Gabapentin had a significant linear dose effect in increasing the rates of complete abstinence (χ2=4.19, df=1, p=0.04) and no heavy drinking (χ2=5.39, df=1, p=0.02) over the 12-week course of treatment, relative to placebo (Figure 2). The rate of sustained 12-week abstinence was 4.1% (95% CI, 1.1 to 13.7) in the placebo group, 11.1% (95% CI, 5.2 to 22.2) in the 900 mg group and 17.0% (95% CI, 8.9 to 30.1) in the 1800 mg group. Gabapentin 1800mg had the greatest treatment effect, with a NNT of 8 (95% CI, 6 to ∞) and an OR=4.8 (95% CI, 0.9 to 35), indicating a large effect size for abstinence.37 The rate of no heavy drinking was 22.5% (95% CI, 13.6 to 37.2) in the placebo group, 29.6% (95% CI, 19.1 to 42.8) in the 900 mg group, and 44.7% (95% CI, 31.4 to 58.8) in the 1800 mg group. The gabapentin 1800mg group had a NNT of 5 (95% CI, 3 to 78) and OR=2.8 (95% CI, 1.1 to 7.5), indicating a medium effect size for no heavy drinking.37 Compared to placebo,
