Opioid-sparing effect, but limited analgesic efficacy, with preop gabapentinoids in THA
The efficacy of preoperative administration of gabapentin/pregabalin in improving pain after total hip arthroplasty: a meta-analysisBMC Musculoskelet Disord. 2016 Aug 30;17(1):373
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Seven randomized controlled trials were included in this meta-analysis evaluating the efficacy and safety of preoperative gabapentin and pregabalin for postoperative analgesia following total hip arthroplasty. In all studies, gabapentin and/or pregabalin were compared to either placebo or no intervention. Pooled results demonstrated significantly lower cumulative morphine consumption with gabapentin compared to control up to 24 hours after surgery, and with pregabalin compared to control up to 48 hours after surgery. In contrast, pooled pain scores at rest or on mobilization did not demonstrate significantly lower scores with either gabapentin or pregabalin compared to control. In fact, pain scores during mobilization after 48 hours were significantly higher among gabapentin groups compared to control groups.
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Were the criteria used for deciding which studies to include in the overview reported?
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Was the validity of all of the studies referred to in the text assessed with use of appropriate criteria (either in selecting the studies for inclusion or in analyzing the studies that were cited)?
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Were the findings of the relevant studies combined appropriately relative to the primary question that the overview addresses?
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Detsky AS, Naylor CD, O'Rourke K, McGeer AJ, L'Abbé KA. J Clin Epidemiol. 1992;45:255-65
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Why was this study needed now?
One of the most important areas of research regarding perioperative treatment of patients undergoing total hip arthroplasty is postoperative analgesia. Patient-controlled analgesia with opioids remains a standard method of analgesia, although the undesirable side-effects of opioids have led to an emphasis on trying to limit their administration to only rescue analgesia and improve primary treatment. Gabapentinoids, such as gabapentin and pregabalin, have been suggested as medications with possible analgesic efficacy in these patients.
What was the principal research question?
What are the efficacy and safety profiles of preoperative gabapentin and pregabalin, compared to control, for analgesia following total hip arthroplasty?
What were the important findings?
- Pooled cumulative morphine consumption was significantly lower among gabapentin groups compared to control after 24h (MD -2.65 [95%CI -3.67, -1.63]; p<0.001) but not 48h (MD 0.00 [95%CI -7.69, 7.69]; p=1.000), while it was significantly lower for pregabalin compared to control after both 24 (MD -19.42 [95%CI -11.72, -3.93]; p<0.001) and 48h (MD -33.02 [95%CI -45.86, -20.19]; p<0.001).
- VAS pain at rest and at 24h did not significantly differ between gabapentin and control (MD 0.32 [95%CI -0.03, 0.67]; p=0.076), and pregabalin and control (MD -3.05 [95%CI -11.63, 5.53]; p=0.486). VAS pain at rest was significantly higher with gabapentin compared to control after 48h (MD 0.41 [95%CI 0.00-0.81]; p=0.049).
- VAS pain with mobilization between gabapentin and control did not significantly differ after 24h (MD 0.72 [95%CI -0.23, 1.66]), and was significantly higher among gabapentin groups after 48h (MD 1.90 [95%CI 0.04-3.75]; p=0.045). No significant difference in VAS pain with mobilization between pregabalin and control was observed after 24h (MD -0.78 [95%CI -6.91, 5.35]; p=0.803).
- No significant difference between gabapentin/pregabalin groups overall and control groups was observed in the incidences of vomiting (RR 0.95 [95%CI 0.47-1.92]), dizziness (RR 0.82 [95%CI 0.51-1.33]), or pruritus (RR 0.89 [95%CI 0.57-1.39]). A significantly lower incidence of nausea was observed with gabapentin/pregabalin groups compared to control (RR 0.49 [95%CI 0.27-0.92]).
What should I remember most?
In total hip arthroplasty, an opioid-sparing effect was observed with preoperative gabapentin up to 24 hours after surgery, and with preoperative pregabalin up to 48 hours after surgery. However, neither treatment provided a significant benefit compared to the control group for pain at rest or on movement. In contrast, pooled pain scores during movement were actually higher in gabapentin groups compared to control groups after 48 hours.
How will this affect the care of my patients?
While there may be a short-term reduction in opioid requirement with the use of either gabapentin or pregabalin following total hip arthroplasty, these interventions do not appear to significantly reduce short-term pain scores in patients. Therefore, their role in postoperative analgesia following total hip arthroplasty should be scrutinized based on the currently available data. It is important to note limitations of the available body of evidence, as only 2-3 studies were available to separately assess the efficacy and safety of gabapentin and pregabalin each indicating the need to further large randomized controlled trials.
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