Valproic acid (sodium valproate) belongs to a relatively new group of anticonvulsants that differ from previously used antiepileptic drugs both in chemical structure and in the principle of action.
Description of the substance
This chemical was synthesized in 1882 as an analog of valeric acid by Dr. W. Barton. It consists of 2 propyl groups. For many decades, valproic acid was used only in the laboratory as an inert solvent for various organic compounds. Its anticonvulsant properties were discovered by sheer luck.
Valproic acid is clear and liquid at room temperature. However, it is able to interact with a base, such as sodium or magnesium hydroxide, to form a s alt of valproate, which is a solid substance. This substance, in fact, is 2-propylvaleric acid and its sodium s alt. Unlike other antiepileptic drugs, it is a nitrogen-free compound. The mechanism of action of this acid and itss alts is associated with a specific effect on the metabolism of gamma-aminobutyric acid, which is an inhibitor of the transferase enzyme.
Drugs containing valproic acid reduce the excitatory and convulsive response of the motor areas 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 fatty acid derivatives.
Characteristics of valproic acid, its analogues
Valproic acid, the instructions for which describe its complex effects on humans, is available under various names. The most famous drugs that include this substance are Depakin, Konvuleks, Konvulsofin, Orfilin, Deprakin, Epilim, Everiden, Enkorat, Apilepsin, Valparin XP", "Dipromal". In finished dosage forms, it can be in the form of an acid or its sodium s alt, called sodium valproate. The activity of the drug does not decrease from this. Valproic acid, the analogues of which are listed above, is taken orally immediately after meals. 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 manyother internal environments of the body. It is also found in the amniotic fluid (amniotic fluid) in pregnant women.
Operation principle
How does valproic acid work? The instructions for this drug do not give an exact answer to the question of what is the mechanism of its therapeutic effect. This is due to the fact that experts have not yet fully studied its effect on changing 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.
Action on a person
Valproic acid is not only used for epilepsy. Instructions for use of this drug indicates 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 having a myoleraxant or sedative effect. This is due to its action on postsynaptic membranes. At the same time, the processes of transmission of nerve impulses are suppressed.
In small forms of epilepsy, most often they are 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 in various forms of epilepsy. In this case, its reception is based on the established doctorscheme. Valproic acid, the instructions for use of which indicate its effectiveness in various forms of this disease, is used in some cases in different doses. It is also often prescribed for focal seizures.
Using the drug
Valproic acid, the instructions for which require the prescription of the drug by the attending physician and strict adherence to the therapy regimen, is used in such cases:
• prevention of various complications of epilepsy;
• convulsive conditions that occur with certain diseases of the central nervous system;
• Presence of a nervous tic;
• manic-depressive disorder not responding to lithium medications;
• convulsive conditions that occur in childhood.
Valproic acid and preparations containing it should only be taken under the supervision of the attending physician. Only after carrying out all the necessary studies and assessing the patient's condition, the specialist will be able to choose a safe and effective dosage of this drug.
Issue form
Valproic acid, the release form of which is different, is packaged by different manufacturers in the following form:
• Tablets, coated, soluble in the intestine. They contain 150, 200, 300, 500 mg of valproic acid (sodium valproate).
• Capsules 150, 300 mg.
• A medicine (syrup) containing 50 or 300 ml of medicinal substance in 1 ml.
Compatibility with othersdrugs
Valproic acid can enhance the effect of other anticonvulsants and antieleptics, neuroleptics, antipsychotics, antidepressants, and alcohol. Do not drink alcohol while taking this medicine. Valproic acid, analogues of this drug, salicylic acid and anticoagulants have an inhibitory effect on platelet aggregation (combination). When ingested, this drug is rapidly absorbed into the bloodstream. At the same time, the use of valproic acid simultaneously with any food somewhat reduces its effectiveness.
Side effects
This drug sometimes causes side effects in the form of nausea, vomiting, loss of appetite, heaviness 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 strenuous physical and mental work. Taking this medicine sometimes leads to nervous system disorders, which manifest as tremors of the limbs, double images and visual disturbances, drowsiness, headache, dizziness, psychomotor agitation, depression and apathy.
In some cases, taking this drug leads to the following consequences: a decrease and increase in body weight, the appearance of allergic reactions, temporary hair loss, menstrual irregularities, changes in the hemogram. Rare but very serious side effectsThis remedy is considered a violation of the functioning of the liver or pancreas, a decrease in blood clotting. 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 a urine test, 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, whose preparations are sold in pharmacies without a prescription, has serious contraindications. These include:
• violations of the pancreas and liver;
• porphyria;
• hemorrhagic diathesis;
• idiosyncrasy;
• first trimester of pregnancy;
• lactation period (drug passes into mother's milk).
During the second and third trimester of pregnancy, this drug is prescribed in smaller doses and only for serious indications, since it crosses the placenta and may affect the unborn child.
When taking valproic acid, it is necessary to carefully monitor the functioning of the liver, control blood clotting and platelet aggregation. While on therapy with this drug, women who are sexually active should usethe most reliable methods of contraception to prevent pregnancy.
Application patterns
Preparations containing this acid are taken according to different schemes. Optimal doses are selected individually. The choice of regimen depends on the condition of the patient, his weight and age. 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, every 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 treatment with valproic acid, the intake of other anticonvulsants is gradually reduced. The maximum dose of valproic acid should not exceed 50 mg/kg per day.
There are different forms of this drug. Intravenous administration involves taking 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 the analysis, adjustments may be made to the treatment regimen.
Indicative Application Charts:
• Children under 3 years old: in the first week they drink 150 mg 1 r. a day, the second - 150 mg, 2 r. per day, and in the third - 150 mg 3 r. per day.
• Children 3-10 years old: 450 mg in the first week, 600 mg in the second week, and 900 mg in the third week. According to another scheme, they 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, they take 300, 600, 900, 1200 mg per dayrespectively 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 number 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, a syrup or mixture with this drug is most often prescribed.
"Depakine" (valproic acid)
There are various preparations with this acid on sale, but one of the most popular is Depakine. In pharmacies there are several types of this drug: "Chrono", "300 Enteric", "Chronosphere granules" and others. All of them differ somewhat in the content of the active substance and the form of release. "Depakine" is prescribed as an anticonvulsant and mood-stabilizing drug. It has proven itself in the treatment of epilepsy, bipolar disorders, tonic-clonic seizures, myoclonus, depression, migraine headaches. It is also used to treat neuropathic pain. Recently, this drug is being investigated as a drug for certain types of cancer and HIV infection.
Valproic acid long-acting
Among valproic acid preparations, Depakine and its analogues are in high demand. This is due to the fact that it has a prolonged effect. Use of this drugleads to a reduction in the frequency of seizures. It also reduces their severity and facilitates the course. "Depakine" reduces the likelihood of more severe complications.
Valproic acid is metabolized by liver cells. When taking a regular substance, the half-life is about 6-8 hours. Modern preparations allow maintaining the therapeutic concentration of the active substance in the body for 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 its own way. This is due to the fact that each organism is unique and may perceive this substance with some deviations from the norm.
