Gabapentin For Dogs – How It Works, the Dosage and Side Effects. None of us want our dogs to suffer, but medications can also be worrisome. Pain medications almost always come with overdose risks, and the potential for side effects. You don't say how often you are taking this medication. It only has a half life of 8 hours, consequently the usual dose is 300 mg three times daily. Gabapentin for Anxiety: Does It Work and How Long Will It Take? The drug gabapentin is perhaps best recognized by the brand name Neurontin, but numerous generic versions of gabapentin exist. Gabapentin was developed to be an approximate synthetic version of the neurotransmitter GABA or gamma-aminobutyric acid. Neurontin (gabapentin) spends plenty of time in our patient’s medicine cabinets, but lately it has spent nearly as much time splashed across news sections of daily papers. Gabapentin (Neurontin): How it's Used for Depression and Anxiety. Medically reviewed by Denise Griswold, MSc, LCAS. October 24, 2018. 146. There are several drugs that may be prescribed for anxiety that were not developed originally for anxiety treatment. One such drug is Neurontin. Neurontin - also known as Gabapentin - is a drug that is sometimes prescribed to those who experience anxiety. I started taking 100 milligrams 3x day for anxiety 2 weeks ago. Then, just a couple days ago he bumped it up to 200 milligrams 3x day. I was on 200 milligrams for one day and then the very next day he bumped it up to 300 milligrams 3x day. How Long Does It Usually Take for Gabapentin to Work? Some people see improvement in their antigenic and/or anti-depressant symptoms about a week after starting treatment. Others need about a month before they see significant improvement. Gabapentin - How long does it take to start feeling an effect? Updated 7 Aug 2016 • 2 answers How long before 4mg of Abilify will start to work for BiPolar depression? How long does Gabapentin (Neurontin) take to work? Do you have experience with gabapentin for anxiety? How would you describe what a 100-200 mg gabapentin feels like to you?.