Page 137 Acute Pain Management

The following tick boxes represent conclusions based on clinical experience and expert
opinion.
 Based on the experience in chronic neuropathic pain states, it would seem reasonable to
use tricyclic antidepressants and selective serotonin re‐uptake inhibitors in the
management of acute neuropathic pain (S).
 To minimise adverse effects, particularly in elderly people, it is advisable to initiate
treatment with low doses (U).
4.3.4 Anticonvulsant drugs

Specific anticonvulsant agents used in the treatment of acute pain
Gabapentinoids (gabapentin/ pregabalin)
A number of meta‐analyses have shown that perioperative gabapentinoids improved analgesia
(at rest and with movement) and reduced postoperative opioid consumption, but increased
the incidence of sedation compared with placebo (Ho et al, 2006 Level I; Hurley et al, 2006 Level I;
Peng et al, 2007 Level I; Tiippana et al, 2007 Level I). Three of these meta‐analyses (Ho et al, 2006
Level I; Peng et al, 2007 Level I; Tiippana et al, 2007 Level I) also reported a decrease in vomiting
and pruritus; the NNT was 25 for nausea, 6 for vomiting and 7 for urinary retention (Tiippana et
al, 2007 Level I). The effects of gabapentin were not dose‐dependent in the range of 300 to
1200 mg. (Tiippana et al, 2007 Level I). After hysterectomy and spinal surgery specifically,
gabapentin improved pain relief and was opioid‐sparing, nausea was less in patients after CHAPTER 4
hysterectomy, and there was no difference in sedation (Mathiesen et al, 2007 Level I).
Trials analysed in these meta‐analyses used a wide variety of gabapentin dosing regimens. It is
therefore not possible to recommend a particular regimen and furthermore, conclusions
cannot be drawn regarding optimal treatment duration or potential long‐term benefits (such
as reduced CPSP).
Used as an adjunct to epidural analgesia, perioperative gabapentin reduced pain scores and
epidural analgesic requirements and improved patient satisfaction, despite an increase in
dizziness (Turan et al, 2006 Level II).
Gabapentin reduced pain and opioid consumption following acute burns (Cuignet et al, 2007
Level III‐3) and reduced neuropathic pain descriptors in a small case series of patients with
burns injuries (Gray et al, 2008 Level IV). Pregabalin reduced the intensity of itch and the
Neuropathic Pain Scale descriptor of ‘hot pain’ (Gray et al, 2008 Level II). It was also effective for
the treatment of neuropathic pain caused by traumatic or postsurgical nerve injury (Gordh et al,
2008 Level II). The incidence and intensity of postamputation pain was not reduced by
gabapentin administered in the first 30 days after amputation (Nikolajsen, Finnerup et al,
2006 Level II).
Sodium valproate
Sodium valproate did not improve acute nociceptive pain after surgery (Martin et al, 1988
Level II) and IV sodium valproate was ineffective in treating acute migraine (Tanen et al, 2003
Level II).
Specific anticonvulsant agents used in the treatment of chronic pain
Carbamazepine
A review of carbamazepine for the treatment of chronic neuropathic pain calculated a NNT of
1.8 (CI 1.4 to 2.8) for relief of trigeminal neuralgia; there were insufficient data for a NNT for
painful diabetic neuropathy to be calculated. The NNH for a minor adverse effect compared

Acute pain management: scientific evidence 89