The cause of drowsiness in this case can be due to either medicines or some metabolic derangement like low blood sodium levels, which occur in many elderly patients during or after critical illnesses. The normal levels of drugs (Phenytoin and Sodium Valproate) do not rule out the possibility that the patient may be intolerant to these doses. Sometimes the combination of two drugs can make the patient drowsy. If blood sodium levels are low, they should be corrected. If the patient's MRI Brain, EEG and routine blood tests were normal, it would be advisable to gradually reduce the doses of either phenytoin or valproate (not both) under supervision. If MRI or EEG is abnormal, the drugs should be changed under supervision.Epilepsy by definition is an unpredictable illness, and the seizures may occur anytime, even in a patient who is well controlled for years. There are certain factors which increase the chances of patient having a seizure like fasting, lack of sleep, mental stress, some medicines like ciprofloxacin or chloroquine, fever etc. and these should be strictly avoided.