Terbizil, tablets 250 mg, 14 pcs.

Pharmacodynamics

Antifungal drug. Terbinafine is an allylamino derivative. It has a broad spectrum of antifungal action.

In therapeutic concentrations terbinafine has fungicidal action against: dermatophytes – Trichophyton, Microsporum, Epidermophyton; yeast-like fungi: Genus Candida: Candida albicans; some dimorphic fungi. Pityrosporum orbiculare: Malassezia furfur.

The activity against yeast fungi, depending on their species, may be fungicidal or fungistatic.

Terbinafine specifically inhibits the early stage of sterol biosynthesis in the fungus cell by inhibiting the enzyme squalene epoxidase in the fungus cell membrane. This leads to ergosterol deficiency and intracellular accumulation of squalene, which causes cell death of the fungus. Squalene epoxidase is not part of the cytochrome P450 system, so terbinafine has no effect on the metabolism of hormones or other drugs.

Pharmacokinetics

Intake

After a single oral dose of terbinafine 250 mg, C max in plasma is reached after 2 hours and is 0.97 µg/ml. Food intake has no effect on the bioavailability of terbinafine.

In topical application of the cream less than 5% of the dose is absorbed.

Distribution

The binding to plasma proteins is 99%. When applied topically, it quickly penetrates through the dermal layer of the skin and accumulates in the lipophilic stratum corneum. Terbinafine also penetrates into the sebaceous gland secretion, resulting in high concentrations in hair follicles and nails. During the first few weeks after initiation of oral administration, terbinafine accumulates in the skin and nail plates in concentrations that provide fungicidal action.

Terbinafine is excreted with breast milk.

Metabolism and excretion

Terbinafine is metabolized in the liver to form inactive metabolites. Most of the inactive metabolites (71%) are excreted in the urine, a smaller portion (22%) in the feces.

The T 1/2 is 11 to 17 h. There is no evidence of cumulation of the drug in the body.

Pharmacokinetics in special clinical cases

In patients with impaired hepatic or renal function the elimination rate of terbinafine from the body may be reduced.

Indications

Active ingredient

Composition

Active ingredient:

terbinafine 250 mg.

Auxiliary substances:

Microcrystalline cellulose (PH 101 and PH 102),

Hypromellose, carboxymethylcellulose type “A”,

silicone colloidal anhydrous,

magnesium stearate.

How to take, the dosage

In onychomycosis

The duration of effective treatment is 6-12 weeks and is determined by the growth rate of healthy nails. In some cases (with slow nail growth), the course of treatment may be longer. The duration of therapy may also depend on other factors: the patient’s age, the presence of concomitant disease, and the condition of the nails at the beginning of treatment. The optimal clinical effect is observed several months after mycological cure and discontinuation of therapy. This is determined by the period of time required for the growth of a healthy nail.

The recommended duration of treatment

In dermatomycosis of the feet (interfinger, plantar or sock type) is 2-6 weeks.

In dermatomycosis of the trunk, shins – 2-4 weeks.

For mycoses of the scalp, 4 weeks (but may be longer if infected with Microsporum canis).

Interaction

Terbizil has a slight ability to slow down or increase clearance of drugs that are metabolized by cytochrome P 450 isoenzymes (cyclosporine, tolbutamide, oral contraceptives).

The excretion of terbinafine may be accelerated by drugs that cause induction of microsomal liver enzymes (rifampicin).

Drugs that inhibit cytochrome P 450 isoenzymes (cimetidine) slow down excretion of terbinafine. If it is necessary to use these drugs simultaneously Terbizil dose adjustment may be required.

Special Instructions

Use in liver dysfunction

Patients with significant liver dysfunction should have the drug dose reduced by half

Patients with renal dysfunction

Patients with significant renal dysfunction

Patients with significant renal dysfunction (CKG less than 50 ml/min or a serum creatinine concentration greater than 300 µmol/L) the drug dose should be reduced by half.

It should be noted that if during Terbizil treatment a patient has liver dysfunction (weakness, nausea of unknown etiology, lack of appetite, jaundice, darkened urine or pale stools) the drug should be discontinued.

Hepatic transaminase levels should be monitored during treatment.

In treatment with Terbisil, general rules of hygiene should be followed to prevent the possibility of reinfection (through underwear or shoes).

Please note that irregular use or premature withdrawal of the drug leads to a recurrence of the disease.

Contraindications

Side effects

Gastrointestinal system: often – feeling of full stomach, loss of appetite, dyspepsia, nausea, mild abdominal pain, diarrhea; rarely – disorders or loss of taste sensation (recovery occurs within several weeks after discontinuation of treatment); in individual cases – cholestasis, jaundice, hepatitis (although the causal relationship of these disorders with Terbizil administration is not established, in case of hepatobiliary dysfunction the drug treatment should be stopped).

With the hematopoietic system: in some cases – neutropenia, thrombocytopenia.

Allergic reactions: often – rash, urticaria: in single cases – Stevens-Johnson syndrome, toxic epidermal necrolysis (in case of development of progressive skin rash Terbizil treatment should be stopped).

Overdose

Symptoms: nausea, vomiting, lower abdominal pain.

Treatment: gastric lavage followed by activated charcoal. If necessary, symptomatic therapy is carried out.

Pregnancy use

Due to the lack of data on the safety of the use of terbinafine in pregnant women, Terbizil in this category of patients is used only in cases where the expected positive effect exceeds the potential risk.

Terbinafine is excreted with breast milk, so the use of the drug during lactation is contraindicated.

Similarities