Anticonvulsant drugs - drugs that can prevent or to stop attacks seizures of different origin. Currently, the term anti-convulsants usually apply in respect of the drugs used to prevent various manifestations of epilepsy (antiepileptic drugs).
To anticonvulsant tools include primidone (see), phenytoin (see), trimethadione (see), fenacon (see), beclamide (see), phenobarbital (see), benzonal (see).
Anti-convulsants (except phenobarbital) selectively inhibit spasmodic reaction, not providing General depressive effect on the Central nervous system and causing a hypnotic effect.
Depending on the clinical manifestations of epilepsy assign different anti-convulsants. To prevent large seizures apply phenobarbital, benzonal, primidone, phenytoin, beclamide. Trimethadione effective for preventing small seizures. Often for the treatment of epilepsy rationally utilize a combination of anticonvulsants (concurrently or sequentially).
Treatment anticonvulsant drugs are long, for many months. Therefore, there are various side effects associated with taking anticonvulsants (see articles about individual protivosudorozhnykh funds). Treatment with phenytoin, geksamidinom, hlorakona, trimetinom is not suitable for violations of the liver, kidneys and blood-forming organs. Trimethadione also contraindicated in diseases of the optic nerve. Anticonvulsant drugs are used to prevent epileptic status; for his edema use geksenal, magnesium sulfate (parenteral) or chloral hydrate, barbitala-sodium enemas.
Anti-convulsants (synonym anticonvulsive funds) - medicinal substance that can prevent the development of seizures of different etiology. Strictly speaking, the term anticonvulsant drugs should be indicated only substances used for treatment of different forms of epilepsy, therefore it is more correct to call this group of drugs "antiepileptic drugs".
Warning seizures or eliminate already developed seizure can be achieved by other neurotropic substances sedative-type drugs, barbiturates, chloral hydrate), but P.F. effect is achieved without concomitant depression of the Central nervous system, i.e. the action of P.F. election. Chemically, modern P.F. presents barbiturates, derived gidantoina, giocarecasinoitaliano, b-chlorpropamide, oxazolidine-2,4-dione, succinimide, phenylacetylglutamine. The classification modern P.F. is their chemical structure (table. 1).
Anti-convulsants have the ability to warn in experiment on animals spasms caused by electric irritation or the introduction of chemicals (mostly koratala). The selectivity of this effect for some members of P.F. expressed differently. For some substances characterized by similar activity in relation to the experimental seizures or that
of origin, such as phenobarbital (see), geksamidina (see), hlorakona (see), fenacoa (see), phenacemide. And in clinical practice these drugs have proven themselves as P.F. wide actions, is effective in different ways, including mixed forms of epilepsy. Other products are notable selectivity effect. So, against electric shock, the most effective phenytoin (see), Karisalova cramps - trimethadione (see), epomid. Similarly, these P.F. find and in the clinic mainly narrowly focused application: phenytoin - mainly for large seizures, and trimethadione and close to it by the action of epomid - only at small. Thus, the activity on experimental tests with electric shocks and corazolum allows to some extent to predict the scope of the clinical application of a new drug. An important feature is also a sedative effect, clearly have phenobarbital, weakly manifested in hlorakona, trimetina and completely missing the difenina. As a rule, if the patient shows signs of a sedative action (apathy, drowsiness), this indicates a drug overdose.
The mechanism of action of anticonvulsants not clear. One can assume that in the implementation of the anticonvulsant effect plays the role of raising the threshold of excitability of nervous tissue that occurs under the influence of some substances (phenobarbital). However, difenin does not cause increase of the mentioned threshold. Perhaps the mechanism of action of phenytoin is connected with the change of the balance of electrolytes on the level of the membranes of nerve cells, which leads to difficulty distribution convulsive electric discharges on the substance of the brain. Antiepileptic effect trimetina associated with its depressing effect on subcortical structures of the brain.
