Phenobarbital - instructions for use, dose, side effects, contraindications

Refers to the barbiturate group. Interacts with "barbiturate" site of benzodiazepine-gamma-aminobutyric acid-receptor complex, due to which increases sensitivity gamma-aminobutyric acid receptors to gamma-aminobutyric acid, leads to the opening of neuronal channels for chloride ions, which leads to an increase in their entry into the cell. Reduces the excitability of neurons in the epileptogenic focus and the spread of nerve impulses. It shows antagonism against a number of excitatory mediators (glutamate, etc.). Suppresses the sensory areas of the cerebral cortex, reduces motor activity, depresses the cerebral functions, including the respiratory center. Has no significant effect on the cardiovascular system. Reduces the tone of the smooth muscles of the gastrointestinal tract. In small doses, the intensity of metabolic processes decreases somewhat, which can be manifested by a slight hypothermia.

It has anticonvulsant, sedative (in small doses), hypnotic, antihyperbilirubinemic, myorelaxing and spasmolytic action. Being an inducer of microsomal oxidation enzymes in the liver, it increases its detoxification function, reduces the concentration bilirubin in the serum.

Pharmacokinetics:

When ingested slowly absorbed, completely. Maximum concentration in plasma blood is determined after 1-2 hours, the connection with plasma proteins is 50%, in newborns 30-40%. Metabolized in the liver, induces microsomal liver enzymes CYP3A4, CYP3A5, CYP3A7 (the rate of enzymatic reactions increases 10-12 times). Cumulated in the body. The half-life is 2-4 days. It is excreted by the kidneys in the form of glucuronide, about 25% - unchanged. Penetrates into breast milk and through the placental barrier.

Indications:

- Epilepsy (all types of seizures except absence seizures), epileptic seizures genesis;

- chorea;

- spastic paralysis;

- sleep disturbances, agitation, anxiety, fear.

Contraindications:

Hypersensitivity to any component of the formulation, expressed hepatic and / or renal insufficiency, drug dependency (including history), hyperkinesis, myasthenia gravis, severe anemia, porphyria, diabetes mellitus, hypofunction of the adrenal gland, hyperthyroidism, depressed, broncho-obstructive disease, active alcoholism, pregnancy, lactation.

This dosage is not applicable in children due to the inability to accurately dosing (for children, tablets containing 5 mg or 50 mg of pentobarbital).

Carefully:

Weakened patients (high risk of paradoxical arousal, depression and confusion, even with normal doses).

Dosing and Administration:

Inside.

For adults:

- sleep disorders: 100-200 mg for 0.5-1 h before bed;

- as a sedative drug: 50 mg 2-3 times a day;

- as an anticonvulsant: 50-100 mg 2 times a day.

With a decrease in liver function should be administered in smaller doses.

Side effects:

FROMabout the side of the nervous system: asthenia, dizziness, general weakness, ataxia, nystagmus, paradoxical reaction (especially in elderly and weakened patients - excitement), hallucinations, depression, nightmarish dreams, sleep disturbances, syncope.

Co hand musculoskeletal system: with prolonged use - violation of osteogenesis and development of rickets.

From the digestive system: nausea, vomiting, constipation, with prolonged use - a violation of the liver.

From the hematopoiesis: agranulocytosis, megaloblastic anemia, thrombocytopenia.

From the cardiovascular system: lowering of blood pressure.

Allergic reactions: skin rash, hives, swelling of the eyelids, face and lips, shortness of breath, rarely - exfoliative dermatitis, malignant exudative erythema (Stevens-Johnson syndrome).

Other: with prolonged use - drug dependence.

Overdose:

Symptoms: nystagmus, ataxia, dizziness, headache, blockage, blurred speech, severe weakness, decreased or loss of reflexes, pronounced drowsiness or agitation, increased or decreased body temperature, respiratory depression, dyspnea, lowering of blood pressure, narrowing of the pupils (alternating with paralytic enlargement), oliguria, tachi or bradycardia, cyanosis, confusion, cessation of brain electrical activity, pulmonary edema, coma, later pneumonia, arrhythmias, heart failure; when taking 2-10 g - a lethal outcome; with chronic toxicity - irritability, weakened ability to critical evaluation, sleep disorders, confusion.

Treatment: there is no specific antidote. Gastric lavage, reception of activated charcoal, conduct of detoxification therapy, symptomatic treatment, maintenance of vital body functions.

Interaction:

Phenytoin and valproate increase the content of phenobarbital in the blood serum.

Anticonvulsant effect of phenobarbital decreases with simultaneous reception with reserpine, increases with combination with amitriptyline, nialamide, diazepam, chlordiazepoxide.

Reduces the effectiveness of oral contraceptives and salicylates.

Reduces blood levels indirect anticoagulants, glucocorticosteroids, griseofulvin, doxycycline, estrogens and other drugs,

metabolized in the liver along the oxidation pathway (accelerates their destruction).

Strengthens the effect of alcohol, neuroleptics, narcotic analgesics, muscle relaxants sedatives and hypnotics.

Acetazolamide, alkalinizing urine, reduces the reabsorption of phenobarbital in the kidneys and weakens its effect.

The hypnotic effect of phenobarbital decreases with simultaneous reception with atropine, belladonna extract, dextrose, thiamine, nicotinic acid, analeptics and psychostimulating drugs.

Reduces the antibacterial activity of antibiotics and sulfonamides, antifungal action griseofulvin.

Special instructions:

Avoid prolonged use of the drug due to the possibility of its cumulation in the body and the development of addiction.

To avoid the development of the syndrome of "withdrawal" (headaches, "nightmarish" dreams,

drowsiness and / or insomnia), treatment should be discontinued gradually.

Effect on the ability to drive transp. cf. and fur:

During treatment, it is not recommended to drive the car, and also engage in activities that require speed of psychomotor reactions.

Form release / dosage:

Pills, 100 mg.

Packaging:

10 tablets per contour cell pack.

For 1 or 2 contour mesh packages together with instructions for medical use in a pack of cardboard.

Storage conditions:

In accordance with the rules for the storage of psychotropic substances on the List III "List of narcotic drugs, psychotropic substances and their precursors subject to control in the Russian Federation".

Store in a dark place at a temperature of no higher than 25 ° C.

Keep out of the reach of children.

Shelf life:

5 years.

Do not use after the expiration date.

Terms of leave from pharmacies:On prescription

Registration number:LSR-002303/07

Date of registration:17.08.2007

The owner of the registration certificate:Anzhero-Sudzhensky Chemical-Pharmaceutical Plant, LLC Anzhero-Sudzhensky Chemical-Pharmaceutical Plant, LLC

Manufacturer: & nbsp

Anzhero-Sudzhensky Chemical-Pharmaceutical Plant, LLC Russia

Information update date: & nbsp20.09.2015

Illustrated instructions

Instructions

Phenobarbital (Phenobarbital)