My vet actually hands out gabapentin as part of their Calm Kitty visit pack. It's very safe and mild. If you have a fussy cat, you get a cute little bag with a couple of pills, some catnip, and a Feliway wipe. I get my sassy old cat a little high when she has to go in for a blood draw. She'll get a little tipsy and then come home and sleep so well that she snores.