended for ophthalmic, oral or intravaginal use. Pregnancy and lactation: Clinical experience in pregnant women is very limited so that Finex should not be administered during pregnancy. Finex use is not advised orally during lactation. However, topical Finex amounts absorbed through the skin are very small and are unlikely to affect the child.

Drug Interactions: Tablets: In vitro studies show that terbinafine inhibits metabolism mediated by CYP2D6, a fact that may have clinical significance in drugs metabolised pro CYP2D6 (tricyclic antidepressants, beta blockers, selective inhibitors of serotonin reuptake inhibitors and monoamine oxidase type B). There have been some cases of menstrual irregularities in patients taking oral contraceptives, although the incidence of these disorders is low. Terbinafine caffeine clearance decreases by 20%. Concomitant use of terbinafine and alcohol can increase the risk of hepatotoxicity.