Phenobarbital

Chemical name

5-Этил-5-фенил-2,4,6(1Н,3Н,5��)-пиримидинтрион

Gross

C12-H12-N2-O3

Characteristics

Derived barbiturova acid. The white crystalline powder slabogorki taste, odourless. Very little is soluble in cold water, it is difficult, in cold water (1:40), and chloroform, soluble in alcohol, ether, alkaline solutions.

Of drugs

The drugs-protivosudorozhnoe, nursing, sedative. Interfaces with barbituratnam site ГАМК_А-бензодиазепин-��арбитуратного IL1 complex and increases sensitivity to Gamk-retseptorov mediatoru (GABA), thus increasing the length of time disclosure neironalnah channels for incoming currents chlorine ions and increasing the flow of chlorine ions in the cell. Increasing the chlorine ions inside neirona entails giperpoliarizatia cell membranes and lowers her anxiety. As a result, the braking effect GABA and oppression mezhneironna transfer in the various divisions Zns.pokazano that therapeutic concentrations of phenobarbital increases Gamkergicescuu transfer hampered glutamatergicescuu neirotransmissiu, particularly indirect glutamatnami альфа-амино-5-метилизо ксазол-4-пропионат (AMPA) -retseptorami. In high concentrations affect the current sodium ions and blocks current calcium ions across cell membranes (channels and L-N-tipov). Barbiturates are selective dampening effect on the central nervous system. They suppress sensory cortex of the brain reduces motor activity and cause drowsiness, and sedative effect and сон.Седативно-снотвор ное the increase was primarily due to the oppression activity of cells upstream activator retikuliarna formations barrel brain nuclei cheeks, application of these structures overbark lead Mozga.vzvanny barbituratami sleep on the structure differs from the physical, as phase shift quickly (paradoxical) sleep and decreasing stage 3 and 4 sleep slow. Hypnotic effect develops over 0.5-1 hrs (more later), has 6-8 hours (up to 12 hours) and is reduced after two weeks приема.Противосудоро��ное Effects of activated Gamkergicaka system, the impact on potencial-zawisimae sodium channels, as well as the suppression of glutamate activity, etc. Phenobarbital reduces neuronal excitability epileptogennogo fire and prevent the emergence and spread of impulses. It locks up high neuronal level (due to the impact on current sodium ions). Barbiturates also raise the threshold Electrical motor cortex of the parent мозга.Антигипербилир��бинемическое is the result of enzyme induction glukuroniltransferzy governing kongugatia cium, which leads to a decrease in the free cium in Savorotke.may a little analgesia, but it is possible and better response to pain Stimul.v low doses has a calming effect and, in conjunction with other means (spazmoliticaskie, sossoudorasshirate) efficient at neirovegetativeh Rasstrojstwah.pri high doses (with overdose) is the oppression of oblong brain. Just imagine breathing Centre (the depressed respiration depends on the dose), reduces the amount of respiratory and skin sensitivity to the carbon Gazu.v gipnoticakih conventional doses have no significant impact on the cardiovascular system. In high doses lowers AD (with the exception of the central-oppression sossoudodwigatelnogo centre, the effect consequential impact on the heart, ganglia, as well as linked to the direct miotroponam sossoudorasshiratm act). There is a direct action damaging to the kidneys, but acute poisoning may develop oligurii or anurii, largely as a result of observed hypotension. Lowers tone smooth muscles JKT.V gipnoticakih doses marginally reduces the intensity of metabolism in humans. Slightly lower body temperature by reducing activity and oppression of the central Termoregulyation.v studies on laboratory animals show the lower tone and the ability Oxytocics uterus, and mochetocnikov bladder. However, the concentrations required for the exercise of this effect in humans, using doses of the sedativo-snotvornoe not достигаются.Фенобарб��тал induction is mikrosomaionah enzymes peche

Indications

Epilepsy, trochaic, spasticeski paralysis patients peripheral arteries, eclampsia, causing insomnia, Hemolytic disease of newborns.

Restrictions on the use of

Depression and / or suicidal tendencies, bronchial asthma in history, the liver and / or kidney giperkinez, Ray (possibly increased symptoms, as barbiturates squeezed tiroksin associated with the plasma protein), hypothyreosis napochechnikov (possibly weakening the system of exogenous and endogenous hydrocortisone under the influence of barbiturates) severe or persistent pain (there can be a paradoxical institution, or may conceal important symptoms), pregnancy (II and III trimester), children's age.

