Gabapentin presentation

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  • Spinal anaesthesia with bupivacaine and fentanyl, COX-2 antagonist given routinely, paracetamol and steroids.
  • Gabapentin presentation

    1. 1. Perioperative use of gabapentin for orthopaedic surgery
    2. 2. Research  Knowledge Network (formerly e-library Scotland) title searches  “gabapentin orthopaedic surgery”  “gabapentin orthopedic surgery” and  “gabapentin surgery”  Also, OVID search (24 articles with “gabapentin” and “surgery” in title)  Articles not in English rejected (rightly or wrongly)  No useful additional articles found when using “orthopedic” for “orthopaedic” except for an Editorial note retracting multimodal analgesia articles written by Reuben (admitted to making most of his work up)
    3. 3. Questions  1. What is the evidence for Gabapentin reducing acute pain following orthopaedic surgery?  2. What is the evidence for Gabapentin reducing chronic pain following orthopaedic surgery?  3. What doses of Gabapentin are recommended for peri-operative use?
    4. 4. Acute Pain  Gabapentin: a multimodal perioperative drug? (Review article, BJA 2007)  Meta-analysis in “Pain” (2006) reported: Three sub-groups – Single dose 1200mg preop Single dose <1200mg preop Multiple doses in periop period  Pain intensity significantly decreased at 6 and 24 hours in groups 1 and 2 (but not group 3).  24-hour opioid consumption significantly reduced in all 3 groups.  Overall, 27 studies on periop gabapentin identified in this article  7 ‘orthopaedic’ including spinal fusion/laminectomy, ‘major ortho surgery’ and arthroscopic procedures
    5. 5. Acute pain  (i). Preoperative gabapentin decreases anxiety and improves early functional recovery from knee surgery (Anesthesia Analgesia 2005)  One dose 1200mg oral gabapentin preop vs. control. 20/20 subjects  Gabapentin ‘reduced anxiety’ (visual analogue scoring), reduced VAS pain scores during intial hour of recovery (but not subsequently) and allowed patients to tolerate more passive/active knee flexion.
    6. 6. Acute pain  (ii). Effect of preemptive gabapentin on postoperative pain relief and morphine consumption following lumbar laminectomy and discectomy (Journal Neurosurgical Anesthesiology 2005)  Gabapentin 800mg (2 divided doses) or placebo preop. 30/30  No statistically significant findings
    7. 7. Acute pain  (iii). Effect of gabapentin on post-op pain [following major orthopaedic surgery] (The Pain Clinic 2005)  Unable to source reference but summary –  800mg or 1200mg preop. 30/15  No statistical difference in pain score reduction but opioid sparing
    8. 8. Acute pain  (iv). Analgesic effects of gabapentin after spinal surgery (Anesthesiology 2004)  1200mg 1 hour preop. vs. placebo. 25/25  Significantly lower pain scores (only up to postop 4 hours – NS at 24 hours)  Less vomiting and urinary retention in treatment group (p<0.05)
    9. 9. Acute pain  (v). A single preoperative dose of gabapentin (800mg) does not augment postop analgesia in patients given interscalene brachial plexus block for arthroscopic surgery (Anesthesia Analgesia 2006)  800mg 2 hours preop. 27/26  No augmentation of postop analgesia
    10. 10. Acute pain  (vi). Effect of oral gabapentin on postoperative epidural analgesia (BJA 2006)  1200mg 1-hour preop and then 1200mg on 1st and 2nd postop days (doses not divided). 20/20  Lower pain scores and better ‘patient satisfaction’. More dizziness
    11. 11. Acute pain  (vii). Premedication with gabapentin: the effect on tourniquet pain and quality of intravenous regional anaesthesia (Anesthesia Analgesia 2007)  1200mg 1 hour preop. 20/20  Decreased tourniquet-related pain and reduced pain scores in early postop period.
    12. 12. Acute pain  Additional articles not identified by BJA review:  (viii). Pre-emptive gabapentin significantly reduces postop pain and morphine demand following lower extremity orthopaedic surgery (Singapore Medical Journal 2007)  300mg 2 hours preop. 35/35  Significant decrease in postop pain and rescue analgesic requirements  Lower VAS scores at 2, 4, 12 and 24 hours
