Levetiracetam Tablets

Pharmacological action: Levetiracetam is a pyrrolidone derivative whose chemical structure has no correlation with existing antiepileptic drugs. The exact mechanism of levetiracetam's antiepileptic effect is still unclear. The antiepileptic effect of levetiracetam has been evaluated in a variety of animal models of epilepsy. Levetiracetam has no inhibitory effect on simple epileptic seizures induced by maximum stimulation of electric current or multiple convulsants, and only shows weak activity in submaximal stimulation and threshold tests. However, a protective effect was observed on generalized seizures secondary to focal seizures induced by pilocarpine and kainic acid. These two chemical convulsants can mimic the characteristics of some people's complex partial seizures with secondary generalized seizures. Levetiracetam has an inhibitory effect on both the ignition process and the ignition state of the rat ignition model of complex partial seizures. The predictive value of these animal models for specific types of epilepsy in humans is still unclear. In vitro and in vivo experiments showed that levetiracetam inhibited hippocampal epileptiform burst discharges, but had no effect on the excitability of normal neurons, suggesting that levetiracetam may selectively inhibit the hypersynchrony of epileptiform burst discharges and the propagation of epileptic seizures. Levetiracetam has no affinity for a variety of known receptors at concentrations as high as 10uM, such as benzodiazepines, GABA, glycine, NMDA, reuptake sites, and second messenger systems. In vitro experiments showed that levetiracetam had no effect on neuronal voltage-gated sodium channels or T-type calcium currents. Levetiracetam does not directly facilitate GABAergic neurotransmission, but studies have shown that it has an antagonistic effect on the activity of negative regulators of GABA and glycine-gated currents in cultured neurons. Saturable and stereoselective neuronal binding sites for levetiracetam were found in rat brain tissue, but the identification and function of the binding site are currently unclear.

The chemical name of levetiracetam is (S)-alpha;-ethyl-2-oxo-1-pyrrolidineacetamide, molecular formula: C8H14N2O2, molecular weight: 170.21.

This product is an oval film-coated tablet (250 mg is a blue tablet, 500 mg is a yellow tablet, and 1000 mg is a white tablet), which appears white after removing the coating.

For adjunctive treatment of partial seizures in adults and children over 4 years of age with epilepsy.

(1) Route of administration: Oral. It needs to be swallowed with an appropriate amount of water, and the administration is not affected by eating. (2) Administration method and dosage: The initial treatment dose for adults (18 years old) and adolescents (12-17 years old) weighing ≥50kg is 500mg each time, twice a day. Based on clinical effects and tolerability, the daily dose can be increased to 1500mg each time, twice a day. The dose should be increased or decreased by 500mg/time, twice a day every 2-4 weeks. For the elderly (≥65 years old), adjust the dose according to renal function (see the description of patients with impaired renal function below for details). The initial treatment dose for children aged 4-11 years and adolescents (12-17 years old) weighing ≤50kg is 10mg/kg, twice a day. Based on clinical

The safety data summarized from adult clinical studies showed that the incidence of adverse reactions in the drug group and the placebo group were similar, at 46.4% and 42.2%, respectively. Among them, serious adverse reactions were 2.4% and 2.0%, respectively. The most common adverse reactions are drowsiness, fatigue, and dizziness, which often occur at the beginning of treatment. Over time, the incidence and severity of adverse reactions related to the central nervous system will decrease accordingly. There is no obvious dose-relatedness for the adverse reactions of levetiracetam. Clinical studies in children (4-16 years old) showed that the incidence of adverse reactions in the drug group and the placebo group were similar, at 55.4% and 40.2%, respectively, and no serious adverse reactions occurred in the drug group (1.0% in the placebo group). The most common adverse reactions in children are drowsiness, hostility, and nervousness.

