My answer may be self evident, but I think the inclusion of Gabapentin or Pregabalin in pre op and post op pain regimens is about the prevention of chronic post surgical pain, particularly after certain surgeries such as joint replacement. Chronic pain can develop due to poorly managed pain particularly in first 24-48 hours after surgery as a result of central neuronal sensitisation due to surgical trauma. The Gabapentinoids block or moderate this.

It is important to describe what we mean by pain. In this context gabapentin and pregabalin prevent and/or treat burning pain and/or shooting pain (i.e. flashing, radiating, tingling). But the target of these molecules is not the tenderness (mechanical allodynia) or the numbness (somaesthetic disorder)

Gabapentin affects voltage-dependent calcium channel subunit alpha-2/delta-1 (CACNA2D1). If this channel were associated with acute pain mechanisms (peripheral or central), one would think the drug to be useful in pre-op or post-op regimens. However, there is no evidence to suggest this action. Subsequently, there is really no scientific rationale to administer the drug peri-operatively. Alternatively, with some injury/trauma/surgery, CACNA2D1 is known to upregulate in the nervous system and it is this change that facilitates the beneficial actions of the drug.

In a recent study (from 2002 to 2011) 11trials were included, 8 were perioperative gabapentin trials, 4 ofwhich (i.e., 50%) found that gabapentin decreased the incidence of chronic pain that persisted for more than 2 months after surgery. All pregabalin trials (3 of 3) demonstrated that pregabalin decreased the incidence of CPSP, and 2 of those trials also found an improvement in postsurgical patient function. These findings in individual trials were confirmed by the meta-analysis, which found that gabapentin and pregabalin caused an overall moderate-to-large reduction in CPSP.

This is early evidence suggesting that the reduction in CPSP may be linked to the perioperative administration of these medications. However, there are several

shortcomings in the literature reviewed.

Article The Prevention of Chronic Postsurgical Pain Using Gabapentin...

But many questions remain in my mind: Are pain physicians ready to translate these results into general practice? Which type of surgery is really beneficiated by these drugs? Which is the optimal protocol (dose and timing of administration)? What about patients not allowed to oral feeding? and about adverse effects, are these drugs well tolerated?

Fassoulaki found multimodal analgesia with local anesthetics and gabapentin reduced analgesic consumption after breast surgery for cancer without side effects (2005).

there is no evidence based role of gabapentin in these pain conditions.

All guideline which recommend gabepentin in perioperative pain management were biased.

"there is no evidence based role of gabapentin in these pain conditions.

All guideline which recommend gabepentin in perioperative pain management were biased."

Where could be the mentioned guideliness find?

These drugs may be useful since they give pain relief. In additin they also produce sedation but my only concern is emesis which these drugs tend to cause in some patients

In a systematic narrative review (RCT 2006-2009) Gabapentin and pregabalin reduced pain and opioid consumption after surgery in confront with placebo, but comparisons with other standard post-operative regimens were not sufficient. Moreover, Gabapentin and pregabalin could seem not to have any influence on the prevention of PONV. So if their utility in the acute period of postoperative pain in still questionable what can we expect about the prevention of chronic pain 2 mouths after surgery?

Article Gabapentin and Pregabalin for the Acute Post-operative Pain ...