Pregnancy and lactation

Contraindicated in the first trimester of pregnancy (possible teratogenic effects). Application during pregnancy is possible only by strict conditions, with no other Sredstv.rezultata controlled retrospective studies have shown that the admission of barbiturates pregnant women is the cause of the increased frequency anomalies Ploda.u newborns whose mothers took phenobarbital in the third trimester of pregnancy, to the development of physical dependence and withdrawal syndrome (there are reports of severe withdrawal syndrome, in proavlevchegosa pripadkah seizures and excessive excitability immediately after birth or within 14 days of birth, prolonged exposure to vnutriutrobnomu barbituratami). It is known that that the use of phenobarbital as a means protivosudorozhnogo during pregnancy result in a disruption of blood clotting (of vitamin C) in newborns, which may cause bleeding in the neonatal period (usually on the first day after birth). Application during childbirth can cause respiratory depression in the newborn, especially prematurely (due to underdeveloped liver). At the time of treatment should stop breast-feeding (penetrates into breast milk and may cause central nervous system oppression baby).

Contraindications

Гиперчувствительност ь (incl. other barbiturates), or manifestirutaya latentnaya porphyria in history (perhaps increasing symptoms by induction of enzymes responsible for the synthesis of porphyrin), respiratory diseases accompanied by shortness of breath or obstruction respiratory tract, liver and / or kidney failure, male, alcoholism, drug abuse or dependence, including in the disease, pregnancy (especially I trimester), breast-feeding.

Side-Effects

From the nervous system and sensory organs : drowsiness, lethargy, oppression respiratory centre, dizziness, headache, nervousness, anxiety, hallucinations, ataxy, nightmares, giperkinesia (children), the process of thinking, paradoxical reaction (unusual action, insomnia), especially in children, the elderly and handicapped patients, the effect aftereffect (fatigue, a sense of razbitosti, weakness, reducing emotional reactions and concentration). From the circulatory system and blood (blood, gemostaz) : agranulozitos, thrombocytopenia, and gipotenzia megaloblastnaya anaemia (with the long-term use), aetiology, Stroke Kollaps.so part of the intestine : nausea / vomiting, Zapor.allergicakie reactions : skin rash or urticaria, local swelling (especially century, cheeks or lips), exfoliativei dermatitis (syndrome Stevens-Johnson, It'sa toxic nekroliz); possible death Ishod.prochie : with long-term use, the liver lesion (jeltushnosti skler or skin), the lack of folate, gipocalziemia, osteomalacia, the deadly, addictive Impotenzia.vazavaet (found in about 2 weeks of treatment), drug dependency (mental and physical), the syndrome and "impact" (see "Precautions").

Specific guidance

Currently, phenobarbital, as a means to eliminate practically applied.

Patient interaction

Do metabolism PP, биотрансформирующихс я in the liver (due to the activation of enzymes mikrosomaionah oxidation), and reduces the effects : proximity anticoagulants, including racumin, atenokumarola, fenindiona etc. (reduces levels of anticoagulants in the blood, while the appointment of a periodic monitoring protrombinovogo time to correct doses of anticoagulants), Corticosteroids, drugs naperstanki, chloramphenicol, metronidazole, doxycycline (reduces T_1/2 doxycycline, the effect may persist for two weeks after receiving barbiturata), tricyclic antidepressants, and estrogen, salicilatov, paracetamol, etc. Phenobarbital reduces induction grizeofulvina and level it Krovi.effect barbiturates on metabolism protivosudorozhnykh funds derived gidantoina (including phenytoin), unpredictable (perhaps less or greater fenitoina concentration in the blood, a monitoring plasma concentrations). Valproeva acid, sodium valproat raise the level of phenobarbital in blood. Phenobarbital reduces concentration in plasma carbamazepina, Klonazepama.pri simultaneously with the application of other means, oppressive CNS (including sedatives, hypnotics, some antihistamines, anxiolitiki), and alcohol can OVD additive effect. MAO inhibitors prolong the effect of phenobarbital (probably because of its oppression metabolism).