Patients who are allergic to levetiracetam or to pyrrolidone derivatives or any other ingredients are contraindicated to use this product. (A derivative is a compound formed by replacing atoms or atomic groups in the parent compound molecule with other atoms or atomic groups, which is called a derivative of the parent compound. When naming derivatives, the original parent compound is generally used as the main body, and other groups are used as substituents.)

In vitro data show that levetiracetam and its major metabolites are neither inhibitors of human liver cytochrome P450, epoxide hydrolase or uridine diphosphate-glucosidase nor substrates with high affinity at concentrations above the Cmax level obtained within the therapeutic dose range. Therefore, pharmacokinetic interactions are not likely to occur. In addition, levetiracetam does not affect the in vitro glucosidase action of valproic acid. Levetiracetam has a low plasma protein binding rate (10%) and is not likely to produce clinically significant interactions due to competition with other drugs for protein binding sites. Potential pharmacokinetic interactions between drugs were evaluated by pharmacokinetic screening in clinical pharmacokinetic studies (phenytoin, sodium valproate, oral contraceptives, digoxin, warfarin and probenecid) and placebo-controlled clinical trials. Drug-drug interactions between levetiracetam and other antiepileptic drugs (AEDs): Phenytoin levetiracetam (3000 mg daily) has no effect on the pharmacokinetic properties of phenytoin in patients with refractory epilepsy. The use of phenytoin also does not affect the pharmacokinetic properties of this product. Sodium valproate levetiracetam (1500 mg, twice daily) does not change the pharmacokinetic properties of sodium valproate in healthy volunteers. Sodium valproate 500 mg, twice daily, does not change the rate or extent of levetiracetam absorption, or its plasma clearance, or urinary excretion. It also does not affect the exposure level and excretion of major metabolites. The serum concentrations of levetiracetam and other antiepileptic drugs (carbamazepine, gabapentin, lamotrigine, phenobarbital, phenytoin, deoxyphenobarbital and sodium valproate) obtained in placebo-controlled clinical studies were evaluated, and the data showed that levetiracetam did not affect the blood concentrations of other antiepileptic drugs. These commonly used antiepileptic drugs also do not affect the pharmacokinetic properties of this product. The effect of antiepileptic drugs in pediatric patients taking enzyme-inducing antiepileptic drugs at the same time, the apparent total clearance of this product in vivo increased by about 22%. However, no dose adjustment is required. Levetiracetam does not affect the plasma drug concentrations of carbamazepine, sodium valproate, topiramate or lamotrigine. Other drug interactions: Oral contraceptives Taking levetiracetam (500 mg, twice daily) did not affect the pharmacokinetic properties of oral contraceptives containing 0.03 mg ethinyl estradiol and 0.15 mg levonorgestrel, or the levels of luteinizing hormone and progesterone, indicating that this product does not affect the efficacy of contraceptives. The use of oral contraceptives does not affect the pharmacokinetic properties of this product. Digoxin Taking levetiracetam (1000 mg, twice daily) does not affect the pharmacokinetic and pharmacodynamic (ECG) properties of a daily dose of 0.25 mg digoxin. The use of digoxin does not affect the pharmacokinetic properties of this product. Warfarin Taking levetiracetam (1000 mg, twice daily) does not affect the pharmacokinetic properties of R and S warfarin. Coagulation time is not affected by levetiracetam. The use of warfarin does not affect the pharmacokinetic properties of this product. Probenecid (500 mg, 4 times a day) is a tubular secretion blocker that inhibits the renal clearance of the main metabolites of levetiracetam, but not the pharmacokinetic properties of levetiracetam (1000 mg, 2 times a day), but the concentrations of these metabolites are very low. Other drugs that need to be cleared by tubular secretion will also affect the renal clearance of metabolites. There are currently no studies on the combined use of levetiracetam and probenecid. The effect of levetiracetam combined with other actively secreted drugs on the efficacy (such as nonsteroidal anti-inflammatory drugs, sulfonamides and methotrexate) is still unclear.

Keep away from light and store in sealed container.

0.5 g

0 month