I've prescribed it VVV. It was devised as an anti-epileptic, but the action it has on nerve cells (rempy now racking brain - on mat leave at moment - it interferes with the sodium channels thus affecting the transmission of the electical impulses along nerve cells) it also is effective in chronic pain.
It does have, as most drugs, a rather long list of side effects some of which are terrifying. In general though, the message I get from the chronic pain consultants is that it is well tolerated by most people.
I cant advise about interactions with your anti-depressants, but would think that your consultant would have taken that into consideration.
Amitryptilline is sedating for a while (fortnight or so), and can be with each dose increase. It also has some grim side effects, although these are less when it is used for pain rather than depression, as the doses are much less when it is prescribed for pain.
Devil and deep blue for you it sounds like. I would not fancy facet injections myself, so would be giving the pills a go.