Efficacy and safety of pregabalin in patients with diabetic peripheral neuropathy or postherpetic neuralgia: Open-label, non-comparative, flexible-dose study.

We assessed the efficacy and safety of a flexible-dose pregabalin regimen in patients with diabetic peripheral neuropathy (DPN) or postherpetic neuralgia (PHN) under clinical practice conditions. Further, the trial investigated the correlation of unspecific measures of change (patient and physician global impression of change, PGIC and CGIC) and specific measures of morbidity. The primary outcomes of this prospective, open-label, non-controlled study were the correlation between global status (PGIC and CGIC) and changes in pain, sleep, and anxiety scores as assessed on numerical or visual rating scales. A total of 217 outpatients were included in 53 centres. The most frequently used dosing regimen involved a starting dose of 150mg/d and dose escalation to 300mg/d after one week (mean: 301mg/d, administered in two doses). The significant changes on pain, sleep and anxiety scales (-40%, -43%, -42%) between baseline and study end after 4-week pregabalin treatment were paralleled by the changes in ratings in both the PGIC and CGIC. The correlation with both PGIC and CGIC was 0.60 for pain, 0.51 for sleep and 0.20 or 0.13 for the correlation of anxiety with PGIC and CGIC, respectively. All correlations with exception of the pair CGIC/anxiety reached statistical significance. In conclusion, pregabalin in a flexible-dose regimen improved pain, sleep, anxiety and general state, and was well tolerated. The efficacy and safety profile of pregabalin was consistent with the data from the controlled clinical trials. The PGIC and CGIC and the specific pain and sleep scores, but not the anxiety score were generally well correlated but not synonymous.