Nicotine for postoperative analgesia: a systematic review and meta-analysis.

BACKGROUND: The perioperative adminstration of nicotine has been investigated as an analgesic adjunct and a possible modality to prevent postoperative nausea and vomiting (PONV). We performed this systematic review to assess the impact of perioperative administration of nicotine on postoperative pain and PONV.

METHODS: A literature search of MEDLINE, CENTRAL, EMBASE, and CINAHL was done for randomized controlled trials that investigated the effects of nicotine compared with placebo regarding postoperative pain and/or PONV in patients undergoing surgery under general anesthesia. A random effects model was used for analysis. The primary end points were cumulative analgesic consumption and pain scores at 24 hours after surgery.

RESULTS: Nine studies (662 patients) were included. Nicotine was administered as a transdermal patch in 6 studies and as a nasal spray in 3. Four studies recruited only women while 7 recruited only nonsmokers. Perioperative nicotine administration was associated with a reduction in cumulative opioid consumption at 24 hours compared with control (mean difference = -4.85 mg morphine equivalents, 95% confidence interval [CI], = -9.40 to -0.30, P = 0.04). Pain scores were neither clinically nor statistically reduced. Nicotine was associated with a significantly higher incidence of postoperative nausea (relative risk = 1.26, 95% CI, = 1.05 to 1.52) and need for rescue antiemetics (relative risk = 1.54, 95% CI, = 1.37 to 1.74) during the first postoperative hour and significantly higher postoperative nausea at 24 hours (relative risk = 1.14, 95% CI, = 1.02 to 1.28). The 24 hours opioid sparing was only seen in nonsmokers. When excluding 1 study with high risk of bias, nicotine was still associated with more postoperative nausea at 24 hours (relative risk = 1.15, 95% CI, = 1.05 to 1.25).

CONCLUSIONS: This systematic review suggests that perioperative nicotine administration was associated with a statistically significant reduction in cumulative opioid consumption at 24 hours and a statistically insignificant reduction in pain scores at 24 hours. Perioperative nicotine was also associated with an increased incidence of postoperative nausea in patients undergoing surgery under general anesthesia. The opioid-sparing effect seemed to be limited to nonsmokers. Current data do not support a role for nicotine in perioperative analgesia.