Cannot say in your particular case. And, phenytoin is not generally associated with nausea / vomiting unless it is used in relatively high amounts. Itching, also, is not associated with phenytoin. If someone did have increased activity of the central nervous system after an anti=epileptic is suddenly stopped, generally the symptoms would be obviously due to nervous system hyperactivity: nervousness, heart racing, twitching, compulsive movement including scratching. If someone doesn t feel they are hyper, this is unlikley to be occurring. But these symptoms would be declining within a few days and pretty much gone in general in 2 to 4 weeks after it is stopped.