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, gabapentin also showed significant linear decreases in the average number of days of heavy drinking per week (t=13.12, p<0.001; Figure 3a; 900mg: −1.76 [95% CI, −2.2 to −1.3], t=−7.22, p<0.001; 1800mg: −2.02 [95% CI, −2.5 to −1.5], t=−8.14, p<0.001) and the number of drinks consumed per week (t=5.32, p<0.001; Figure 3b; 900mg: −2.16 [95% CI, −5.3 to 1.0], t=−1.30, p=0.195; 1800mg: −6.66 [95% CI, −9.8 to −3.5, t=−4.13, p<0.001). Gabapentin also had a significant linear dose effect on reduction in log transformed GGT values (F=4.41, df=2, p=0.015). On an exploratory basis, drinking outcomes were evaluated for the 65 participants who completed both the 12-week trial and the Week 24 follow-up visit. Significant linear dose effects were sustained at Week 24 for rate of complete abstinence (χ2=4.73, df=1, p=0.022), number of drinks per week (t=2.01, p=0.044), and number of heavy drinking days per week (t=3.09, p=0.002), with a non-significant trend for rate of no heavy drinking (χ2=6.43, df=1, p=0.058).
