I learned to stagger my gabapentin prescription by watching Bluelight. No, really. Had a script for like three years now, and it IS the way to enjoy this truly great (for some, alcoholics seem to really like it, case in point) medication. Also, try not to abuse this one (hard to anyway)--she's your very slow best bud who shows up four hours late, you'll never party or have drunken sex, but she'll say the just the right thing to leave you feeling OK. Gabapentin has eliminated any need for booze with me, and I wish more folks would sing that).
It's not your blood, or even your liver, that effects the concentration, but your guts. There's a specific transporter that moves the drug into your bloodstream, and it gets overwhelmed around the therapeutic dose. You could eat a dozen, and most of it will move to your poop chute before it can be absorbed.
So before the mods banish you to the search engines, I'll share: simplest for me is 600mg at T-4 hours, -3.5, and like -1, T being dinner out with extended family or whatever your anxiety triggers are. Best to keep it at that, but sometimes you'll really want to ride the "buzz" out if you start early, and you can reserve a #4 or #5 at least two hours apart. Yes, of course I've chewed one every half hour all day long. But like I said, she just won't have sex with you, stop asking and enjoy this actually amazing evening. The extra doses (I get 3x600/day/month) go toward forced abstinence to help avoid tolerance.
Esp. for day-long horrors of sober living you want to keep your tolerance low and your pills plenty. NB: this schedule at first will add extra time to any pop math quizzes, and the mood shift IS apparent to others, so be prepared for accusations of using if you have a history (you'll walk a straight line but be comfortable and actually TALK to people, just like when you did DRUGS!!!).
Also, get a doctor to agree to this if you do rehab--Nurse Ratched will be the one administering them according to the label.