My 4 month old boy is having seizures, is Eptoin (Phenytoin) the right treatment?

Hello doctor,
My son 4month old having weight 8.3 kg. Is this over weight according to age.
My son had a seizure 3 times in 15 days.
On 15th Eve he had 3rd seizure of approx. 1 min. On 16th day morning he had 4th seizure of 1 and half min. After that we took away to doctor ,he asked for blood test in which calcium was little bit more. Then they asked for EEG and at that time another seizure took place of same duration. Then they admitted for a day for observation.but only 3-5 second of seizure took place. Then they discharge and told us to give 3 and half ml of eptoin twice a day for 15 days now.

Details of seizure – eyes went up, strengthens the body, strengthens hands and legs straight, body shakes.

Does their any serious problem. Is this eptoin syrup OK for my son