Primidone Tablets

This product is an anti-epileptic drug. Its main metabolite in the body is phenobarbital, which works together. In vitro electrophysiological experiments show that it opens the chloride ion channels of nerve cells and overpolarizes the cells, which is similar to the effect of γ-aminobutyric acid (GABA). At therapeutic concentrations, it can reduce the excitatory effect of glutamate, strengthen the inhibitory effect of γ-aminobutyric acid, inhibit the monosynaptic and polysynaptic transmission of the central nervous system, lead to a decrease in the excitability of the entire nerve cell, and increase the electrical stimulation threshold of the motor cortex. It can increase the threshold of seizures and inhibit the spread of discharges of epileptic foci.

This product contains primidone (C12H14N2O2) which should be 95.0% to 105.0% of the labeled amount.

This product is white tablets.

It is used as a single drug or in combination to treat epileptic tonic-clonic seizures (grand mal seizures), simple partial seizures and complex partial seizures. It is also used to treat essential tremor and senile tremor.

Common dosage for adults: 50 mg before bedtime, change to twice a day after 3 days, change to 3 times a day after a week, change to 250 mg 3 times a day starting from the 10th day, the total amount should not exceed 1.5 g per day; the maintenance dose is generally 250 mg 3 times a day. Common dosage for children: 50 mg before bedtime for children under 8 years old; increase to 50 mg each time, 2 times a day after 3 days; change to 100 mg, 2 times a day after a week; after 10 days, it can be increased to 125 mg~250 mg, 3 times a day according to the situation; or take it in divided doses according to 10~25 mg/kg of body weight per day. Same as adults for children over 8 years old.

1. Patients who cannot tolerate or take an overdose may experience vision changes, diplopia, nystagmus, ataxia, slow cognition, emotional disorders, mental confusion, shortness of breath or disorders. 2. Children and the elderly may experience abnormal reactions such as abnormal excitement or restlessness. 3. Occasionally, allergic reactions (dyspnea, swollen eyelids, wheezing or chest tightness), granulocytopenia, aplastic anemia, erythrocyte dysplasia, and megalocytic anemia may occur. 4. Hand and foot inflexibility may occur or cause unsteady walking, joint contracture, dizziness, and drowsiness. A small number of patients experience sexual dysfunction, headache, loss of appetite, fatigue, nausea or vomiting, but continued use often reduces or disappears. Toxic epidermal necrosis may occur.

Use with caution in the following situations: 1. Patients with impaired liver and kidney function (may cause accumulation of this product in the body). 2. Patients with porphyria (may cause new attacks). 3. Patients with asthma, emphysema or other respiratory diseases that may aggravate dyspnea or airway obstruction. 4. May aggravate mild brain dysfunction.

Precautions for children: Children may experience abnormal reactions such as restlessness and excitement when taking the drug, and it is also easy to cause severe drowsiness and should be used less. Precautions for pregnancy and lactation: Pregnant and lactating women: This product can pass through the placenta and may cause teratogenicity. There are also reports of fetal phenytoin syndrome (growth retardation, craniofacial and cardiac abnormalities, and poor development of nails and knuckles). Vitamin K deficiency can be caused by induction of fetal liver enzymes. Vitamin K should be supplemented in the last month of pregnancy to prevent neonatal bleeding. Patients should minimize combined medication after pregnancy. This product is secreted into breast milk and can cause central nervous system depression or drowsiness in infants. Precautions for the elderly: Elderly patients may experience cognitive dysfunction, restlessness, excitement or drowsiness when taking the drug.

1. When this product is used in combination with alcohol, general anesthetics, drugs with central nervous system depressant effects, and magnesium sulfate for injection, it may increase central nervous system activity or respiratory depression, and the dosage needs to be adjusted. 2. When used in combination with anticoagulants, corticosteroids, digitalis, digoxin, doxycycline hydrochloride, or tricyclic antidepressants, the metabolism of these drugs is accelerated and the efficacy is reduced due to the induction of liver enzymes by phenobarbital. 3. When used in combination with monoamine oxidase inhibitors, the metabolic inhibition of this product may cause poisoning. 4. This product can reduce the intestinal absorption of vitamin B12, increase the excretion of vitamin C by the kidneys, and accelerate the metabolism of vitamin D due to the positive induction of liver enzymes. 5. When used in combination with posterior pituitary hormone, there is an increased risk of arrhythmia or coronary insufficiency. 6. When used in combination with carbamazepine, the efficacy is reduced due to the mutual positive induction of liver enzymes between the two, and the blood drug concentration should be measured. 7. When used in combination with other anti-epileptic drugs, the form of epileptic seizures changes due to metabolic changes, and the dosage needs to be adjusted in time. 8. When used in combination with sodium valproate, the blood concentration of this product increases and the half-life of valproate is shortened. The dosage should be adjusted to avoid poisoning. It should not be used in combination with phenobarbital. The metabolism of this product is accelerated when used in combination with phenytoin sodium. When used in combination with contraceptives, it may cause contraceptive failure.

Light-proof and sealed.

0.25 g

36 months

Shanghai Xinyi Huanghe Pharmaceutical Co., Ltd.

• Founded in:

  1992-08-02

• Address:

  No. 1633, Maixin Road, Xinqiao Town, Songjiang District, Shanghai

• Tax NO.:

  913100006072138387

• Registered Funds:

  56 million yuan

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