    13. 13. Acute pain  (ix). Adding Gabapentin to a multimodal regimen does not reduce acute pain, opioid consumption or chronic pain after total hip arthroplasty (Acta Anaesthesiology Scandinavia 2009)  3 groups: (P/P-39, G600/P-40, P/G600-38) Gaba 1-2 hours pre-op or Gaba in PACU  Regional anaesthesia used  Similar opioid consumption overall and no difference in pain scores at 12,24,36,48h  No difference found in sedation, N&V or dizziness either (unlike most other studies)  [No significant (p ‘>’ 0.05) difference in chronic
    14. 14. Which papers are joint replacement studies?  (1st study: Preop gabapentin decreases anxiety and improves early functional recovery from knee surgery = Ant. cruciate ligament surgery)  Effect of oral gabapentin on postop epidural analgesia (BJA 2006)  ‘Lower extremity surgical procedures’ ?which ops  Pre-emptive gabapentin significantly reduces postop pain and morphine demand following lower extremity orthopaedic surgery (Singapore Medical Journal 2007)  ‘Lower extremity orthopaedic surgery’ ?which ops  Adding Gabapentin to a multimodal regimen does not reduce acute pain, opioid consumption or chronic pain after hip arthroplasty (Acta Anaesthesiology Scandinavia 2009)
    15. 15. Chronic pain  From 2002 to 2006, 4 RCTs using perioperative gabapentin to prevent chronic pain after amputation, breast and abdominal surgery.  Post-amputation paper:  A randomized study of the effects of gabapentin on postamputation pain (Anesthesiology 2006)  Gabapentin started immediately after surgery (??) and continued for 30 days. Treatment started on postop day 1 from 300mg to 2400mg days 13 – 30 (adjustment if renal impairment).  33/46 completed study.  No reduction in incidence or intensity of post-amputation stump and phantom pain.
    16. 16. Chronic pain  Conclusions from other papers (under- powered, high dropout rates):  Incidence of burning pain significantly reduced but no effect on incidence of overall chronic pain, its intensity or the need for analgesics 3 months after surgery (mastectomies/lumpectomies with axillary dissection)  Borderline significant reduction in number of patients requiring analgesics at 3 months (same ops as above)  Incisional pain following hysterectomy similar in study and control groups at 3 month follow- up
    17. 17. So, the ‘answers’ 1. What is the evidence for Gabapentin reducing acute pain following orthopaedic surgery?  Body of evidence that acute pain can be reduced perioperatively using gabapentin  However, better evidence that only ‘early’ postop pain is significantly reduced  Few orthopaedic joint studies  Cochrane review on ‘established acute postop pain’ found little evidence for the use of single dose gabapentin  Summary  Evidence mainly supports opioid sparing effects of gabapentin when used perioperatively (for multiple surgical procedures). But, significantly higher incidence of sedation.  Gabapentin may have benefit for acute pain particularly in the early post-op period.  If it’s going to be used, should probably be given pre-emptively.
    18. 18. The answers 2. What is the evidence for Gabapentin reducing chronic pain following orthopaedic surgery?  Seems like a good idea but…  There doesn’t appear to be any good evidence.  Studies looking at other surgical procedures have been poorly performed.  Summary  Jury out.  The role of perioperative pain management preventing chronic pain is unproven.  As an aside:  Some patients may develop withdrawal from gabapentin (similar to alcohol withdrawal syndrome)
    19. 19. The answers 3. What doses of Gabapentin are recommended for peri- operative use?  Dose-response relationship has not been adequately addressed  However, optimal preemptive dose for lumbar discectomy thought to be 600mg (J Neuro Anesth 2005)  BJA recommended 900mg  Few studies used multiple dosing regimes (most simply one dose pre-op)  Only one orthopaedic study which looked at multiple doses (Effect of oral gabapentin on postop epidural analgesia, BJA 2006)  BJA review article recommends that ‘gabapentin given as multiple doses perioperatively offers no additional benefit in terms of pain reduction and opioid sparing when compared with a single preoperative dose’

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