Objective: To identify and describe the response profile of pregabalin on the qualities of pain associated with peripheral neuropathy.

Methods: A post hoc analysis to examine the effects of pregabalin on pain quality in patients with moderate-to-severe peripheral neuropathic pain was performed using data from an enriched enrollment randomized withdrawal proof-of-concept study. Patients rated the quality of their pain experience using the Pain Quality Assessment Scale (PQAS) at baseline, after a 12-day titration period, after a 9-day maintenance period, and after a 19-day randomized withdrawal period. Pretitration to posttitration and prewithdrawal to postwithdrawal changes in PQAS paroxysmal, surface, and deep pain scale scores were examined.

Results: PQAS data were available for 99 of the 104 participants who entered all phases of the study. There were significant (P<0.006, Bonferroni adjusted for multiple tests) improvements pretitration to posttitration in all 3 PQAS subscales, with a greater effect on paroxysmal and deep pain than on surface pain. During the withdrawal phase, pregabalin was significantly (P<0.006) more effective than placebo for improvements in paroxysmal and surface pain only, although the pregabalin group continued to show numerical improvement in deep pain relative to placebo.

Discussion: Pregabalin had a greater effect on PQAS-assessed paroxysmal pain than on surface or deep pain in patients with peripheral neuropathy. The findings corroborate previous research demonstrating differential effects of analgesic drugs across pain qualities, further emphasizing the need to assess individual pain qualities in addition to overall pain intensity.