title: Gabapentin premedication decreases the hemodynamic response to skull pin insertion in patients undergoing craniotomy.
abstract: BACKGROUND
  In patients undergoing craniotomy, skull pin insertion produces significant increases in heart rate (HR) and blood pressure. We investigated whether premedication with gabapentin would prevent or attenuate this increase.
  
  
  METHODS
  Forty-seven ASA I and II patients, 18 to 60 years, undergoing elective craniotomy for intracranial tumor surgery were recruited prospectively and randomly divided into 3 groups; L (oral placebo plus 2% lidocaine infiltration at pin sites; n=12), G (oral gabapentin 900 mg plus normal saline infiltration; n=21) and GL (oral gabapentin 900 mg plus 2% lidocaine infiltration; n=14). The oral medications were administered 2 hours before induction of anesthesia. Measurements were made at preinduction baseline, before skull pin insertion and at every 1 minute from pin insertion till end of 10 minutes.
  
  
  RESULTS
  Forty-three patients completed the study (L, n=11; G, n=20; GL, n=12). Premedication with gabapentin significantly attenuated the rise in systolic (SBP) and mean arterial pressure (MAP) after pin insertion when compared with placebo (for SBP, P<0.001 at 1 and 2 min and <0.05 at 3 to 5 min between L and G; P<0.001 at 1 to 4 min and <0.05 at 5 min between L and GL; for MAP, P<0.05 at 1 min, <0.001 at 2 min and <0.05 at 3 to 4 min between L and G; P<0.001 at 1 to 2 min and <0.05 at 3 to 5 min between L and GL). HR responses were also attenuated in patients premedicated with gabapentin; however, the responses were more variable in group G (P=0.03 between L and G at 4 min after pin insertion) as compared with group GL (P<0.05 at 1 min, <0.001 at 2 min and <0.05 at 3 to 10 min between L and GL).
  
  
  CONCLUSIONS
  In conclusion, 900 mg of gabapentin, administered orally 2 hours before induction of anesthesia along with lidocaine scalp infiltration abolished the hemodynamic response after skull pin insertion. Premedication with gabapentin alone significantly attenuated the SBP and MAP; however, HR responses were more variable. A larger trial is required to corroborate the findings of the study before clinical recommendations would be warranted.
authors.affiliation: Department of Anesthesiology, Sree Chitra Tirunal Institute for Medical Sciences & Technology, Trivandrum, Kerala, India. misrasatyajeet@gmail.com
authors.forename: Satyajeet
authors.initials: S
authors.lastname: Misra
authors.forename: Thomas
authors.initials: T
authors.lastname: Koshy
authors.forename: Koniparambil Pappu
authors.initials: KP
authors.lastname: Unnikrishnan
authors.forename: Puthuvassery Raman
authors.initials: PR
authors.lastname: Suneel
authors.forename: Nilay
authors.initials: N
authors.lastname: Chatterjee
mesh_terms: D000293:Adolescent; D000328:Adult; D000588:Amines / Q000627:therapeutic use*; D000768:Anesthesia, General; D018685:Anesthetics, Inhalation; D000779:Anesthetics, Local / Q000627:therapeutic use; D001794:Blood Pressure / Q000187:drug effects; D001858:Bone Nails; D001932:Brain Neoplasms / Q000601:surgery; D003399:Craniotomy; D003509:Cyclohexanecarboxylic Acids / Q000627:therapeutic use*; D018691:Excitatory Amino Acid Antagonists / Q000627:therapeutic use*; D005260:Female; D000077206:Gabapentin; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D007432:Intraoperative Period; D008012:Lidocaine / Q000627:therapeutic use; D008297:Male; D008738:Methyl Ethers; D008875:Middle Aged; D011229:Preanesthetic Medication; D011446:Prospective Studies; D012129:Respiratory Function Tests; D000077149:Sevoflurane; D012886:Skull / Q000601:surgery*; D055815:Young Adult; D005680:gamma-Aminobutyric Acid / Q000627:therapeutic use*
chemical_list: D000588:Amines; D018685:Anesthetics, Inhalation; D000779:Anesthetics, Local; D003509:Cyclohexanecarboxylic Acids; D018691:Excitatory Amino Acid Antagonists; D008738:Methyl Ethers; D000077149:Sevoflurane; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin; D008012:Lidocaine