Four RCTs (n=755) were included in the review. For all comparisons, outcomes were statistically homogeneous.
Six weeks continuous abstinence: PQNP appeared to increased abstinence both alone (two studies, OR 1.91 (95% CI: 1.16, 3.14), p=0.011) and in combination with mecamylamine (two studies, OR 2.07 (95% CI: 1.04, 4.10), p=0.037). Both subgroups combined gave an overall OR of 1.96 (95% CI: 1.31, 2.93), p=0.001.
Six months continuous abstinence: PQNP appeared to increased abstinence both alone (two studies, OR 2.20 (95% CI: 1.39, 3.48), p=0.001) and in combination with mecamylamine (two studies, OR 2.08 (95% CI: 0.96, 4.50), p=0.065).
Both subgroups combined gave an overall OR of 2.17 (95% CI: 1.46, 3.22), p<0.001.
Sensitivity analysis indicated that no single study was responsible for the observed differences.