Is lyrica (pregabalin) supposed to improve the aspect of pain or the sleep in fibromyalgia patient?

Theoretically, both.: Lyrica (pregabalin) works on the GABA-nergic system (the primary inhibitory neurotransmitter in the human brain). Pain stimulates the neurons fire at a higher rate than "normal". Lyrica (pregabalin) is supposed to decrease the rate of firing at the neural synapse (thereby reducing the perception of pain). Also, Lyrica (pregabalin) increases slow wave sleep and has some very interesting effects on sleep architecture. Hope that helps!

Both: The dose of Lyrica (pregabalin) is highly variable. The limiting factor for daytime use is its tendency to put people to sleep. I recommend taking enough during the day to alleviate the nerve pain, and enough at night to get a good night's sleep. Lyrica (pregabalin), like its cousin Gabapentin, is a great sleep-inducer. It's a natural sleep, unlike the benzos. I have one patient on 225 mg 3 times daily. Doing well.