Cappuzzo baseline and at randomization. The primary efﬁcacy point was the mean of the last 7 daily pain scores on the 11-point pain scale. Endpoint mean pain scores were signiﬁcantly reduced for both PGB 150 mg/day and PGB 300 mg/day groups compared to placebo. Signiﬁcant improvement in pain was noted as early as week 1 and maintained throughout the study. There appeared to be some additional pain relief from the 300 mg/day dose versus the 150 mg/day dose per the endpoint mean pain scores reported by the patients in each PGB group. Those receiving 300 mg/day of PGB reported a mean pain score of 4.76 as compared to a 5.14 mean pain score in those receiving 150 mg/day; patients on placebo reported a mean pain score of 6.33 (p = 0.0001 and 0.0002 for 300 mg/day and 150 mg/day versus placebo, respectively). A signiﬁcantly larger proportion of patients in both treatment groups obtained a 50% reduction in mean pain score from baseline to study end point (26% on 150 mg/day [p = 0.006] and 28% on 300 mg/day [p = 0.003] versus 10% on placebo). As with the previous trial, daily sleep interference scores were recorded by study subjects in diaries using an 11-point numerical rating scale. Both doses of PGB signiﬁcantly reduced weekly mean sleep interfer- ence scores versus placebo (3.13 for those on 150 mg/day [p = 0.0003], 2.81 for those on 300 mg/day [p = 0.0001] and 4.24 for those on placebo).7 A 13-week trial in 370 patients with PHN of 3 months’ duration following the healing of HZ lesions was conducted to evaluate the efﬁcacy of twice daily PGB therapy.18 Stable medication regimens (deﬁned as medications taken 30 days prior to study entry) of non-opioid analgesics (eg, paracetamol, noramidopyrine), opioids, anti-inﬂammatory medications, and antidepressants were allowed during the trial. Prohibited medications included long-acting benzodiazepines, skeletal muscle relaxants, steroids, and anticonvulsants, among others; these had to be discontinued at least 7 days prior to study entry. Patients with a CrCl 30 mL/min were excluded from the trial. Patients were randomized to 1 of 4 treatment groups: placebo (n = 93), 150 mg/day (n = 87), 300 mg/day (n = 98), and 600 mg/day (n = 90). Doses were divided twice daily. Because a 50% reduction in CrCl is expected to result in a doubling of PGB exposure, patients in the 600 mg/day group were stratiﬁed based on CrCl: patients with CrCl 60 mL/min received 600 mg/day, and those patients with CrCl 30 and 60 mL/min received 300 mg/day, a dosage believed to provide equivalent exposure to 600 mg/day in patients with CrCl 60 mL/min, based on pharmacokinetic studies.18,26 Mean age of the patients was 70.7 years, with 82% of patients over 65 years of age, and the mean duration of PHN was 20 40.7 months. Patients were required to have an average daily pain score of at least 4 on an 11-point numerical rating scale (0 = no pain; 10 = worst possible pain) on at least 4 days during the 7-day baseline period. Additionally, patients were required to have a score of 40 mm on a 100 mm VAS at baseline and at randomization. Primary outcome measure was the endpoint mean pain score from the last 7 days of the patients’ daily pain diaries. As with the previous two trials discussed, this study assessed related sleep interference due to pain as a secondary outcome. Daily sleep interference scores were again recorded by study subjects in diaries using an 11-point numerical rating scale. At endpoint, PGB demonstrated significant dose-dependent improvement in mean pain scores and signiﬁ- cant improvement in mean sleep interference versus placebo. Mean pain scores decreased in a dose-dependent fashion as follows: PGB 150 mg/day was 5.26, PGB 300 mg/day 5.07, PGB 600 mg/day 4.35, and these were all signiﬁcantly lower versus the placebo mean pain score of 6.14 (p = 0.0077, 0.0008, and 0.0001, for PGB 150, 300, and 600 mg/day, respectively). Mean sleep interference scores showed a similar dose- dependent pattern: PGB 150 mg/day 3.07, PGB 300 mg/day 2.84, and PGB 600 mg/day 2.17, and these were all signiﬁcantly lower than the placebo score of 4.10 (p = 0.0007, 0.0001, and 0.0001, for PGB 150, 300, and 600 mg/day, respectively). These improvements in pain and sleep were seen as early as Week 1 of treatment. Additionally, signiﬁcantly more patients in the PGB-treated groups demonstrated a 50% reduction in pain from baseline than those on placebo (26.4%, 26.5%, 37.5%, and 7.5% in the PGB 150 mg/day, 300 mg/day, 300/600 mg/day, and placebo groups, respectively; p = 0.001 for each PGB group versus placebo). The number needed to treat (NNT) based on those with 50% reduction in pain from baseline for all PGB dosages combined was 4.4.18 A 12-week trial examined the efﬁcacy and tolerability of ﬂexible- and ﬁxed-dose regimens of PGB versus placebo in patients with PHN and painful DPN.25 PHN patients had pain present for 3 months after the healing of the HZ rash. Unlike the previously discussed trials, patients who had previously taken gabapentin were permitted in the trial, regardless of dose or duration of exposure. Use of SSRIs, aspirin, short-acting benzodiazepines (for insomnia), and paracetamol was permitted during the trial. Medications that were prohibited include drugs commonly used to treat neuropathic pain (eg, skeletal muscle relaxants, capsaicin cream, opioids, benzodiazepines), anticonvulsants, non-SSRI antidepressants, and drugs that may cause retinotoxicity (eg, hydroxychloroquine, thioridazine). Prohibited drugs had to be discontinued at least 7 days prior to the baseline visit. Clinical Interventions in Aging 2009:4