Participants were maintained on the assigned dose until Week 11, and then were titrated off active medication by substituting one placebo capsule for one capsule of active medication per day, in the reverse order of the initial dose titration, until all subjects received only placebo by the end of Week 12. Participants returned their blister cards at each weekly study visit for drug accountability and compliance review. Correct drug assignment was verified retrospectively by determining gabapentin concentration in plasma samples obtained at Week 2 and frozen for post-study analysis by gas chromatography/mass spectrometry.
