Hello
The normal dose of GABAPENTINE in neurological pain is 300 to 600 mg three times in a day for prolong period .
As you father is receiving 100 mg and he was diagnosed as a patient of
DEMENTIA .
These are side effects of gabapentin .
Somnolence (
drowsiness ) ,
dizziness , ataxia , weakness , parasthesia , fatigue, headache ,
nystagmus , diplopia , nausea , vomiting , weight gain,
dyspepsia , rhinitis , tremor , leucopenia , altered liver function tests, Steven's Jhonson's syndrome .
I am also prescribing this drug so many patients but I have never noted dementia in my patient .
So in my opinion consult your treating doctor and get his opinion regarding dementia .
Hope this information will be helpful for you.