my mother (58 yrs) developed mild seizures LHS 10 years after neurosurgery of rt orbital meningoma. She was initially put on oxcarbazepine which was later substituted with phenytoin 300 mg (in 3 divided doses) due to its playing havoc with the electrolyte balance of the body. Now she is still having mild tingling sensation in the left palm and fingers. Is the dosage inadequate?