Antiepileptic drugs

Content

Introduction

Antiepileptic drugs, or anticonvulsants, do not cure epilepsy or its causes, but are used for preventive purposes to reduce the frequency and severity of seizures.

These drugs are able to modify, with different mechanisms, the levels of chemicals present in the brain that regulate the brain's electrical activity, managing to control seizures in 70% of cases.

Antiepileptic therapy is generally used in the presence of repeated seizures and seizures or if a specific form of epilepsy has been ascertained (diagnosed). However, antiepileptics can also be prescribed after a single seizure, which does not necessarily imply the presence of the disease, if there is a "high probability that the seizures may recur as could happen, for example, if there are other people in the family with "epilepsy.

For more information on the active ingredients named in the contribution or in any case belonging to this class of drugs, you can visit the website of the Italian Medicines Agency (AIFA) by clicking HERE. To search for a drug using the trade name and not the active ingredient, you can click HERE. Inside the site you can find all the package leaflets of the drugs and also some additional information. If "revoked" is written next to the drug name, the drug is no longer on the market.

Choice of drug

The choice of an antiepileptic over another is rather delicate and complex (List of the main active ingredients used as antiepileptic drugs and their therapeutic indications).

To determine which is the most appropriate drug, among the many currently available, the doctor will have to consider several parameters:

  • type of crisis with which the disease occurs
  • sex
  • age
  • lifestyle
  • presence of other diseases
  • use of other drugs

The goal of therapy is to control seizures with as few undesirable effects (side effects) as possible. Therefore, at least initially, only one antiepileptic drug (monotherapy) is administered, since the combination of several drugs increases the risk of potential undesirable effects and the possibility of reactions due to the use of several drugs at the same time (drug interaction).

In about half of the cases, seizure control is achieved with the first drug used. If the antiepileptic of first choice is not effective, another attempt is made with a second drug, always in monotherapy. In case of further failure, in general, polytherapy is used directly, that is to say the association of two or more drugs whose mechanisms of action, although different, are complementary. Where even polytherapy does not allow satisfactory control of crises, it is necessary to consider surgery or a treatment other than pharmacological.

How to take antiepileptics

Antiepileptics, available in the form of tablets, capsules, oral solutions and syrups, must be taken at regular intervals in several daily doses (usually 1 to 3 times a day), strictly respecting the doctor's prescriptions. Simply forgetting a dose increases the likelihood of seizures occurring.

Therapy is long-term.It typically lasts for several years but, in some cases, it can continue for a lifetime.

Normally we start with low dosages, which are gradually increased until the recommended maintenance dose is reached, corresponding to the minimum dose that allows to block the onset of seizures. The use of low initial dosages, to be increased in successive stages, allows the "body to get used to the drug, thus reducing the risk of unwanted effects (side effects).

The maintenance dose, calculated on the basis of body weight and age, depends on the type of antiepileptic used. The time required to reach the maintenance dose can be a few weeks or months, depending on the individual response to therapy. The doctor may, however, decide to increase or reduce the dose of the drug, with respect to the maintenance dose, based on the trend of the seizures and the possible appearance of unwanted effects.

In case of insufficient seizure control, the dose can be increased up to the maximum tolerated dose; if, on the other hand, unpleasant side effects occur, the dose must be reduced until the symptoms subside.

Interactions

Interaction with other drugs

Some medicines used to treat other diseases, other than epilepsy, can interact with antiepileptic drugs, reducing their effectiveness, increasing the risk of seizures, or enhancing their side effects.

Before starting therapy with other drugs, including over-the-counter or herbal products and supplements, you should seek the advice of your doctor or pharmacist, avoiding self-medication.

Drugs capable of interacting with antiepileptics include:

  • antibiotics
  • benzodiazepines
  • antipsychotics
  • analgesics
  • steroids

Interaction with grapefruit

According to the results of some researches, grapefruit, squeezed or consumed whole, increases the concentration in the blood of various drugs causing an effect similar to overdose and exposing you to a high risk of the appearance of side effects. Antiepileptic drugs that grapefruit can interfere with are:

  • carbamazepine
  • diazepam
  • midazolam

Contraception

Some antiepileptic drugs can reduce the effectiveness of the contraceptive pill. To avoid unwanted pregnancies, it is advisable to use formulations with a high estrogen content or to use additional methods of contraception, such as the use of condoms, or alternatives, such as intrauterine devices.
In turn, the pill can interact with some antiepileptics, reducing their concentration in the blood and increasing the risk of seizures.

Blood tests

During the therapy, the doctor may prescribe the execution of some samples to measure the level of antiepileptic drug present in the blood. blood dosage, generally carried out in the following cases:

  • check the correct intake of the drug, according to the prescribed doses and methods
  • presence of side effects, could be linked to too high a dosage
  • pregnancy, recent birth or other physiological conditions, may require dosage adjustment
  • introduction of another antiepileptic, it may interfere with the one you are using
  • medications taken for other diseases, could interact with antiepileptic therapy
  • replacing a brand-name drug with a generic one and vice versa

Side effects

Antiepileptics, like all drugs, can cause unwanted effects. Some appear immediately and tend to resolve spontaneously with the continuation of therapy, while others may appear several weeks or months after the start of treatment.

