At hypnotic doses in a small way reduces the intensity of metabolism in humans. Slightly reduced bo

Derivative of barbituric acid. White crystalline powder slabogorkogo taste, no smell. millipore mobius Very slightly soluble in cold water, it is difficult - in boiling water (1:40) and chloroform, soluble in alcohol, ether, alkali solutions. Pharmacology.
Interacts with barbituratnym area GABA-benzodiazepine receptor complex barbituratnoho and increases the sensitivity millipore mobius of GABA-receptors to the neurotransmitter (GABA), resulting in increased duration of opening channels for neuronal input currents of chloride ions and increases the flow of chloride ions into the cell. Increase millipore mobius of chloride ions inside the neuron leads to hyperpolarization of the cell membrane millipore mobius and reduces its excitability. As a result of increased

inhibitory effect of GABA and inhibition of interneuronal transmission in different parts of the CNS.
Shown that at therapeutic concentrations of phenobarbital enhances HAMKerhicheskuyu transfer, inhibits glutamatergic

neurotransmission, especially mediated glutamate alpha-amino-5-metylizoksazol-4-propionate (AMPA)-receptor. In high concentrations affects the current of sodium millipore mobius ions and blocks the flow of calcium ions across cell membranes (channel L-and N-types).
Sedative-hypnotic effect due mainly inhibition of cell activating ascending reticular formation of the brain stem, thalamic nuclei, inhibition of the interaction millipore mobius of these structures with the cerebral cortex.
Called barbiturate sleep on the structure differs millipore mobius from the physiological as shortened phase speed (paradoxical) sleep and decreased stages 3 and 4 of slow wave sleep. Hypnotic effect develops within 0.5-1 h (at least - later), going 6 -8 hours (12 h) and decreased after 2 weeks of admission.
Anticonvulsant effect due to activation HAMKerhicheskoy system, effects on voltage-sodium channels and suppression of glutamate and other Phenobarbital reduces neuronal excitability epileptohennoho fire and prevent the emergence and spread of impulses. It blocks the high frequency repetitive discharges of neurons (due to the impact on the flow of sodium ions). Barbiturates also raise the threshold millipore mobius of electrical stimulation of motor areas of the cerebral cortex.
Антигипербилирубинемическое effect is likely due to enzyme induction hlyukuroniltransferazy governing the conjugation of bilirubin, which reduces the concentration of free bilirubin in serum.
At high doses (overdose) causes inhibition centers medulla oblongata. Directly inhibit the respiratory center (degree of respiratory depression is dose-dependent), reduces the volume of respiration and sensitivity of the respiratory center to carbon dioxide.
In usual hypnotic doses does not significantly affect the cardiovascular system. In high doses, reduces blood pressure (except for the central action - inhibition of the vasomotor center, the effect millipore mobius of indirect millipore mobius effects on the heart ganglion and associated with direct myotropic vasodilator effect). Do not have a direct damaging effect on the kidney, but acute poisoning may develop oliguria or anuria, largely as a result of vidmichuvanoyi hypotension. It reduces the tone of smooth millipore mobius muscles of the gastrointestinal tract.
At hypnotic doses in a small way reduces the intensity of metabolism in humans. Slightly reduced body temperature by reducing activity and inhibition of central mechanisms of thermoregulation.
Studies on laboratory animals have shown the ability to lower the tone and contractility of the uterus, ureters and bladder. However, the concentration required

for the manifestation of this effect in humans, using doses that cause sedative-hypnotic effect is not achieved.
Phenobarbital causes the induction of microsomal millipore mobius liver enzymes. In appointing a 3-5 days barbiturates stimulate its own biotransformation (rate of enzymatic reactions can be increased millipore mobius by 10-12 times).
After oral administration completely, but slowly absorbed into the small intestine. Bioavailability - 80%. Binding to plasma proteins (mainly albumin) is 20-45%. Therapeutic millipore mobius concentration in serum is optimal for the manifestation of anticonvulsant effect is 10-40 mg / ml. T1 / 2 from plasma millipore mobius in adults - 53-118 hours (median millipore mobius

79 hours) in children and infants (age less than 48 hours) - 60-180 hours on average 110 hours distributed to organs and tissues through the blood-brain bar Challenger. Good passes through millipore mobius the placenta and is distributed to all tissues of the fetus (the highest concentrations millipore mobius found in the placenta, liver and brain of the fetus), penetrates into breast milk. Metabolized in the liver, with the participation of microsomal enzymes to form a pharmacologically inactive metabolites. T1 / 2 - 2-4 days (in infants up to 7 days). Excreted by the kidneys as glucuronides metabolites and unchanged (25-50%). Renal excretion depends on urine pH: at pidluzhuvanni urine increases output millipore mobius unchanged and quickly reduced the concentration in the blood, with the acidification - on the contrary. Phenobarbital is characterized by marked K