The use of P.F. in epilepsy is in most cases only one component of the whole complex of therapeutic measures. Appoint P.F. usually inside (when epileptic status resort to intravenous or rectal introduction).
The treatment is long and in each case requires individual selection of the drug and the dose. Most often, a combination therapies. Use combinations of different action anticonvulsants such as phenytoin and trimethadione (when mixed form with large and small seizures), primidone and beclamide (dysphoric form with a tendency to emotional outbursts, aggression). In other cases, resorted to a combination of P.F. with drugs that have positive but non-specific effect on the disease, for example diakarbom (see)that affect acid-base and water balance, brown, magnesium sulfate (see), Merk-hall (see). Anti-convulsants well absorbed from the gastrointestinal tract and undergoes oxidation in the liver, gradually losing lepidopterist and acquiring hydrophilic properties. The oxidation products of P.F. (for substances containing phenyl group, this p-oxyphenylbutazone) convulsants, as a rule, do not possess. The final metabolites P.F. excreted news in the form of soluble in water pair connections with sulfuric or glukuronova acid.
For the treatment of large seizures of epilepsy used phenobarbital (often in combination with caffeine to remove sedative effect), benzonal (see), phenytoin and Trenton, primidone, beclamide. Difenin most effective in patients with large seizures, mentally safe or with minor defects of the mind. Used for the treatment of psychomotor seizures. Close to it by structure trianton shown in the same cases, as difenin, but, unlike the latter, has a mild sedative effect. When assigning geksamidina, especially in patients previously receiving phenobarbital should take into account the absence of a sedative-hypnotic effect inherent in the barbiturates. It allows to increase daily dose, but at bedtime often requires the addition of phenobarbital. Primidone is shown mainly in convulsive forms of epilepsy, and the greatest therapeutic effect is achieved in the case of frequent seizures. Improve mental activities, and mood of patients, increased activity. In most cases, primidone used in combination with other P.F.
Beclamide most effective for different types of atypical of seizures, and fenacon was one of the few tools that help with severe mental epileptic, manifested twilight state with aggression, anxiety and mood disorders. In such cases, but with serious limitations because of the extremely high toxicity is also used phenacemide (tenure). In small fits effective are few of protivosudorozhnykh funds, mainly trimethadione and epomid. Both substances are used mainly in children.
When choosing one or another drug should be guided not only by the selectivity of its action with this form of epilepsy, but also knowledge of equivalent doses of this drug in relation to effective doses of other P.F. For the most common P.F. appropriate relationship described E. C. Remezova (table. 2).
A correct understanding of equieffective doses of P.F. allows to avoid severe acute exacerbations of the disease arising from the cancellation or reduction of the dose of one substance to replace it with another.
For treatment of epileptic status the majority of P.F. not suitable due to poor solubility in water and the inability of parenteral introduction. In this case it is recommended to use geksenal (see). As additional funds apply a combination of chloral hydrate (15-20 ml 6% solution) with the barbitala-sodium (0.5-0.7 g 30-40 ml of distilled water); solutions cooked before consumption and rektalno after cleansing enema. Sometimes prescribed intravenous magnesium sulfate (10 ml of 25% solution) together with sodium bromide (10 to 15 ml of 10% solution).
Anticonvulsant drugs are widely used for the treatment of epilepsy in children's practice, with doses are prescribed depending on the age of the child (table. 3).
Side effects during treatment P.F. occur relatively frequently, which is associated with prolonged use of these substances. Dizziness, headaches, lethargy, drowsiness, nausea,- as a rule, the signs of an overdose of the drug and reduce the dose disappear. More serious side effects skin rash, violations of the parenchymal organs, the defeat of the hematopoietic function (lakopenia, agranulozitos, aplastic anemia fatal). The most dangerous in this respect trimethadione and phenacemide. For some P.F. characterized by such kind of side effects, as photophobia (trimethadione), hyperplastic gingivitis (derived gidantoina).
