Valproic acid (sodium valproate) refers to a relatively new group of anticonvulsants that differ from previously used antiepileptic drugs both in chemical structure and in principle of action.
Description of the substance
This chemical was synthesized in 1882 as an analogue of valerianic acid by Dr. W. Barton. It consists of 2 cut groups. For many decades, valproic acid was used only in laboratory conditions as an inert solvent of various organic compounds. Its anticonvulsant properties were discovered by a fluke.
Valproic acid is clear and liquid at room temperature. However, it is able to interact with a base, for example sodium or magnesium hydroxide, with the formation of a valproate salt, which is a solid substance. This substance, in fact, is 2-propylvaleric acid and its sodium salt. Unlike other antiepileptic drugs, it is a nitrogen-free compound. The mechanism of action of this acid and its salts is associated with a specific effect on the metabolism of gamma-aminobutyric acid, which is an inhibitor of the transferase enzyme.
Preparations, which include valproic acid, reduce the stimulating and convulsive reaction of the motor zones of the brain. This is due to the fact that this substance increases the content of gamma-aminobutyric acid in the structures of the nervous system. Valproic acid, reviews of which indicate its effectiveness in the treatment of anticonvulsant conditions, belongs to the group of derivatives of fatty acids.
Characterization of valproic acid, its analogues
Valproic acid, the instruction to which describes its complex effect on humans, is available under various names. The most famous drugs that contain this substance are Depakine, Convulex, Convulsofin, Orfilin, Deprakin, Epilim, Everiden, Encorat, Apilepsin, Valparin XP "," Dipromal ". In the finished dosage forms, it may be in the form of an acid or its sodium salt, called sodium valproate. The activity of the drug from this does not decrease. Valproic acid, the analogues of which are listed above, is taken orally immediately after a meal. All preparations containing it are rapidly absorbed. After 2 hours, this acid appears in the blood plasma. It penetrates well through tissue barriers. Residual traces of this substance are determined in the cerebrospinal fluid and in many other internal environments of the body. It is also found in amniotic fluid (amniotic fluid) in pregnant women.
Operating principle
How does valproic acid work? The instruction for this drug does not give an exact answer to the question of what is the mechanism of its therapeutic effect. This is due to the fact that specialists have not yet fully studied its effect on the change in the properties of sodium channels. At the same time, valproic acid is included in the list of medicines that are vital and important for people.
Human action
Not only with epilepsy is valproic acid used. Instructions for use of this drug indicate that it has not only an anticonvulsant effect. It improves the mood, as well as the mental state of a person. Experts say that this acid has a tranquilizing component. Unlike other drugs of this kind, it reduces the state of fear without exerting a myoleraxant or sedative effect. This is due to its effect on postsynaptic membranes. At the same time, the processes of transmission of nerve impulses are suppressed.
In small forms of epilepsy, they are most often limited to taking one valproic acid or its analogues. In more severe cases, this drug is combined with other antiepileptic drugs.
Valproic acid for epilepsy
This drug is used for various forms of epilepsy. In this case, its reception is based on the scheme established by the doctor. Valproic acid, the instruction for use of which indicates its effectiveness in various forms of this disease, is used in individual cases in different doses. Also, it is often prescribed for focal seizures.
Drug use
Valproic acid, the instructions for which require the appointment of a drug by the attending physician and strict adherence to the treatment regimen, is used in such cases:
• prevention of various complications of epilepsy;
• convulsive conditions that occur with some diseases of the central nervous system;
• the presence of a nervous tick;
• manic-depressive psychosis, not amenable to treatment with drugs containing lithium;
• convulsive conditions that occur in childhood.
Reception of valproic acid and preparations containing it should be carried out exclusively under the supervision of the attending physician. Only after carrying out all the necessary studies and assessing the condition of the patient, the specialist will be able to choose a safe and effective dosage of this drug.
Release form
Valproic acid, the release form of which is different, is packaged by different manufacturers in the following form:
• Enteric coated tablets. They contain 150, 200, 300, 500 mg of valproic acid (sodium valproate).
• Capsules of 150, 300 mg.
• A medicine (syrup) containing 50 or 300 ml of a medicinal substance in 1 ml.
Compatibility with other drugs
Valproic acid is able to enhance the action of other anticonvulsants and antieleptic drugs, antipsychotics, antipsychotics, antidepressants, and alcohol. You should not drink alcohol while taking this medicine. Valproic acid, analogues of this drug, salicylic acid and anticoagulants have an inhibitory effect on platelet aggregation. If it enters the intestines, this drug is rapidly absorbed into the bloodstream. At the same time, the use of valproic acid simultaneously with any food slightly reduces its effectiveness.
