Overdose of phenytoin sodium at present there is no effective antidote, can only be reduced or discontinued and according to the symptoms of the symptomatic supportive treatment, such as gastric lavage, infusion to correct the water electrolyte disorders and so on. 1. Phenytoin sodium can selectively inhibit the cerebral cortex motor area, the main mechanism is to stabilize the brain cell membrane and increase the inhibitory neurotransmitter such as γ-aminobutyric acid (GABA) in the brain to prevent abnormal brain nerve discharge. Clinically, it is mainly used in the treatment of epilepsy. 2. When phenytoin sodium is overdosed, blurred or double vision, unsteady walking, confusion, severe dizziness or drowsiness, and even hallucinations, nausea and vomiting, and slurred speech will occur. 3. When an overdose is found or the above symptoms occur, stop using the drug immediately and go to the hospital for medical treatment, which can be given to induce vomiting or gastric lavage to promote the discharge of residual drugs in the digestive tract. If circulatory, respiratory and central nervous system depression occurs, vasoactive drugs, oxygen, ventilator and other supportive treatments should be given, and hemodialysis can be taken to remove the drug components in the blood if necessary. 4. Phenytoin sodium is contraindicated in patients who are allergic to the components of the drug, patients with Asperger’s syndrome, sinus bradycardia, sinus node block, and patients with 2nd or 3rd degree atrioventricular block. In case of overdose of phenytoin sodium, stop using the drug immediately and go to the hospital, standardize the treatment under the guidance of physicians to avoid adverse consequences.