Isoniazid

General characteristics. Structure:

Active agent: isoniazid of 300 mg; 200 mg; 100 mg.

Pharmacological properties:

Antituberculous remedy of the I row. Has bactericidal effect. The isoniazid is active in the relation out of - and intracellular Mycobacterium tuberculosis, first of all concerning actively sharing. The exact mechanism of its action is unknown. It is supposed that it is connected with suppression of synthesis of the mikoliyevy acids which are a part of a cell wall of mycobacteria.

Pharmacokinetics. After intake it is quickly absorbed from a GIT. At reception with food absorption and bioavailability decrease. It is widely distributed in all fabrics and liquids of an organism. Linkng with proteins of plasma very low (0-10%). It is metabolized in a liver. A small amount - with a stake is removed with urine.

Indications to use:

Treatment of all forms of active tuberculosis, including tubercular meningitis (as a part of a combination therapy). Prevention of tuberculosis at the persons which are in close contact with TB patients; at persons with positive skin reaction (more than 5 mm) to tuberculine and the radiological data indicating not progressing tuberculosis; at children 4 years with positive reaction to tuberculine (more than 10 mm) and the increased risk of dissimination are younger.

Route of administration and doses:

The dose is established individually, depending on character and a form of a disease.

Inside to adults and teenagers - on 300 mg of 1 time/days or on 15 mg/kg/days 2-3 times a week (as it is defined by the scheme of therapy), to children - 10-20 mg/kg of 1 time/days or on 20-40 mg/kg 2-3 times a week (as it is defined by the scheme of therapy).
To adults in oil and teenagers enter 5 mg/kg of 1 time/days or on 15 mg/kg 2-3 time/week, to children - on 10-20 mg/kg of 1 time/days or on 20-40 mg/kg 2-3 times a week.
Duration of treatment is established individually.
Vnutrikavernozno enter 10-15 mg/kg in a daily dose. At inhalations - 5-10 mg/kg/days in 1-2 receptions.
The maximum daily dose for adults at intake and in introduction makes 300 mg.

Features of use:

It is not recommended to apply an isoniazid in a dose more than 10 mg/kg at severe forms of cardiopulmonary insufficiency and/or arterial hypertension, an ischemic heart disease, widespread atherosclerosis, diseases of a nervous system, bronchial asthma, psoriasis, eczema in an aggravation phase, a myxedema.

In order to avoid bystry development of stability of Mycobacterium tuberculosis the isoniazid is applied in a combination with other antituberculous remedies.

After an injection the patient needs to observe a bed rest during 1-1.5 h.

For reduction of side effects along with an isoniazid appoint a pyridoxine (inside or in oil), or glutaminic acid (inside), or thiamin (in oil).

It is necessary to consider that the isoniazid is metabolized in a liver by acetylation to inactive metabolites. Extent of acetylation is determined by genetic factors. Due to unequal extent of metabolism before use of an isoniazid it is reasonable to determine the speed of its inactivation by the content of active agent in blood and urine. At patients at whom the bystry inactivation is observed the isoniazid is applied in higher doses.

Side effects:

- From TsNS and a peripheral nervous system: headache, dizziness; seldom - psychosis, euphoria, sleep disorders, peripheral neuritis.
- From the alimentary system: nausea, vomiting, medicinal hepatitis.
- From cardiovascular system: pains in heart.
- From endocrine system: very seldom - a gynecomastia at men, menorrhagias at women.
- Allergic reactions: skin rash, itch.

Interaction with other medicines:

At simultaneous use with rifampicin the risk of development of a hepatotoxic action increases (especially at patients with abnormal liver functions).

At simultaneous use with paracetamol the risk of development of a hepatotoxic action since the isoniazid induces P450 cytochrome that leads to increase in maintenance of toxic metabolites of paracetamol increases.

At simultaneous use of an isoniazid with carbamazepine or Phenytoinum metabolism of the last is suppressed that leads to increase in their concentration in a blood plasma and to strengthening of toxic action.

Contraindications:

Epilepsy, convulsive attacks and poliomyelitis in the anamnesis, an abnormal liver function and/or kidneys, atherosclerosis.

Use at pregnancy and feeding by a breast
Use of an isoniazid at pregnancy and in the period of a lactation (breastfeeding) is possible.
The isoniazid gets through a placental barrier, is allocated with breast milk.

Use at abnormal liver functions
It is contraindicated at an abnormal liver function.

Use at renal failures
It is contraindicated at a renal failure.

Storage conditions:

In the dry, protected from light place, at a temperature not above 25 °C.
To store in the place, unavailable to children.

Issue conditions:

According to the recipe

Packaging:

Tablets of 300 mg; 200 mg; 100 mg: 20, 50 or 100 pieces.