Terbinafine

Pharmacological properties

A synthetic antifungal drug from the group of allylamines with a wide spectrum of antifungal action. in low concentrations it has fungicidal activity against dermatophytes, mold and some dimorphic fibs. the effect on yeast fibs can be fungicidal or fungistatic depending on the type of fibs. the drug inhibits the biosynthesis of sterols in the fungal cell, which leads to a deficiency of ergosterol, the accumulation of squalene inside the cell and its death. exifin does not affect the metabolism of hormones or other drugs. exifin is effective against pathogens of dermatomycosis (trichophyton spp., microsporum canis and epidermophyton floccosum), yeast-like Phoebe of the genus candida. unlike topical administration, its oral administration is ineffective in pytiriasis versicolor.

When administered orally, the drug accumulates in the skin and nails in a fungicidal concentration. 2 hours after taking 250 mg of terbinafine, its maximum plasma concentration is reached, which is 0.97 μg / ml; simultaneous ingestion of food does not affect its bioavailability. Terbinafine almost completely binds to plasma proteins (99%). It quickly diffuses through the dermis and accumulates in the lipophilic stratum corneum of the epidermis. It is secreted with the secret of the sebaceous glands. A high concentration is created in the hair follicles, hair, oily skin and in the nail plate. Biotransformation in the liver leads to the formation of metabolites that do not have antifungal activity and are excreted mainly in the urine. The half-life is 17 hours. It does not cumulate in the body. No changes in pharmacokinetics depending on the age of the patient were noted, however, in patients with impaired renal or hepatic function, the rate of excretion of the drug from the body can be reduced, resulting in a higher concentration of terbinafine in the blood plasma.

Indications

Gel: fungal infections of the skin caused by dermatophytes, such as trichophyton (t. Rubrum, t. Mentagrophytes, t. Verrucosum, t. Violaceum), microsporum canis and epidermophyton floccosum, for example, interdigital epidermophytosis of the feet (athletes foot), inguinal dermatophytosis ("Jockey itch"), dermatophytosis of the body ("ringworm"). lichen caused by pityrosporum orbiculare (malassezia furfur).

Tablets: dermatomycoses (epidermophytosis of the skin and nail plates, rubromycosis, trichophytosis, microsporia), candidiasis of the skin and mucous membranes, mycotic lesions of the ENT organs, genitourinary system.

Application

Gel: applied to the skin once a day. Before applying the drug, it is necessary to thoroughly clean and dry the affected areas of the skin. the gel is applied in a thin layer to the affected skin and adjacent areas and rubbed lightly. with diaper rash in the skin folds (under the mammary glands, between the fingers, between the buttocks, in the groin area), places with gel can be covered with gauze, especially at night.

Duration and frequency of application of the gel.

Dermatophytosis of the body, inguinal dermatophytosis: 1 time per day for 1 week.

Dermatophytosis of the feet (interdigital): 1 time per day for 1 week.

Usually, the positive dynamics of the clinical picture of the disease is noted after a few days. Irregular use of the drug or premature discontinuation of treatment may lead to relapse.

For elderly patients, dose adjustment is not necessary.

Due to insufficient clinical experience, the drug should not be used in children.

Tablets: for adults, exifin is administered orally at 250 mg once a day; children with a body weight of 20 kg — 62.2 mg / day, 20–40 kg — 125 mg / day, 40 kg — 250 mg / day.

There is no data on the use of the drug in children under the age of 2 years (body weight 12 kg).

The duration of treatment depends on the severity of the infection and the type of pathogen. So, with the interdigital form of mycoses and lesions of the soles, the duration of treatment is 2-6 weeks, with herpes zoster, skin candidiasis - 24 weeks.The complete disappearance of the symptoms of the disease occurs after a few weeks. With onychomycosis, the duration of treatment in most cases is from 6 weeks to 3 months. With slow nail growth, a longer course of treatment may be needed.

If after 2 weeks there are no signs of improvement, microbiological verification of the diagnosis is necessary.

Contraindications

Hypersensitivity to the drug, the age of 6 years, the period of pregnancy and lactation.

Side effects

There may be a feeling of fullness of the stomach, anorexia, nausea, abdominal pain, diarrhea, skin rash. when allergic reactions occur, the drug is canceled.

special instructions

Patients with severe renal and / or liver failure should be prescribed the drug in lower doses. when prescribing the drug to elderly patients, the possibility of having impaired liver or kidney function should be considered.

In experimental studies, the embryotoxic effect of terbinafine was not detected, however, clinical experience with the drug in pregnant women is insufficient. It is not recommended to use the drug during pregnancy, especially in the first trimester, in the absence of absolute indications for its use. Exifin passes into breast milk, so you should stop breast-feeding during treatment.

Interactions

It has a slight effect on the clearance of drugs that are metabolized with the participation of the cytochrome p450 system (cyclosporine, tobutamide, oral contraceptives). elimination of exifin can be accelerated with the simultaneous use of inducers of microsomal liver enzymes (rifampicin) and slowed with the simultaneous administration of cytochrome p450 inhibitors (cimetidine). with simultaneous use with such drugs, dose adjustment of exifin is necessary.

Overdose

Cases of overdose are not described. it can be assumed that an acute overdose of the drug will be accompanied primarily by disorders of the digestive tract (nausea, vomiting). should rinse the stomach, prescribe activated charcoal, according to indications - symptomatic treatment.

Storage conditions

In a dry, dark place at temperatures up to 25 ° C.