Double-blind comparison of granisetron, promethazine, or a combination of both for the prevention of postoperative nausea and vomiting in females undergoing outpatient laparoscopies.

Purpose: Postoperative nausea and vomiting (PONV) and postdischarge nausea and vomiting (PDNV) are common problems after surgery. Prophylactic combination antiemetic therapy is recommended for patients at high risk for developing PONV and PDNV. Granisetron, a serotonin antagonist, is an effective antiemetic that is devoid of sedative side effect. Although promethazine is effective, commonly used doses are associated with sedation. This study investigates the combination of low doses of granisetron and promethazine for the prevention of PONV.

Methods: Women undergoing ambulatory gynecological laparoscopy were enrolled. A standard general anesthetic regimen was prescribed. Fifteen minutes before the expected end of surgery, the patients were randomly assigned to receive granisetron 0.1 mg iv, promethazine 6.25 mg iv, or a combination of the two drugs. Prophylaxis with oral promethazine 12.5 mg, granisetron 1 mg, or both was started in the respective groups 12 hr after the end of surgery and continued every 12 hr until postoperative day 3 (a total of five oral doses). The following outcomes were recorded: total response rate (defined as no vomiting, no more than mild nausea, and no use of rescue antiemetic); incidence of nausea, vomiting, and use of rescue antiemetics; severity of nausea; patient activity level; and patient satisfaction with PONV management.

Results: Patients in the combination group had a higher total response rate at 6, 24, 48, and 72 hr after surgery compared with those who received promethazine alone (at 24 hr, Combination 69.6%, Promethazine 36.2%, Granisetron 53.3%; P = 0.0079). The maximum nausea scores were also lower in the combination group at 6, 24, 48, and 72 hr (Combination 1.7 +/- 2.2, Promethazine 4.0 +/- 3.6, Granisetron 3.1 +/- 3.2 at 24 hr; P < 0.05). There was no difference in the sedation scores, incidence of drowsiness, patient activity level, and satisfaction with PONV management.

Conclusions: Low-dose granisetron and promethazine combination was more effective in reducing PONV and PDNV than promethazine monotherapy. The combination also reduced the severity of nausea.