Isoniazid

General characteristics. Structure:

International and chemical names: isoniazid; hydrazide of isonicotinic acid; main physical and chemical properties: tablets on 100 mg of a round form, white or almost white color, with a flat surface, with a facet; tablets on 200 mg of a round form, white or almost white color, with a flat surface, with slanted edges (with a facet) and risky; structure: 1 tablet contains an isoniazid 100 mg or 200 mg; excipients: povidone, starch corn, кросповидон, calcium stearate.

Pharmacological properties:

Pharmacodynamics. The isoniazid has high bacteriostatic activity in relation to tuberculosis mycobacteria. The isoniazid affects actively breeding mycobacteria of tuberculosis and is less effective in relation to the bacteria which are in rest. The mechanism of its action is connected with suppression of synthesis of mikoliyevy acids with a long chain which are components of a cellular cover of mycobacteria. Drug detains growth of mycobacteria at the person in concentration of 0,03 mkg/ml. On other widespread causative agents of infectious diseases drug has no the expressed chemotherapeutic effect.

Pharmacokinetics. It is well soaked up from the digestive channel, easily gets through a blood-brain barrier and it is found in various fabrics and liquids of an organism. After intake the maximum concentration in blood is observed in 1–4 h, tuberculostatic concentration in blood after reception in a single dose is observed by 6-24 h.
It is removed generally by kidneys. By quantity of the active Isoniazid allocated with urine in relation to the accepted dose patients belong to "bystry" and "slow" inactivators. To the first category carry patients at whom with urine about 10% of the Isoniazid a day are allocated, to the second – more than 10% a day.
Isoniazid elimination half-life in a blood plasma at bystry acetylation – 0,5–1,6 h, at slow – 2–4 h, at a renal failure – 2–5 h, at a heavy renal failure – 5–7 h.

Indications to use:

Treatment of tuberculosis of all forms and localizations.

Route of administration and doses:

Doses establish individually depending on character and a form of a disease, sensitivity to drug. Inside to adults and children appoint in a daily dose 5–15 mg to 1 kg of body weight, in 2–3 receptions after food. Daily and course doses are established individually depending on character and a form of a disease, degree of an inactivation and sensitivity. Treatment – long.

Features of use:

As a result of treatment only the Isoniazid forms resistant strains of mycobacteria therefore it is applied in a combination with other antituberculous remedies. It is necessary to select correctly a dose according to ability to inactivate the Isoniazid. Before purpose of the Isoniazid it is reasonable to determine the speed of its inactivation by the content of active agent in blood and in urine. To patients at whom the bystry inactivation is observed the Isoniazid is appointed in higher doses. For reduction of side effects along with the Isoniazid appoint a pyridoxine a hydrochloride (inside or intramusculary) either glutaminic acid, or Thiamini chloridum or Thiamini bromidum (intramusculary), the ATP sodium salt.
There are no messages that drug can negatively influence the types of activity requiring special attention and bystry mental and motor reactions.

Side effects:

The headache, dizziness, nausea, vomiting, pains in heart, skin allergic reactions are possible; euphoria, deterioration in a dream, it is rare – development of psychosis, emergence of peripheral neuritis with emergence of an atrophy of muscles and paralysis of extremities; hepatitis. Very seldom – a gynecomastia at men, menorrhagias at women.
By-effects pass at reduction of a dose or a temporary break in administration of drug.

Interaction with other medicines:

Absorption of the Isoniazid in the digestive channel decreases when using antiacid means. Appoint in a combination with other antitubercular drugs. At multi-infection it is necessary to accept other antibacterial drugs at the same time: antibiotics of a broad spectrum of activity, streptocides, ftorkhinolona.
The isoniazid oppresses biotransformation of carbamazepine and dipheninum therefore at the combined use their concentration in a blood plasma increases and toxic action amplifies.
Toxicity of the Isoniazid increases at a concomitant use of MAO inhibitors.

Contraindications:

Epilepsy, tendency to convulsive attacks; earlier postponed poliomyelitis, an abnormal liver function and kidneys. It is not necessary to appoint the Isoniazid in doses over 10 mg/kg at pregnancy, a pulmonary heart ІІІ degrees, an idiopathic hypertensia ІІ– ІІІ a stage, an ischemic heart disease, widespread atherosclerosis, diseases of a nervous system, bronchial asthma, psoriasis, eczema in an aggravation phase, a myxedema.

Overdose:

High doses of drug promote development of an ataxy, twitching of muscles, paresthesias, a stupor and toxic encephalopathy. Toxic doses (40 mg/kg and more) cause a heavy metabolic acidosis, a hyperglycemia and a glucosuria, spasms and a coma.
Treatment: a gastric lavage, purpose of absorbent carbon for 2–3 h after reception. Carry out the supporting treatment, intravenously enter a pyridoxine, repeating if necessary introduction on 5 g each 5–30 minutes before the termination of spasms or recovery of consciousness; at spasms also appoint diazepam.

Storage conditions:

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

Period of validity - 6 years.

Issue conditions:

According to the recipe

Packaging:

The tablets containing 100 mg of the Isoniazid: on 100 tablets in a glass jar and a pack; on 100 tablets in a glass jar; on 1000 tablets in a container plastic.
The tablets containing 200 mg of the Isoniazid: on 100 tablets, in a glass jar and a pack; on 100 tablets in a glass jar; on 500 and 1000 tablets in a glass jar or a container plastic; on 10 tablets in a blister strip packaging, on 5 packagings in a pack.