The specific side effects of each antiepileptic are indicated in the package leaflet included in the package of the medicine.

In general, the most common undesirable effects (side effects) are:

  • drowsiness
  • nausea and vomit
  • tiredness (asthenia)
  • headache
  • state of agitation and nervousness
  • uncontrollable tremor
  • hair loss (alopecia) or abnormal hair growth (hirsutism)
  • swelling of the gums (gingival hypertrophy)

In very rare cases, the following side effects may occur:

  • depression
  • suicidal thoughts and behaviors
  • inflammation of some organs, such as the liver

Some disorders, such as instability with loss of balance, difficulty concentrating and vomiting, could be caused by too high doses.

The appearance of skin reactions could indicate an allergy to the drug which requires immediate discontinuation of therapy.

In the presence of these or other disorders, you must contact your doctor without hesitation who, depending on the case, may decrease the dosage of the drug or replace it with an alternative antiepileptic.

Pregnancy

The use of some antiepileptics during pregnancy may increase the risk of birth defects (congenital) such as spina bifida, cleft lip and some heart abnormalities, as well as the development, during development, of disturbances in reasoning, memory , language (disturbances of the cognitive sphere). Moreover, the suspension of the therapy is not recommended since uncontrolled crises dangerous for the health of the mother and the fetus could occur.

The pregnancy, therefore, should be planned together with the gynecologist and the treating neurologist who will be able, before conception, to fine-tune the treatment, minimizing the risks for the fetus.

The neurologist, for example, in the case of polytherapy could reduce the number of drugs, replace the antiepileptic in use with a drug that has a higher safety profile for the fetus, divide the daily dose of the antiepileptic into several doses using, in in any case, the minimum amount effective to control seizures. Furthermore, at least for the three months preceding conception and for the first trimester of pregnancy, it could prescribe the intake of folic acid. Folic acid, in fact, seems to protect the unborn child from congenital malformations, improving, at the same time, neurocognitive development. .

If you realize you are pregnant it is essential to inform the neurologist immediately because the physiological changes caused by gestation, such as weight gain and body fluids, could reduce the concentration of the drug in the blood. , to periodically check the amount of drug present in the blood and to adjust the dosages, if necessary.

Suspension of treatment

If the seizures do not occur for at least 2 consecutive years the neurologist may consider stopping the drug.

The decision to continue the treatment or not is up to the doctor, in consultation with the person and his family, taking into account some determining factors to assess the risk of relapses (relapses). They include:

  • duration of the seizure-free period prior to suspension, the longer the crisis-free period, the lower the chances of relapse
  • number of drugs used, treatment with more than one antiepileptic exposes you to a greater risk of recurrence of seizures
  • number of epileptic episodes that occurred, the greater the number of seizures, the greater the risk that they may reappear
  • age at which the disease appeared, some forms of childhood epilepsy tend to regress spontaneously before adulthood
  • type of epilepsy, the risk of relapse is high in some forms of epilepsy, such as juvenile myoclonic epilepsy (a short and involuntary contraction of a muscle or group of muscles)

Any suspension of the treatment will take place over a few months, progressively reducing the doses of the drug. In the case of combined therapy (polytherapy), the drug considered less effective will be discontinued first.

Equivalent drugs and epilepsy

There Italian League Against Epilepsy (LICE), which brings together Italian specialists dealing with epilepsy, has formulated some recommendations on the use of equivalent (or generic) drugs in the treatment of epilepsies:

  • when starting therapy (initial monotherapy, replacement monotherapy or additional therapy), patients should be informed of the possible existence of generic products that represent a valid choice in patients starting treatment
  • ongoing treatment with disappearance of the crises, in cases where complete remission of the seizures has already been achieved, it is not recommended to replace the drug taken, be it brand or generic. The medical prescription must, therefore, explicitly contain the indication of the non-substitutability of the drug
  • ongoing treatment with crises still present, the generic drug can replace the brand name, with the consent of the person
  • ongoing treatment with generic drug, in people being treated with a generic drug, it is not recommended to replace it with a generic from another manufacturer. The prescription of the drug must therefore clearly indicate the manufacturer of the chosen generic
  • the substitution of modified-release antiepileptic drugs with immediate release drugs should be avoided
  • for some patients, in very special cases, the replacement of the branded drug with a generic one may not be indicated for specific reasons which must be indicated by the attending physician

In all cases in which replacement is necessary, it is advisable to check the concentration in the blood of the drug taken.

Bibliography

NHS. Epilepsy (English)

Epilepsy Action. Advice and information (English)

In-depth link

SNLG Regions Guidelines. Diagnosis and treatment of epilepsies. Tuscany Region, 2014

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