Chemotherapy-induced nausea and vomiting (CINV) is a distressing side effect that affects many patients undergoing emetogenic chemotherapy, despite the use of antiemetic medications. The purpose of this trial was to evaluate the efficacy and safety of gabapentin for the prevention of CINV during the first cycle of treatment in patients receiving moderately or highly emetogenic chemotherapy.

Eighty chemotherapy-naive patients, scheduled to receive moderately and highly emetogenic chemotherapy, were enrolled in this randomised, double-blind, placebo-controlled clinical trial. All patients received intravenous ondansetron 8 mg, dexamethasone 10 mg and ranitidine 50 mg before chemotherapy on day 1 and oral dexamethasone 4 mg twice a day on days 2 and 3. Patients were randomly assigned to take gabapentin 300 mg or placebo on the following schedule: 5 and 4 days before chemotherapy once daily, 3 and 2 days before chemotherapy twice daily, 1 day before to 5 days after chemotherapy thrice daily. The primary endpoint was complete overall protection from both vomiting and nausea over the course of the entire study (day 1 through day 5), and complete protection during the delayed period (24–120 h after chemotherapy).

The proportion of patients achieving complete response improved from 40% to 62.5%, (p = 0.04) when comparing the control group and the gabapentin group, respectively. In the subset of patients who achieved complete control in the acute phase, the percentage of patients who achieved delayed complete control was higher in the gabapentin group (89.3 × 60.7%, p = 0.01). Adverse events did not significantly differ between study arms.

Gabapentin is a low-cost strategy to improve complete control of CINV, specially delayed CINV control.