I don't know about combining them; I know that inositol by itself worked well for me when coming off Effexor. I wish I had known about it before I started the meds.
I took the powder form, 3x/day for a total of 6 grams; all with grapefruit juice to increase absorption. If I was to do it again, I'd probably stack in a couple hundred mgs of 5HTP with it.
Search through the archives for some of GaryWary's old posts; he knew quite a bit about inositol.