The effect of pregabalin on preoperative anxiety and sedation levels: A dose-ranging study

BACKGROUND:: Pregabalin is a gabapentinoid compound, which has been alleged to possess anxiolytic, analgesic, and anticonvulsant properties. We hypothesized that premedication with oral pregabalin would produce dose-related reductions in acute (state) anxiety and increases in sedation (sleepiness) before induction of general anesthesia. A secondary objective was to determine if premedication with pregabalin would reduce postoperative pain. METHODS:: One hundred eight ASA I-III outpatients undergoing elective surgery were randomly assigned to one of the four premedication treatment groups: 1) control group received placebo capsules, 2) pregabalin 75 group received pregabalin 75 mg, po, 3) pregabalin 150 group received pregabalin 150 mg, po, and 4) pregabalin 300 group received pregabalin 300 mg, po. The effects of the study drug on the patients' level of anxiety, sedation, and pain were assessed at baseline (immediately before study drug administration), at 30 and 60 min after drug administration, and immediately before induction of anesthesia, as well as at 30-min intervals in the postanesthesia care unit (PACU) using standardized 11-point verbal rating scales, with 0 = none to 10 = maximal effect. The need for postoperative opioid analgesic medication, incidence of nausea and vomiting, requirement for rescue antiemetics, and times to discharge from the PACU and hospital, as well as the patients' quality of recovery scores, and late recovery outcomes (e.g., resumption of dietary intake and recovery of bowel function) were assessed at a 7-day follow-up interview. RESULTS:: Demographic characteristics, times between study drug administration to anesthetic induction, type of surgical procedures, duration of anesthesia, PACU and hospital discharge time, as well as the requirement for fentanyl in the PACU, did not differ among the four study groups. Anxiety levels remained unchanged during the preoperative evaluation period, and did not differ among the four study groups. Sedation scores were significantly higher in the pregabalin 300 group at the preinduction assessment interval and at 90 and 120 min after surgery compared with the control group (5 ± 3 vs 3 ± 2, 7 ± 4 vs 5 ± 3, 8 ± 4 vs 4 ± 4, respectively, P < 0.05). CONCLUSION:: Preoperative pregabalin administration (75-300 mg po) increased perioperative sedation in a dose-related fashion, but failed to reduce preoperative state anxiety, postoperative pain, or to improve the recovery process after minor elective surgery procedures.