Gabapentin attenuates the pressor response to direct laryngoscopy and tracheal intubation

Background. Laryngoscopy and tracheal intubation increase blood pressure and heart rate (HR). The aim of the present study was to investigate the effect of gabapentin when given before operation on the haemodynamic responses to laryngoscopy and intubation. Methods. Forty-six patients undergoing abdominal hysterectomy for benign disease were randomly allocated to receive gabapentin 1600 mg or placebo capsules at 6 hourly intervals starting the day (noon) before surgery. Anaesthesia was induced with propofol and cis-atracurium. Systolic, diastolic arterial blood pressures (SAP, DAP) and heart rate (HR) were recorded before and after the anaesthetic and 0, 1, 3, 5 and 10 min after tracheal intubation. Results. SAP was significantly lower in the gabapentin vs the control group 0, 1, 3, 5 and 10 min after intubation [128 (27) vs 165 (41), P=0.001, 121 (14) vs 148 (29), P=0.0001, 115 (13) vs 134 (24), P=0.002, 111 (12) vs 126 (19), P=0.004 and 108 (12) vs 124 (17), P=0.001 respectively]. DAP also was lower in the gabapentin group 0, 1, 3, and 10 min after intubation [81 (18) vs 104 (19), P=0.0001, 77 (9) vs 91 (16), P=0.001, 71 (10) vs 84 (13), P=0.001 and 67 (10) vs 79 (12), P=0.004]. HR did not differ between the two groups at any time [82 (11) vs 83 (15), 79 (10) vs 80 (12), 86 (17) vs 92 (10), 82 (11) vs 88 (10), 81 (12) vs 81 (11), 77 (13) vs 79 (13), and 75 (15) vs 78 (12)]. Conclusion. Gabapentin, under the present study design attenuates the pressor response but not the tachycardia associated with laryngoscopy and tracheal intubation.