In medicine, centrally acting drugs are used to treat nervous disorders. The human central nervous system functions using two mechanisms:
- excitation,
- depression of nervous activity.
Phenobarbital is a drug with an inhibitory effect. How does this medicine work? After entering the human body, this drug is absorbed in the small intestine and enters the blood. In turn, the human circulatory system distributes the incoming drug to all organs and has an effect specifically on the nerve endings that receive exciting signals. "Phenobrabital" blocks excitatory signals.
The maximum effectiveness of Phenobarbital is observed at the level of the human medulla oblongata - the subcortical structures of the central nervous system. Due to the inhibition of the activity of the cerebral cortex, this drug has a pronounced sedative and hypnotic effect.
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Origin and history of the drug
Phenobarbital is a derivative of barbituric acid. It was synthesized by Adolf von Bayer in 1863. The drug became a huge discovery for its time, as it allowed psychiatrists to pacify a violent person who was in this state for a variety of reasons.
Barbital was officially introduced to the world in 1903, after which its improved versions began to appear, in particular phenobarbital.
Barbiturates skyrocketed in popularity as many people used it to relieve stress or insomnia. Later, problems and complications caused by the drug, as well as dependence on it, began to be identified. Cases of drug overdose often occurred, as some liked the state caused by barbiturates.
Effects of phenobarbital on the body
The drug affects the functioning of the cerebral cortex and also causes inhibited functioning of the thalamus, which leads to a sedative-hypnotic effect. The anticonvulsant effect is achieved by reducing neuronal excitability, which is caused by some psychotropic medications or a person’s mental disorder.
The sleep that occurs when using phenobarbital is significantly different from the healthy physiological sleep of an ordinary person. The REM sleep phase is shortened, and the third and fourth stages of slow-wave sleep are reduced. The sleep structure is completely restructured. The effect of the sleeping pill develops in less than an hour and lasts steadily for 8 hours, in some cases it can reach 12 hours. The effect decreases 2 weeks after the start of use.
In small doses, the medication provides a calming effect and, in combination with antispasmodic substances, helps with neurovegetative disorders.
Hypnotic doses of phenobarbital lead to a decrease in metabolic rate. They have a depressing effect on the main centers of thermoregulation, as a result of which a person’s temperature decreases.
Phenobarbital is absorbed almost immediately by the small intestine after oral administration. The half-life from the blood is approximately 80 hours; in children and newborns this figure may exceed 100 hours. The drug is evenly distributed throughout all human organs and also penetrates the placenta and breast milk. Phenobarbital is excreted from the body by the kidneys.
Contraindications
The drug is prohibited for use in the following situations:
- Hypersensitivity to all barbiturates;
- Severe anemia;
- Diseases associated with respiratory tract complications;
- Renal or hepatic insufficiency;
- Chronic alcoholism;
- Predisposition to drug or drug addiction;
- Pregnancy and breastfeeding;
- Diabetes;
- Suicidal tendencies or depression;
- Acute or constant pain.
The use of phenobarbital should not be combined with other depressants or alcohol. Combining substances can lead to an excessive increase in their effect and serious complications
Drug interactions
When used simultaneously with diazepam, amitriptyline, chlordiazepoxide and nialamide, the anticonvulsant effect of the drug increases, and with reserpine it decreases.
Valproate and phenytoin increase serum concentrations of phenobarbital.
When used together with salicylates and oral contraceptives, their effectiveness decreases.
Acetazolamide alkalinizes the urine, reducing the renal reabsorption of phenobarbital and weakening its effect.
The drug enhances the effect of neuroleptics, muscle relaxants, hypnotics and sedatives, narcotic analgesics and alcohol.
Phenobarbital reduces the blood concentration of glucocorticosteroids, estrogens, anticoagulants, doxycycline, griseofulvin and other drugs metabolized in the liver by oxidation.
When used simultaneously with sulfonamides and antibiotics, it reduces their antibacterial activity, and with griseofulvin, it reduces its antifungal effect.
Thiamine, atropine, dextrose, nicotinic acid, belladonna extract, psychostimulants and analgesics reduce the hypnotic effect of the drug.
How addiction occurs
An important feature of drugs in this group is that they can be addictive. People who have been using phenobarbital for some time may continue to use it even when there is no urgent need for it. They are attracted by the feeling of complete relaxation and calm.
Phenobarbital takes a relatively long time to be eliminated from the body, which means that regular use can lead to an overdose, even if taken in small doses. Active substances will accumulate in the body faster than the kidneys can remove them.
At the same time, the drug quickly becomes addictive. Since the effect of its action decreases after a few weeks, a person tries to increase the dose without even feeling its maximum amount in the body. This is the reason for frequent overdoses of phenobarbital.
Do you need treatment for phenobarbital? Find out the methods, timing and cost during a consultation
Overdose
In case of an overdose of the drug, symptoms of toxic poisoning may not appear immediately, but only several hours after taking Phenobarbital. With a single dose of 1000 mg of the drug, adults develop serious poisoning; with a dose of 2000–10,000 mg, death is usually observed. The therapeutic concentration of phenobarbital is 5–40 mcg/ml, lethal – 100–200 mcg/ml. Barbiturate poisoning should be distinguished from alcohol intoxication, various neurological disorders and bromide intoxication.
In acute intoxication with Phenobarbital, the following symptoms are observed: unusual eye movements, nystagmus, slurred speech, respiratory depression, ataxia, constriction of the pupils (changed to paralytic dilatation in case of severe poisoning), tachycardia, weak pulse, severe drowsiness, weakness, Cheyne-Stokes respiration, hypotension , cyanosis, clammy and cold skin, severe confusion, hemorrhages (when pressing on the skin), agitation, absent or weakened reflexes, dizziness, oliguria, coma, headache. In case of severe poisoning, pulmonary edema, apnea, vascular collapse, cardiac and respiratory arrest, and death are possible. In case of a life-threatening overdose of the drug, suppression of the electrical activity of the brain may be observed, which, however, should not be assessed as clinical death, since such an effect is reversible if damage associated with hypoxia has not yet developed. In case of overdose, complications such as arrhythmia, pneumonia, renal and heart failure are possible.
