Terbinafin, cream 1% 15 g

Terbinafine is an antifungal agent. It has a broad spectrum of action against fungi that cause skin, hair and nail diseases, including:

• dermatophytes such as Trichophyton (e.g., T. rubrum, T. mentagrophytes, T. verrucosum, T. tonsurans, T. violaceum), Microsporum (e.g., M. canis), Epidermophyton floccosum;
• degenerative fungi of the genus Candida (e.g., C. albicans) and Pityrosporum.

In low concentrations terbinafine has fungicidal effect against dermatophytes, molds and some dimorphic fungi. Activity against yeast fungi, depending on their species, may be fungicidal or fungistatic.

The mechanism of action is associated with specific suppression of the early stage of sterol biosynthesis in the fungal cell. This leads to a deficit of ergosterol and to intracellular accumulation of squalene, which causes cell death of the fungus. The action of terbinafine is performed by inhibiting the enzyme squaleneepoxidase in the cell membrane of the fungus. This enzyme does not belong to the cytochrome P450 system. Terbinafine has no significant effect on the metabolism of hormones or other drugs.

Pharmacokinetics

When terbinafine is administered orally, concentrations of the drug are created in the skin, hair and nails to provide fungicidal action.

After a single oral dose of 250 mg of terbinafine, its maximum plasma concentration is reached after 2 hours and is 0.97 µg/ml. The half-absorption period is 0.8 hours, and the half-distribution period is 4.6 hours. Although the bioavailability of terbinafine is moderately altered by food, but not to such an extent that correction of the drug dose is required.

Terbinafine is largely bound to plasma proteins (99%). It quickly penetrates through the dermal layer of the skin and concentrates in the lipophilic stratum corneum. Terbinafine also penetrates into the sebaceous gland secretion, resulting in high concentrations in hair follicles, hair and sebaceous gland-rich skin. Terbinafine has also been shown to penetrate the nail plates in the first few weeks of therapy.

Terbinafine is metabolized rapidly and to a significant extent with the participation of at least seven cytochrome P450 isoenzymes, with CYP2C9, CYP1A2, CYP3A4, CYP2C8 and CYP2C19 isoenzymes playing the major role. As a result of biotransformation of terbinafine metabolites are formed, which have no antifungal activity and are excreted mainly with the urine. The terminal elimination half-life is 17 hours. There is no evidence of cumulation of the drug in the body. No changes of terbinafine plasma equilibrium concentration depending on age have been found, but in patients with impaired renal or hepatic function the drug excretion rate may be delayed, resulting in higher terbinafine blood concentrations.

Less than 5% of the dose is absorbed when the spray or cream is applied topically, so the systemic effects of the drug are minimal.

Indications

Active ingredient

Composition

1 g of the cream contains:

The active substances:

terbinafine hydrochloride 10 mg;

Excipients:

benzyl alcohol,

polysorbate 60 (tween 60),

sorbitan monostearate,

cetyl alcohol,

isopropyl myristate,

cetyl palmitate,

sodium hydroxide,

purified water.

How to take, the dosage

Terbinafine can be applied to the skin once or twice a day. Before application, the affected areas should be cleaned and dried. Apply a thin layer on the affected skin and adjacent areas and rub gently. In infections accompanied with diaper rash (under the breasts, between the fingers, between the buttocks, in the groin area), the places where the cream is applied can be covered with gauze, especially at night.

The average duration of treatment:

A reduction in the severity of clinical manifestations is usually noted in the first days of treatment. If treatment is irregular or if it is discontinued prematurely, there is a risk of recurrence of the infection. If there are no signs of improvement after two weeks of treatment, verification of the diagnosis should be made.

The use of the drug in the elderly:
There is no reason to believe that the dosage of the drug needs to be changed for the elderly or that they experience side effects different from those in younger patients.

Children:
There is limited experience with use in children.

Interaction

There are no known drug interactions for terbinafine ointment/cream.

Contraindications

Hypersensitivity, expressed hepatic and renal insufficiency, blood diseases, tumors, metabolic diseases, vascular pathology of the extremities, pregnancy, lactation, children (under 12 years).

Side effects

Perception of heaviness and pain in the epigastric region, impaired taste, decreased appetite, nausea, diarrhea, cholestasis, neutropenia, thrombocytopenia, skin allergic reactions; burning sensation, skin redness and itching in the application area of the cream.

Overdose

Symptoms:

Headache, dizziness, nausea, vomiting, epigastric pain, rapid urination, rash.

Treatment:

Maintenance of the drug (gastric lavage, activated charcoal administration); if necessary – symptomatic supportive therapy.

Pregnancy use

In experimental studies terbinafine had no teratogenic properties.

The use of the drug in pregnancy is possible in cases where the estimated benefit to the mother exceeds the possible risk to the fetus. Terbinafine is excreted with the breast milk.

If it is necessary to use the drug during lactation, the question of stopping breastfeeding should be addressed.

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