Hmm, I tend to not respond to anything that raises GABA, but if my insurance baclofen it's worth a shot. What sort of side effects are there and would I gain a tolerance to it if I took it every night?
I took it for about a year and a half, and did gradually increase my dose (from 10mg to 20mg nightly), I'm not sure if this was tolerance or if the lower dose helped some and I was being very cautious about increasing. My increase to 20mg coincided with my period of most consistent improvement - at least according to my activity levels (higher, fewer crashes) and symptom levels (lower). This could have just been a coincidence, something else going on, but it's possible I just found a better dose for getting more restorative sleep. I do feel like I could have upped my dose again after about 6 months at 20mg, though I didn't and didn't crash, so this could be some slow tolerance building. But unlike Heaps, I don't seem to develop tolerances very quickly, so YMMV.
As for side effects, it makes me a bit drowsy when I'd take it, but nothing dramatic, and I'd still need something for sleep initiation. Usually I would take half my dose about 1-1.5 hours before bed, and the second half with my sleep initiator (ambien in my case) when I went to bed. I did find that adding the baclofen, and this particular dosing pattern, allowed me to decrease my dosage of ambien (initiator). I didn't notice any day time drowsiness associated with it the next morning, though I might not have noticed if it was mild or subtle. Unlike the antihistamine doxylamine (which is my second string, baby safe, sleep maintenance med) which when I took a 'normal' dose left me seriously groggy for about 20 hours. 1/4 of the doxylamine does help me but I miss the baclofen, it worked much better for me.
Also I stopped taking the baclofen because there are some risks in pregnancy, but, other than an increase in nighttime wakefulness and muscle pain (the symptoms it helped me with), I didn't suffer any withdrawal type side effects. I think this is fairly normal, and might be something to consider if you're trying to decide between it and something with more 'strings' attached (like benzo's).