Side effects
This drug sometimes causes side effects in the form of nausea, vomiting, decreased appetite, severity and pain in the stomach, diarrhea. To eliminate these conditions, enveloping or antispasmodic agents are used. Valproic acid can cause general depression and fatigue, so it is rarely prescribed to people engaged in intense physical and mental work. Taking this medication sometimes leads to disorders of the nervous system, which manifest as tremor of the extremities, bifurcation of images and visual disturbances, drowsiness, headache, dizziness, psychomotor agitation, depression and apathy.
In some cases, taking this drug leads to the following consequences: decrease and increase in body weight, the appearance of allergic reactions, temporary hair loss, menstrual irregularities, and changes in the hemogram. Rare, but very serious side effects of taking this drug are impaired functioning of the liver or pancreas, a decrease in blood coagulation. Hepatotoxic effect is most likely when taking this drug simultaneously with clonazepam, phenobarbital.
When using valproic acid, it must be remembered that in patients with diabetes, it can distort the result of urine analysis, increasing the content of ketone bodies in it. To prevent various complications during treatment , the blood levels of bilirubin, liver enzymes, and platelet counts are regularly determined.
Contraindications
Valproic acid, which is sold over the counter in a pharmacy, has serious contraindications. These include:
• impaired functioning of the pancreas and liver;
• porphyria;
• hemorrhagic diathesis;
• individual intolerance;
• first trimester of pregnancy;
• feeding period (the drug passes into mother’s milk).
In the II and III trimester of pregnancy, this drug is prescribed in smaller doses and only for serious indications, since it crosses the placenta and can affect the unborn baby.
When taking valproic acid, it is necessary to carefully monitor the functioning of the liver, to control blood coagulation and platelet aggregation. During the treatment with this drug, women who have sex should use the most reliable contraceptive methods to prevent pregnancy.
Application patterns
Preparations containing this acid are taken according to different schemes. Optimal doses are selected individually. The patient’s condition, weight and age affect the choice of dosage regimen. Most often, at the beginning of the course, adults and children, whose weight exceeds 25 kg, are prescribed 10-15 mg / kg per day. In the future, each week, the dose of the drug is increased by 5-10 mg / kg, bringing it to a maximum of 30 mg / kg. The daily dose for children is 20-50 mg / kg. When switching to valproic acid treatment, the administration of other anticonvulsants is gradually reduced. The maximum dose of valproic acid should not be higher than 50 mg / kg per day.
There are various forms of release of this drug. Intravenous administration involves the intake of 400-800 mg of sodium valproate per day. Throughout the course of therapy, it is necessary to determine the level of this drug in the blood. According to analyzes, adjustments can be made to the treatment regimen.
Approximate application schemes:
• Children under 3 years: in the first week they drink 150 mg 1 p. per day, in the second - 150 mg 2 r. per day, and in the third - 150 mg 3 p. in a day.
• Children 3 to 10 years old: in the first week they take 450 mg, in the second - 600 mg, in the third - 900 mg per day. According to another scheme, take 300, 450, 600, 900 mg per day, respectively, at 1, 2, 3 and 4 weeks.
• After 10 years: in the first week they drink 600 mg, in the second - 900, in the third - 1200 mg per day. According to another scheme, take 300, 600, 900, 1200 mg per day, respectively, at 1, 2, 3 and 4 weeks.
For patients who have previously taken other anticonvulsants, valproic acid is prescribed in reduced doses. At the same time, the amount of other funds is reduced. The maintenance dose for adults is 900-1200 mg. Valproic acid, tablets and capsules of which are prescribed only after 10 years, is taken in 2-4 doses. For children, syrup or medicine with this drug is most often prescribed.
"Depakine" (valproic acid)
Various drugs with this acid are on sale, but Depakin is one of the most popular. In pharmacies there are several types of this drug: "Chrono", "300 Enteric", "Chrononosphere granules" and others. All of them differ slightly in the content of the active substance and the form of release. "Depakine" is prescribed as an anticonvulsant and mood stabilizing drug. He has proven himself in the treatment of epilepsy, bipolar disorder, tonic-clonic seizures, myoclonus, depression, migraine headaches. It is also used to treat neuropathic pain. Recently, this drug is being investigated as a medicine for some types of cancer and HIV infection.
Long-acting valproic acid
Among the preparations of valproic acid, Depakin and its analogues are in high demand. This is due to the fact that it has a prolonged effect. The use of this drug entails a decrease in the incidence of convulsive seizures. It also reduces their severity and facilitates the course. Depakine reduces the likelihood of more severe complications.
Valproic acid metabolism is carried out by liver cells. When taking the usual substance, the half-life is about 6-8 hours. Modern drugs allow you to maintain a therapeutic concentration of the active substance in the body up to 16 hours. The rate of excretion of valproic acid depends largely on the functioning of the liver. Valproic acid, reviews of which are mostly positive, affects each patient in their own way. This is due to the fact that each organism is unique and can perceive this substance with some deviations from the norm.