Eptoin Injection contains Phenytoin sodium at a concentration of 50mg per 2ml and is indicated for the management and prevention of seizures, particularly in patients with epilepsy. Phenytoin is an antiepileptic agent that stabilizes neuronal membranes and decreases seizure activity by promoting sodium efflux from neurons in the motor cortex, thereby reducing repetitive neuronal firing. Eptoin Injection is primarily used in acute settings for the control of generalized tonic-clonic (grand mal) seizures and complex partial seizures when oral administration is not feasible. It is administered intravenously or intramuscularly under strict medical supervision, with dosage individualized based on patient response and serum phenytoin levels to avoid toxicity. Common adverse effects include dizziness, nystagmus, ataxia, and gingival hyperplasia with prolonged use. Serious adverse reactions may involve hypersensitivity, cardiac arrhythmias, and Stevens-Johnson syndrome. Caution is advised in patients with hepatic impairment, cardiovascular disorders, or hypersensitivity to phenytoin. Drug interactions are significant due to phenytoin’s enzyme-inducing properties, necessitating careful monitoring when co-administered with other medications. Eptoin Injection should be used only under professional medical guidance, with continuous monitoring of neurological status and serum drug concentrations to ensure therapeutic efficacy and minimize adverse effects.