Pregabalin long-term treatment and assessment of discontinuation in patients with generalized anxiety disorder

Discontinuation effects following cessation of 12 and 24 wk of pregabalin treatment for generalized anxiety disorder (GAD) were evaluated in a placebo- and lorazepam-controlled, randomized, double-blind, multicentre trial conducted in 16 countries. The study design consisted of two 12-wk treatment periods (periods 1 and 2), each followed by a 1-wk taper and two post-discontinuation assessments, one immediately following the taper and one 1-wk post-taper. Patients were assigned to receive an initially flexible dose of pregabalin 450-600mg/d, pregabalin 150-300mg/d, or lorazepam 3-4mg/d for 6 wk; responders continued fixed-dose therapy for 6 additional weeks. Patients entering period 2 continued on the same fixed dose or switched to placebo. Discontinuation effects were evaluated with the Physician Withdrawal Checklist (PWC) and reported discontinuation-emergent signs and symptoms. Rebound anxiety was measured with the Hamilton Anxiety Rating Scale. GAD symptoms improved with all treatments and improvements were maintained over 12 and 24 wk. Low levels of discontinuation symptoms were evident in all treatment groups. For patients who received active treatment during both periods, mean (95% confidence interval) increases on the PWC from last visit on active treatment to the second post-discontinuation assessment were: pregabalin 450-600mg/d: 2.8 (1.6-3.9), pregabalin 150-300mg/d: 1.7 (0.7-2.8), lorazepam 3-4mg/d: 2.2 (1.0-3.5). Rates of rebound anxiety were also low at both 12 and 24 wk (0-6%). This suggests that risk of discontinuation symptoms and rebound anxiety are low for pregabalin after 12 and 24 wk of treatment.