Seizar, tablets 50 mg 30 pcs

Lamotrigine is a blocker of potential-dependent sodium channels. It reduces pathological activity of neurons without suppressing their function. It stabilizes neuronal membranes through its effect on Na+channels, blocks excessive glutamate release without reducing its normal release.

Pharmacokinetics

Absorption. Lamotrigine is rapidly and completely absorbed from the intestine, undergoing virtually no presystemic first-pass metabolism. Maximum plasma concentration is reached approximately 2.5 hours after oral administration. The time to reach maximum concentration is slightly longer after meals, but the degree of absorption remains unchanged. Pharmacokinetics is linear with a single dose of up to 450 mg (the highest dose studied). Significant interindividual variation in maximum equilibrium concentration is observed, however, with rare variations in each individual.
Distribution. Lamotrigine binds to plasma proteins by approximately 55%. It is unlikely that release of the drug from protein binding can lead to the development of toxic effects. The volume of distribution is 0.92-1.22 L/kg.
Metabolism. The enzyme uridine diphosphate-glucuronyltransferase (UDF-glucuronyltransferase) is involved in the metabolism of lamotrigine. Lamotrigine increases its own metabolism to a small extent in a dose-dependent manner. However, there is no evidence that lamotrigine affects the pharmacokinetics of other antiepileptic drugs and that interactions are possible between lamotrigine and other drugs metabolized by the cytochrome P450 system.
Excretion. In healthy adults, lamotrigine clearance at equilibrium concentrations averages 39±14 mL/min.
Lamotrigine is metabolized to glucuronides, which are excreted by the kidneys. Less than 10% of the drug is excreted unchanged by the kidneys, about 2% – by the intestine. Clearance and elimination half-life do not depend on the dose. Half-life in healthy adults is on average 24 hours to 35 hours. In patients with Gilbert’s syndrome a decrease in drug clearance by 32% was observed compared to the control group, which, however, was within normal values for the general population.
The half-life of lamotrigine is greatly influenced by the drugs taken together.
The average half-life is reduced to approximately 14 h when co-administered with glucuronizing drugs such as carbamazepine and phenytoin, and increased to an average of 70 h when co-administered with valproic acid.
Special patient groups
Children
In children lamotrigine clearance per body weight is higher than in adults; it is highest in children under 5 years of age. The elimination half-life of lamotrigine in children is usually shorter than in adults. It averages approximately 7 h when concomitantly administered with glucuronizing agents such as carbamazepine and phenytoin and increases to an average of 45-50 h when concomitantly administered with valproic acid.
Elderly patients
No clinically significant differences in lamotrigine clearance have been found in elderly patients compared to younger patients.
Patients with impaired renal function
If renal function is impaired, the initial dose of lamotrigine is calculated according to the standard antiepileptic drug regimen. A dose reduction may be required only if renal function is significantly impaired.
Patients with impaired hepatic function
The initial, increasing, and maintenance doses should be reduced by approximately 50% in patients with moderate hepatic impairment (Child-Pugh stage B) and by 75% in patients with severe hepatic impairment (Child-Pugh stage C). Dose increases and maintenance doses should be adjusted according to clinical effect.
Clinical efficacy in patients with bipolar disorder
Efficacy in preventing mood disorders in patients with bipolar disorder has been demonstrated in two basic clinical studies.
Combined analysis of the findings found that duration of remission, defined as time before first episode of depression and before first episode Duration of remission was more pronounced for depression.

Indications

Active ingredient

Composition

How to take, the dosage

In oral administration for adults and children over 12 years of age, the initial single dose is 25-50 mg, with maintenance doses of 100-200 mg/day. In rare cases, doses of 500-700 mg/day may be required.

In children aged 2 to 12 years, the starting dose is 0.2-2 mg/kg/day and the maintenance dose is 1-15 mg/kg/day.

The maximum daily dose for children aged 2 to 12 years, depending on the treatment regimen used, is 200-400 mg.

The frequency of dosing and the intervals between doses depend on the treatment regimen used and the patient’s response to the ongoing treatment.

Interaction

In concomitant use with anticonvulsants – inducers of metabolism in the liver (including phenytoin, carbamazepine, phenobarbital, primidone) the metabolism of lamotrigine is accelerated.

The concomitant use of lamotrigine and carbamazepine or phenytoin decreases the T1/2 of lamotrigine. There have been reports of dizziness, ataxia, diplopia, blurred vision and nausea in patients taking carbamazepine after starting treatment with lamotrigine.

Due to inhibition of hepatic microsomal enzymes by sodium valproate, concomitant use slows down lamotrigine metabolism and increases T1/2 of lamotrigine.

Special Instructions

With caution, use in patients with renal insufficiency.

Lamotrigine should not be used in elderly patients.

Lamotrigine should be discontinued if there are significant skin allergic reactions.

If lamotrigine is withdrawn suddenly, epilepsy manifestations may worsen, so treatment should be gradually discontinued, reducing the dose over 2 weeks.

Concomitant use with carbamazepine may cause dizziness, diplopia, ataxia, visual disturbances, and nausea. These phenomena usually disappear with reduction of the carbamazepine dose.

Lamotrigine should not be used in children under 2 years of age.

Impact on the ability to drive and operate machinery

During treatment there is a slowing down of psychomotor reactions. This must be taken into account by those engaged in potentially hazardous activities requiring increased attention and quick psychomotor reactions.

Contraindications

Hypersensitivity to lamotrigine or any component of the drug. Children under 3 years of age (for this dosage form).

With caution
Chronic renal failure, allergic reactions or skin rash to other antiepileptic drugs in the history.

Side effects

CNS disorders: headache, dizziness, drowsiness, sleep disturbances, fatigue, aggressiveness, confusion.

Digestive system disorders: nausea, liver function disorders.

Hematopoietic system disorders: leukopenia, thrombocytopenia.

Allergic reactions: skin rash (usually maculopapular), angioedema, Stevens-Johnson syndrome, toxic epidermal necrolysis, lymphadenopathy.

Overdose

There have been reports of single doses exceeding the maximum therapeutic doses by a factor of 10-20.

Symptoms: nystagmus, ataxia, impaired consciousness to coma.

Treatment: Hospitalization and appropriate symptomatic therapy. In case of recent (less than 2 h) ingestion of the drug, gastric lavage should be performed.

Pregnancy use

Clinical data on the safety of lamotrigine administration during pregnancy and lactation are insufficient.

The expected benefit to the mother and the potential risk to the fetus should be weighed when deciding whether to use in pregnancy.

Preliminary data show that lamotrigine penetrates into breast milk at a concentration of 40-45% of the plasma concentration. No adverse effects have been noted in a small number of infants whose mothers received lamotrigine.

Pediatric use

Lamotrigine should not be used in children less than 2 years of age.

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