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Active ingredients
Terbinafin
Release form
Pills
Composition
1 tab. terbinafine hydrochloride 281.25 mg, which corresponds to a terbinafine content of 250 mg. Excipients: colloidal silicon dioxide - 3.
Pharmacological effect
Terbinafine belongs to the group of allylamines, is an antifungal agent with a broad spectrum of action. By inhibiting the enzyme squalene epoxidase, it interferes with the biosynthesis of the sterol cell membrane of the fungus, which leads to a deficiency of ergosterol and intracellular cumulation of squalene and the death of fungal cells. The effect of CYP4503A4 isoenzymes and, therefore, on the metabolism of hormones and drugs, the metabolism of which is associated with these isoenzymes, does not affect. In low concentrations, it has a fungicidal effect on dermatophytes (Trichophyton rubrum, T. mentagrophytes, T. tonsurans, T. verrucosum, T. violaceum, Microsporum canis, Epidermophyton floccosum), among mold fungi - on Candida parapsilosis and some dimorphic fungi. It shows fungistatic activity against mold fungus Candida albicans. When ingestion accumulates in the skin, nails and hair in an amount that has a fungicidal effect. The minimum inhibitory concentration for Trichophyton rubrum is 0.001-0.06 mcg / ml.
Pharmacokinetics
Cmax of terbinafine in plasma (0.97 mcg / ml) after oral administration of 250 mg is determined after 1-2 hours. Eating does not affect the bioavailability, which is 80%; communication with plasma proteins 99%. It is quickly distributed in tissues, in layers of skin and nails. It is secreted with the secretion of the sebaceous glands, is found in large concentrations in hair follicles and hair and skin areas with a large number of sebaceous glands, accumulates in the stratum corneum (the concentration increases 10 times on the 2nd day after taking 250 mg, on the 12th day - 70 times), nails (the rate of diffusion exceeds the growth rate of the nail) in concentrations that provide fungicidal action. Already in the first weeks of treatment is found in the nail plate. Metabolized in the liver, the largest number of inactive metabolites excreted by the kidneys (71%), 22% - through the intestines. Penetrates into breast milk. T1 / 2 is 17 hours. There is no data confirming the accumulation of the drug. Age does not affect pharmacokinetics; in violation of the functions of the liver or kidneys, excretion worsens with subsequent increase in the concentration of the drug in the blood.
Indications
- onychomycosis caused by dermatophytes - skin mycoses caused by trichophytes (T. rubrum, T. mentagrophytes, T. verrucosum, T. violaceum, etc.), microspores (M. canis, M.Gypseum, etc.) and Epidermophyton floccosum - severe, common dermatomycoses of smooth skin of the body, legs, feet, requiring systemic treatment, and candida of the skin - mikozy scalp (trichophytosis, microsporia).
Contraindications
- children's age up to 2 years (due to the lack of necessary clinical experience) - breastfeeding period - severe liver disease - hypersensitivity to the drug. With care: during pregnancy, in patients with renal insufficiency, in alcoholism, inhibition of bone marrow hematopoiesis, tumors, metabolic diseases, occlusive vascular diseases of the extremities.
Use during pregnancy and lactation
The drug is prescribed with caution during pregnancy (only in the case when the intended benefit to the mother outweighs the potential risk to the fetus). Terbinafine passes into breast milk. In appointing the drug during lactation should decide on the abolition of breastfeeding.
