Phenytoin Sodium Tablets

This product is an antiepileptic drug and antiarrhythmic drug. The therapeutic dose does not cause sedation and hypnosis. 1 Animal experiments have shown that this product has a selective antagonistic effect on the tonic phase of super-strong electric shock and convulsion, but is ineffective or even aggravates the spasm phase. Therefore, it is effective for grand mal epileptic seizures, but ineffective for absence seizures. Its antiepileptic mechanism has not yet been elucidated. It is generally believed that it increases the outflow of sodium ions from cells and reduces the inflow of sodium ions, thereby stabilizing the nerve cell membrane, raising the excitation threshold, and reducing the spread of high-frequency discharges in the lesions. 2 In addition, this product shortens the action potential interval and the effective refractory period, and can also inhibit the influx of calcium ions, reduce myocardial automaticity, inhibit the sympathetic center, and have an inhibitory effect on the ectopic rhythm points of the atria and ventricles, increasing the thresholds for atrial fibrillation and ventricular fibrillation. 3 Its stability

The main ingredient of this product is phenytoin sodium, and its chemical name is: 5,5-diphenyl-2,4-imidazolidinedione sodium salt

This product is white tablets or film-coated tablets.

It is suitable for the treatment of generalized tonic-clonic seizures, complex partial seizures (psychomotor seizures, temporal lobe epilepsy), simple partial seizures (localized seizures) and status epilepticus. It can also be used to treat trigeminal neuralgia, recessive dystrophic epidermolysis bullosa, paroxysmal choreoathetosis, paroxysmal control disorders (including behavioral disorders such as anger, anxiety and insomnia due to excessive excitement), myotonia and cardiac conduction disorders in case of overdose of tricyclic antidepressants. This product is also suitable for ventricular and supraventricular arrhythmias caused by digitalis poisoning, and has poor efficacy on arrhythmias caused by various other reasons.

Common dosage for anti-epileptic drugs in adults: 250-300 mg per day, 100 mg at the beginning, twice a day, increase to 250-300 mg within 1-3 weeks, divided into three times for oral administration, the maximum dose is 300 mg once, 500 mg per day. Due to individual differences and saturation pharmacokinetic characteristics, medication needs to be individualized. After the seizures are controlled and the blood drug concentration reaches a steady state, a long-acting (controlled-release) preparation can be used instead, taken all at once. If the seizures are frequent, 12-15 mg/kg can be taken according to body weight, divided into 2-3 times, once every 6 hours, and 100 mg (or 1.5-2 mg/kg according to body weight) can be given from the next day, 3 times a day until the appropriate dose is adjusted. Common dosage for children: Start with 5 mg/kg per day, divided into 2-3 times, adjust as needed, with no more than 250 mg per day.

This product has few side effects, but gingival hyperplasia is common, and the incidence is high in children. Oral hygiene and gingival massage should be strengthened. Long-term use or blood drug concentration reaching 30mu;g/ml may cause nausea, vomiting and even gastritis, which can be alleviated by taking it after meals. Adverse reactions of the nervous system are dose-related, with common symptoms being dizziness and headache. In severe cases, it can cause nystagmus, ataxia, slurred speech and confusion, which can disappear by adjusting the dose or stopping the drug; less common adverse reactions of the nervous system include dizziness, insomnia, transient nervousness, convulsions, chorea, dystonia, tremor, asterixis, etc. It can affect the hematopoietic system, causing granulocytopenia and thrombocytopenia, and rare aplastic anemia;

Contraindications: Patients with a history of allergy to hydantoins or those with heart function impairment such as Ass syndrome, II-III degree atrioventricular block, sinus node block, sinus bradycardia, etc.

Precautions for children: Since the distribution volume and elimination half-life of children change with age, blood drug concentration should be measured frequently. The pharmacokinetics of this product are special for neonates or infants, and it is difficult to clinically assess the symptoms of poisoning. It is generally not used first. Preschool children have strong liver metabolism, and blood drug concentration needs to be monitored multiple times to determine the frequency and dosage of medication. Precautions for pregnancy and lactation: This product can pass through the placenta and may cause teratogenesis, but it is believed that the risk of teratogenesis due to uncontrolled epileptic seizures is greater than the risk of medication. The pros and cons should be weighed. Patients who can control seizures with this product should continue to take it during pregnancy and maintain blood concentration, and then readjust after delivery. Vitamin K should be supplemented one month before delivery, and vitamin K should be injected into the newborn immediately after delivery to reduce the risk of bleeding. This product can be secreted into breast milk, and it is generally recommended that mothers taking phenytoin sodium avoid breastfeeding. Precautions for the elderly: The incidence of chronic hypoproteinemia in the elderly is high, and there are many combined medications in treatment, and the interactions between drugs are complex. Be cautious when using this product, and the dosage should be low. And monitor blood drug levels frequently.

① Long-term use of acetaminophen in patients may increase the risk of liver poisoning and reduce the efficacy of this product; ② It is a liver enzyme inducer. When used in combination with corticosteroids, digitalis (including digoxin), oral contraceptives, cyclosporine, estrogen, levodopa, quinidine, oxytetracycline or tricyclic antidepressants, the effects of these drugs may be reduced; ③ Long-term drinking can reduce the concentration and efficacy of this product, but drinking a lot of alcohol while taking the medicine can increase the blood concentration; combined with chloramphenicol, isoniazid, phenylbutazone, and sulfonamides may reduce the metabolism of this product and increase the blood concentration, increasing the toxicity of this product; when used in combination with anticoagulants, the anticoagulant effect is initially increased, but it is reduced with continuous use; ④ When used in combination with drugs containing magnesium, aluminum or calcium carbonate, the bioavailability of this product may be reduced, and the two should be taken 2 to 3 hours apart; ⑤ When used in combination with hypoglycemic drugs or insulin, because this product can increase blood sugar, the dosage of the latter two needs to be adjusted; ⑥ In principle, patients using dopamine should not use this product; ⑦ When this product is used in combination with lidocaine or propranolol, it may enhance the inhibitory effect on the heart; ⑧ Although this product consumes folic acid in the body, increasing folic acid can reduce the concentration and effect of this product; ⑨ The effects of phenobarbital or primidone on this product vary greatly, and blood drug concentrations should be monitored frequently; when used in combination with valproic acid, there is a protein binding competition, and blood drug concentrations should be monitored frequently to adjust the dosage of this product. ⑩ When used in combination with carbamazepine, the latter has a lower blood concentration. If a large amount of antipsychotics or tricyclic antidepressants are used in combination, epileptic seizures may occur, and the dosage of this product needs to be adjusted.

Keep away from light and store in airtight container.

0.1g

36 months