Five RCTs (n=2,195) were included in the review.
All of the included studies received the highest score on the Jadad scale.
Compared with placebo, alvimopan 12 mg was associated with a significant improvement of GI-3 (HR 1.30, 95% CI: 1.16, 1.45, p<0.001; based on 4 studies), GI-2 (HR 1.61, 95% CI: 1.26, 2.05, p<0.001; 4 studies), time to discharge (HR 1.26, 95% CI: 1.13, 1.40, p<0.001; 4 studies), time to bowel motion (HR 1.74, 95% CI: 1.29, 2.35, p<0.001; 3 studies), and time to first solid food tolerated (HR 1.14, 95% CI: 1.01, 1.30, p=0.04; 3 studies).
Alvimopan 6 mg also significantly improved these outcomes; the effects of both doses were comparable without a clear dose-response curve. There was evidence of significant statistical heterogeneity for G-2 in studies evaluating the 12-mg alvimopan regimen (p=0.01, I-squared 73.7%), and for both G-3 (p=0.01, I-squared 73%) and G-2 (p=0.03, I-squared 65.7%) in studies evaluating the 6-mg alvimopan regimen.
The use of opioid drugs and the visual analogue scores were similar between placebo and alvimopan groups in the 5 trials that reported on these outcomes. Patients receiving alvimopan required reinsertion of the nasogastric tube after surgery less often in 2 out of 3 studies reporting this outcome. There was no difference in adverse events between the alvimopan and placebo groups.
The authors stated that the funnel plot suggested only minimal publication bias.