Pregabalin beneficial effects on sleep quality or health-related quality of life are poorly correlated with reduction on pain intensity after an eight-week treatment course

Abstract: Pregabalin (PGB) is an anticonvulsivant drug that binds to α2-δ subunit of the N-type voltagedependent Ca-channel (VDCC). VDCC-containing subunits appear to be involved in presynaptic regulation of neurotransmitter release. It has been shown that PGB is capable of inhibiting glutamate, noradrenaline, acetylcholine and substance P release at several different central nervous system locations including the neocortex, the amygdala, the hippocampus, the striatum, the spinal cord, the cerebellum and the habenula. PGB is approved by the United States Food and Drug Administration for the treatment of painful diabetic peripheral neuropathy, fibromyalgia, and postherpetic neuralgia, and as adjunctive therapy in adults with partial-onset seizure disorder. In Europe, pregabalin is also approved for neuropathic pain and generalized anxiety disorder. PGB effects on sleep quality and Health-related Quality of Life (HRQoL) have been studied in many clinical trials. For example, a recent meta-analysis has shown that PGB 150-600 mg/day significantly improved pain-related sleep interference in patients with neuropathic pain. HRQoL was also improved by PGB. It has been suggested that improvements on sleep or HRQoL may be correlated to PGB analgesic effects, but the magnitude of such correlation remains unknown. Therefore, we conducted the present study aiming at further exploring the correlation between changes in pain intensity, sleep quality and HRQoL after a PGB 8-week treatment course