g-aminobutyric acid-pentanoid agents: efficacy, indications, contraindications

Which of the following statements is NOT true of the use of gabapentin as an analgesic?

A. Side effects of gabapentin include dizziness, sedation, gait disturbance, headache, difficulty with concentration, peripheral edema, and visual disturbances when used for longer periods of time.
B. Meta-analyses of perioperative gabapentin use noted no increased risk of sedation and dizziness with short duration prescription of gabapentinoids though this result may be confounded by the use of sedation and general anesthesia in this patient population.
C. The data is inadequate to recommend the optimal dose and duration of gabapentinoid use for acute postoperative pain control
D. Gabapentin’s effect as a multimodal analgesic agent has been shown to be very strong, resulting in reducing opioid consumption by greater than a morphine equivalent of 10mg in the first 24 hours after surgery, based on randomized controlled trials with good scientific validity.

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Correct Answer: D

Explanation:

In the most extensive meta-analysis to date of randomized controlled trials using gabapentin, Fabritius demonstrated that the effects of gabapentin on postoperative analgesia, when examining only trials with low risk of bias, has been minimal to modest, and less than a 5mg of morphine reduction in the first 24 hours after surgery. There are many randomized controlled trials looking at gabapentin’s efficacy in the perioperative period, but these studies are limited by low sample size and heterogeneous doses of gabapentin. In light of gabapentin’s minimal to modest effects and its known side effects when used chronically (dizziness and sedation most reported side effect), it would be difficult to make recommendations about optimal dosing of gabapentin in the perioperative setting and caution should be exercised when considering this drug in patients with cognitive impairment and patients at risk for falls. This systematic review by Fabritius also noted no difference in risks of dizziness and sedation in patients receiving gabapentin perioperatively, although use of general or neuraxial anesthesia would confound data collected on sedation and dizziness in the first 24 hours after surgery.

References:

Fabritius ML, Geisler A, Petersen PL. Gabapentin for post‐operative pain management–a systematic review with meta‐analyses and trial sequential analyses. Acta Anaesthesiol Scand. 2016 Jul 18; 60 (9), 1188-1208

Mathiesen O, Wetterslev J, Kontinen VK, Pommergaard HC, Nikolajsen L, Rosenberg J, et al. Adverse effects of perioperative paracetamol, NSAIDs, glucocorticoids, gabapentinoids and their combinations: a topical review. Acta Anaesthesiol Scand. 2014 Nov 1;58(10):1182–98

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