Dosage and administration
The duration of treatment depends on the clinical picture of the disease and its severity. Adults: usually 1 tablet of 250 mg orally daily, after meals. Onychomycosis: the duration of therapy is about 6-12 weeks. With the defeat of the nails, in some cases, especially with slow growth of the nails, a longer treatment may be required. With the defeat of the nails of the brushes, usually 6 weeks of the course is enough, the nails of the feet, especially the thumb - 12 weeks. The duration of therapy depends on the age of the patient, the presence of concomitant diseases and nail conditions at the beginning of treatment. In most cases, clinical recovery occurs within a few months after a negative mycological study, which is associated with the growth rate of a healthy nail. Mycoses of smooth skin: with interdigital, plantar or socks-type localization of the infection, the duration of treatment is 2-6 weeks, with mycosis of the body or lower legs - 2-4 weeks, with candidiasis of the skin - 2-4 weeks, with candidosis of the scalp - 4 weeks, in the case of M. canis infection - more than 4 weeks. Children: for mycosis of the scalp is prescribed in doses that adults. With a body weight of 12 to 20 kg, 1/2 tablet 125 mg 1 time / day (62.5 mg); with a body weight of 20-40 kg - 125 mg 1 time / day, with a body weight of more than 40 kg - 250 mg / day. Patients with impaired renal function, Terbisil is prescribed with caution; for renal failure, 125 mg 1 time per day. Taking terbinafine during pregnancy is not recommended due to the lack of clinical trials.Administration of Terbisil in pregnancy is possible only when the intended benefit to the mother outweighs the potential risk to the fetus.
Side effects
Terbisil is usually well tolerated. Side effects are usually mild and short-lived. On the part of the digestive system: sometimes - feeling of full stomach, nausea, mild abdominal pain, diarrhea, loss of appetite; rarely - a violation of taste perception, incl. losing it, recovering a few weeks after stopping treatment; extremely seldom - severe violations of the liver (cholestasis, jaundice, hepatitis, however, the causal relationship with taking Terbisil is not established (in such cases, treatment with Terbisil should be stopped). From the side of the central nervous system: slight headache, dizziness. seldom - neutropenia, agranulocytosis, thrombocytopenia (a causal relationship with terbinafine is not established.) From the immune system: sometimes - myalgia, arthralgia, skin rash, exanthema, urticaria, edema; rarely - multiforme Erit ema; very rarely - severe skin reactions (toxic epidermal necrolysis, Stevens-Johnson syndrome); very rarely - severe anaphylactoid reactions. Terbismil treatment should be stopped in severe skin and anaphylactic reactions. Others: enhanced hair loss (no causal relationship has been established).
Overdose
Symptoms: nausea, vomiting, pain in the epigastric region and in the lower abdomen, dizziness. Treatment: gastric lavage is performed followed by the appointment of activated carbon and / or symptomatic supportive therapy.
Interaction with other drugs
Virtually no effect on clearance of drugs metabolized in the presence of cytochrome P450 (for example, cyclosporine, terfenadine, tolbutamide, triazoles, oral contraceptives). Inhibits CYP2D6 isoenzyme and interferes with the metabolism of drugs such as tricyclic antidepressants and selective serotonin uptake blockers, 1-blockers, MAO-B blockers; prescribing them requires caution, especially in the case of a narrow therapeutic range. CYP450 enzyme inducer drugs (for example, rifampicin) can accelerate the excretion of terbinafine from the body, and CYP450 inhibitor drugs (for example, cimetidine) can slow the excretion of terbinafine. With the simultaneous use of these drugs may require a dose adjustment of terbinafine. Reduces caffeine clearance by 20%.Ethanol and other hepatotoxic drugs increase the risk of a hepatotoxic effect.
special instructions
Unlike Terbisil intended for topical use, the pills are not effective against the multi-colored lichen, caused by the pathogen Malassezia furfur. Systemic use in onychomycosis is justified only in the case of a total lesion of most nails, the presence of pronounced subungual hyperkeratosis, the ineffectiveness of the previous local therapy. Treatment should be preceded by an analysis of indicators of liver function, which should be regularly and frequently repeated during treatment. The drug should be canceled when confirming the hepatic etiology of the symptoms of liver dysfunction that appeared during treatment. In severe impaired renal function (KK less than 50 ml / min or blood creatinine> 300 μmol / l), the dose of terbinafine should be halved. Irregular use of terbinafine or pre-treatment termination of treatment leads to a relapse of the disease. Terbinafine accumulates in the nail plate and in the skin, often the clinical effect appears only after a few weeks. When treating with terbinafine, you should follow the rules of hygiene to prevent re-infection through underwear and shoes. In the process of treatment (after 3 weeks) and at the end of it, it is necessary to produce antifungal treatment of shoes, socks and stockings. Impact on the ability to drive and work mechanisms: There is no data indicating the effect of terbinafine on the ability to drive and to perform work requiring increased concentration of attention.