In case of acute overdose, treatment is aimed at accelerating the elimination of phenobarbital and maintaining the vital functions of the body. If the patient is conscious and the gag reflex persists, it is necessary to induce vomiting and administer activated charcoal. If induction of vomiting is contraindicated, gastric lavage is performed. To more quickly remove the already absorbed drug, saline laxatives, alkaline solutions are prescribed and forced diuresis is performed (if renal function is preserved). When carrying out the above activities, it is necessary to monitor the water balance and vital functions of the body.
As maintenance therapy, airway patency is ensured (possible use of oxygen and artificial ventilation), maintenance of normal body temperature and blood pressure, and, if necessary, infusion treatment and other anti-shock measures.
In case of severe phenobarbital poisoning, the development of shock or anuria, peritoneal dialysis or hemodialysis can be performed (during and after dialysis, it is necessary to monitor the concentration of the drug in the blood).
Signs of phenobarbital use
The effects of the drug always have a strong effect on a person, especially if the doses of use exceed medication standards and are regular. A person who frequently uses phenobarbital can be identified through the following symptoms:
- tired look, general lack of concentration and drowsiness;
- lack of mood and interest in the world around you;
- timidity and difficulty in making decisions;
- inappropriate and at times aggressive or angry reaction to loved ones;
- detached attention.
References
- Diagnosis and treatment of anxiety disorders of the neurotic level (anxiety-phobic, panic and generalized anxiety disorders). Clinical recommendations. Russian Society of Psychiatrists. M., 2015. - 50 p.
- Kukes, V., Sychev, D., Shikh, E. Studying the biotransformation of drugs - the way to increase the effectiveness and safety of pharmacotherapy. Doctor, 2007. - No. 1. - P. 68-75.
- Lepakhin, V.K., Pereverzev, A.P., Romanov, B.K. Comparative assessment of the number of reports of adverse drug reactions. Safety and risk of pharmacotherapy, 2015. - T. 1. - P. 30-36.
- Lepakhin, V.K., Romanov, B.K., Toropova, I.A. Analysis of reports of adverse drug reactions. Gazette of the Scientific Center for Expertise of Medical Products, 2012. - T. 1. - P. 22-25.
- Studenikin, V.M. The use of phenobarbital drugs in pediatric neurology and epileptology. Questions of practical pediatrics, 2014. - No. 9(6). — P. 75-79.
- Filimonova, A.A., Ziganshin, A.U., Ziganshina, A.E. Features of the metabolism of various drugs with the participation of cytochrome P-450 isoenzymes. Let's experiment. and clinical pharmacology, 2007. - T. 70. - No. 3. - P. 69-77.
Consequences of use: addiction, affects the psyche
Long-term use of the drug has a complex negative effect on the body.
Physical manifestations include the appearance of allergic reactions, rashes, dermatitis, swelling of the lips, eyelids and cheeks. Wounds do not heal well and often fester. Nausea, vomiting and constipation occur. The functioning of the cardiovascular system is disrupted. Long-term use leads to kidney problems. Pain appears in the back area.
It is important to understand that phenobarbital causes not only physical but also psychological dependence. Has a great influence on the human psyche.
The mental effects of phenobarbital are expressed in the form of difficulty breathing, dizziness and drowsiness. The peace of sleep disappears, nightmares appear, and the patient often wakes up at night. Thought processes are disrupted and it is difficult for a person to concentrate. Speech processes slow down.
The patient develops a constant feeling of fear and panic. A person is constantly worried and alarmed about something. He may hallucinate and not understand where he is.
Side effects
Adverse reactions are most often observed with long-term use of the drug. As a rule, this is inhibition of central nervous system activity, allergies , and a pronounced decrease in blood pressure. In addition, agranulocytosis , headache , calcium metabolism disorders, thrombocytopenia , vascular collapse, megaloblastic anemia , bradycardia , nausea, constipation , vomiting, folate deficiency, osteomalacia , impotence , hypocalcemia , impaired libido are possible.
Is it possible to quit on your own? Addiction Treatment
If you recognize a person addicted to barbiturates in time, you can get him out of this state. The main treatment is complete cessation of use of any drug from the barbituric group.
At the same time, abrupt cessation of use leads to withdrawal symptoms. The patient may experience convulsions, tremors, significant insomnia, fever, depression, vomiting and nausea. In some cases, abrupt withdrawal of phenobarbital can lead to coma.
For these reasons, drug addicts are treated in a hospital under the close supervision of competent doctors. Doses are reduced gradually over a long period of time. After two weeks, a noticeable decrease in the effects of withdrawal symptoms begins, and the patient returns to normal.
Full rehabilitation takes much longer, as the patient has to cope with depression and feelings of guilt, relearn how to enjoy life and establish social contacts.
Newborns
For newborns, this remedy can be used in case of hemolytic disease . It increases the detoxification function of the liver and reduces the bilirubin in the serum.
If mothers use the drug in the last trimester of pregnancy, for newborns this is fraught with the development of physical dependence on the drug and withdrawal syndrome , up to acute withdrawal syndrome, which manifests itself as epileptic seizures and increased excitability immediately after birth or during the first couple of weeks.
Use during childbirth in some cases causes respiratory depression in the infant, especially in premature infants.
Taking this drug as an anticonvulsant during pregnancy can cause bleeding in the baby in the first days after birth.