Overdosing

Cimptoma toxic poisoning may not appear for a few hours after taking phenobarbital. Toxic dose varies considerably. Admission into 1 g of a serious poisoning in adults, reception 2-10 g usually cause death. Therapy level of phenobarbital in human blood is 5-40 µ g / ml, death, 100-200 µ g / J Barbituratami poisoning should be differentiated drunkenness, intoxication bromidami with various neurological расстройствами.Симпт��мы acute intoxication : movement, unusual eye movements, ataxy expressed weakness and drowsiness, and severe sputannosti consciousness smazannaya speech initiation, dizziness, headache, respiratory depression, breathing Chan-stocksa weakening or absence of reflexes, narrowing inhibition (with serious poisoning smenauscheesa paralysis expansion), oliguria, tachycardia, gipotenzia, hypothermia, zianoz, weak pulse, cold and sticky skin, gemorragii (at the points tipped), Koma.pri serious poisoning can develop healthy lungs, Stroke collapse of the declining vitality peripheral receptacles patients, cause respiratory and heart; possible death Ishod.pri life threatening overdose may suppress the electrical activity of the brain (EEG can be "flat"), which is not to be seen as a clinical death, as This effect is completely reversible, if not developed lesions resulting from гипоксией.Передозиро��ка in the outcome of such complications as pneumonia, irregular, long heart failure, renal �едостаточность.Лечен ие acute overdose : accelerating out of phenobarbital and maintaining vital Funksii.dla reduce removals (if not phenobarbital vsosalsa completely from the stomach), vomiting induction (if the patient is conscious and not lost emetic reflex), followed by the appointment of activated carbon, and there is a need to take measures to prevent aspiration Findings masses. If induction vomiting contraindicated, should be washed Jeludka.dla accelerate breeding vsosavchegosa drug appoint salt laxatives, a big diurez (if you saved the kidney), using alkaline solutions (for oschelacivania urine). Would monitor vital functions and Water баланса.Поддерживающ��е Mera.neobhodimo road maintenance respiratory tract, if necessary IVL and the use of oxygen; analeptikov use is not recommended (with serious poisoning can deteriorate); maintenance of normal AD (with hypotension application sossoudossoujiwath funds), and body temperature; if necessary infuzionnaya therapy or other protivosokove measures; steps should be taken to prevent gipostaticescoy pneumonia (including the physiotherapy in the thorax), faeces, aspiration and other complications; with suspected pneumonia-appointment of antibiotics; should avoid overloading or liquid waste, especially if there is a violation of the cardiovascular Sistema.pri heavy poisoning, the anurii or shock to the peritoneal dialysis or hemodialysis (during and after dialysis to monitor phenobarbital concentration in the blood). Symptoms of chronic toxicity : constant irritability, a reduction in the ability to make a critical self-assessment, insomnia, drowsiness, fatigue, weakness, imbalance, it sputannaya, dizziness expressed sputannosti consciousness. There are hallucinations, agitation convulsions, disruption of blood, cardiovascular system and Pocek.lechenie chronic toxicity : the gradual dose reduction (to avoid going development syndrome) to the complete abolition of the drug, treatment of symptoms and psychotherapy.

Precautions

When skin complications phenobarbital should be abolished. Reactions гиперчувствительност и more likely to be found when the history of asthma Urticaria, angioneuroticeski oedema and Dr.sleduet bear in mind that the elderly and handicapped patients in normal doses may express agitation or depression sputannosti consciousness. Children barbiturates could cause unusual arousal, irritability, Giperaguosti.s caution to appoint depression (possibly deteriorating, especially in patients older). The risk of dependence increases in the use of high doses and with the increase in the length of admission, as well as in patients with drug and alcohol problems in the disorder. Permanent use of barbiturates in doses three or four times higher than therapeutic leads to the development of physical dependence to 75% Patientov.otmenu should be undertaken gradually by lowering doses for a long time to reduce the risk of depression and the "impact." Withdrawal syndrome can develop within 12 hours after taking the last dose, and usually manifests itself in the sequence (small symptoms) : anxiety, muscle apnoea, shaking hands, progressive weakness, dizziness, visual impairment, nausea, vomiting, insomnia, ortostatical gipotenzia (dizziness, the unconscious). In severe cases, can more symptoms (convulsions, deliri) arising out for 16 hours and continued to 5 days after the dramatic lifting. Manifestation of the syndrome has been declining for a period of approximately 15 days. The risk of deliria and convulsing with possible fatal above Quick aside after prolonged use for people with drug dependency. The sudden end to the admission of epilepsy can cause nervous or suspects Status.pri phenobarbital application for the treatment of epilepsy to monitor its level in the blood. In long-term care needs periodic determination of the concentration of iron in the blood, control picture peripheral blood, liver and Pocek.pri need to use barbiturates childbirth to take delivery in readiness Oborudovania.v surgical treatment period not use alcoholic Napitkov.ne should be applied in conjunction with the drivers of vehicles and people which requires quick mental and physical reactions, as well as linked to the high concentration of attention.

Dosing and Administration

Inside. The dispensing establish a case-by-case basis, depending on the evidence, of course, portable, age, etc. Treatment to start with the lowest effective dose for a particular type of pathology. In patients with impaired liver and / or kidney problems, the elderly and handicapped patients treatment should start with smaller Doz.v a bush-grown 0.1-0.2 g for 0.5-1 hours before sleep; As a sedative and spazmoliticski means-0,01-0,03-0,05 g 2-3 times a day (usually in combination with spazmolitikami, vazodilatatorami, etc.); with epilepsy : adult-0.05-0.1 g twice a day with a gradual increase in dose to the clinical Effecta.maximalnaya single dose for adults - 0.2 g, the maximum daily 0.5 G.dozu for children picked individually depending on the age, body mass index child.

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