What Is Phenytoin Toxicity?
Phenytoin sodium has a highly selective inhibitory effect on the cerebral cortex motor area. It is generally believed to stabilize the function of the brain cell membrane and increase the inhibitory neurotransmitters serotonin (5-HT) and -aminobutyric acid in the brain. (GABA), to prevent the spread of abnormal discharges and have antiepileptic effects. The mechanism of anti-neuralgia may be related to the effect of this product on the central nervous system, reducing synaptic transmission or reducing transient stimuli that cause neuron discharge. It can also inhibit the ectopic rhythm of the atria and ventricles, can also accelerate the conduction of the atria, reduce myocardial autonomy, and have an antiarrhythmic effect.
Basic Information
- Drug Name
- Phenytoin sodium
- Alias
- Big lentin
- Foreign name
- PHENYTOIN SODIUM
- Whether prescription drugs
- prescription
- Main indications
- Epilepsy first choice
- Dosage
- Follow the doctor's order
- Dosage form
- Tablets: 50mg, 100mg each;
- Athletes use with caution
- Use with caution
- Whether to include health insurance
- Incorporate
- Storage
- Protect from light
Indication of phenytoin sodium
- 1. Mainly applicable to the treatment of complex partial seizures (temporal lobe epilepsy, psychomotor seizures), simple partial seizures (localized seizures), generalized tonic-clonic seizures, and persistent epilepsy. This product is slow to reach effective concentration in brain tissue, so the effect appears slow, and it needs to be taken several times in a row to be effective.
- 2. Treatment of trigeminal neuralgia and sciatica, paroxysmal choreography, paroxysmal control disorders, myotonia, and recessive dystrophic bullous epidermolysis.
- 3. For the treatment of supraventricular or ventricular premature beats, ventricular tachycardia, especially for ventricular tachycardia during cardiac glycoside poisoning, supraventricular tachycardia is also available.
Clinical application of phenytoin sodium
- Oral: 250-300mg / day, divided into 2 or 3 times, the maximum amount is 300mg / time, 500mg / day; intravenous injection: 100-250mg / time (not more than 50mg / min), the total amount does not exceed 500mg / day. It is used for ventricular and supraventricular arrhythmias caused by cardiac conduction disorder and digitalis poisoning when tricyclic antidepressants are overdose. Oral: 100-300mg / day, divided into 1-3 times; intravenous injection: stop arrhythmia 100mg / Times, 10 to 15 minutes can be repeated until the arrhythmia ceases or adverse reactions occur, the total amount does not exceed 500mg / day. Children begin to use 5mg / kg daily, divided into 2 to 3 times, the maximum amount does not exceed 250mg / day; maintenance amount is 4 to 8mg / kg daily, divided into 2 to 3 times used. For collagenase synthesis inhibitors, taken orally: starting at 2 ~ 3mg / kg daily, divided into 2 doses, and increased to a dosage that the patient can tolerate within 2 ~ 3 weeks, with a blood concentration of at least 8g / ml.
Phenytoin sodium adverse reactions
- The more common adverse reactions are behavioral changes, clumsiness or unstable gait, confused thinking, articulation, hand tremor, nervousness, or irritability. These reactions are often reversible and disappear quickly after stopping the drug. In addition, there are more common gum hypertrophy, bleeding, rough face, and hair growth. Occasionally, cervical or axillary lymphadenopathy (decreased IgA), fever or rash (intolerance or allergies), leukocytopenia, and purpura. Rarely cause toxic cataract in both eyes, amenorrhea, cerebellar damage, atrophy. The US FDA has released phenytoin sodium that can cause potentially serious skin lesions such as SJ syndrome and toxic epidermal necrolysis (TEN), especially among Asian populations, including Chinese Han Chinese.
Precautions for phenytoin sodium
- Overdose may cause blurred vision or double vision. Prolonged sudden arrest can exacerbate epilepsy or induce a state of epilepsy.
Contraindications of phenytoin sodium
- It is contraindicated in patients with a history of allergies to hydantoin drugs, asthma syndrome, atrioventricular block to degree, sinus node block, and sinus bradycardia.
Phenytoin sodium drug interactions
- 1. Combined with coumarins (especially dicoumarin), chloramphenicol, isoniazid, butazone, and sulfa drugs, the metabolism of phenytoin sodium decreases, blood concentration increases, and toxicity increases.
- 2. Combined with carbamazepine, adrenocortical hormone, cyclosporine, digitoxin, estrogen, levodopa or quinidine, phenytoin induces liver metabolic enzymes, which reduces the efficacy of these drugs.
- 3. Long-term use of acetaminophen in patients with this product can increase the risk of liver poisoning and reduce the efficacy.
- 4. When combined with magnesium, aluminum or calcium carbonate, it may reduce the bioavailability of this product.
- 5. When combined, it reduces the protein binding rate of valproic acid, which increases its effect or toxicity.
- 6. Long-term drinking can reduce the concentration and efficacy of this product, but taking a large amount of alcohol while taking the drug can increase the blood concentration.
- Note: The above content is only for introduction, the drug use must be carried out by a regular hospital under the guidance of a doctor.