Neurontin is used off-label for anxiety. It has a very low side effect profile.
From the information I have, 900 mg is typically the dose used for anxiety although Gabapentin is not approved for treating anxiety and there is almost no evidence it is effective so the "best dose" is more of a guess.
The reason it is sometimes used it that it is not a substance of abuse and certain anti-anxiety drugs, benzodiazepines, have a potential for abuse.
You may want to talk with your Dr. about slowing down how quickly you get onto this medication.
I now list Neurontin as a drug I am allergic to as my Dr. switched me from an AD to this medication but forgot to check dosages and I was overdosed on first dose, ended up in ER and an overnight stay in the hospital. So I am very leary of this medication for me.
I hope it works for you.
Kindly,
Kitt