Intravenous Acetaminophen Versus Placebo in Post-bariatric Surgery Multimodal Pain Management: a Meta-analysis of Randomized Controlled Trials

Transcriptomic signature, bioactivity and safety of a non-hepatotoxic analgesic generating AM404 in the midbrain PAG region

Safe and effective pain management is a critical healthcare and societal need. The potential for acute liver injury from paracetamol (ApAP) overdose; nephrotoxicity and gastrointestinal damage from chronic non-steroidal anti-inflammatory drug (NSAID) use; and opioids' addiction are unresolved challenges. We developed SRP-001, a non-opioid and non-hepatotoxic small molecule that, unlike ApAP, does not produce the hepatotoxic metabolite N-acetyl-p-benzoquinone-imine (NAPQI) and preserves hepatic tight junction integrity at high doses. CD-1 mice exposed to SRP-001 showed no mortality, unlike a 70% mortality observed with increasing equimolar doses of ApAP within 72 h. SRP-001 and ApAP have comparable antinociceptive effects, including the complete Freund's adjuvant-induced inflammatory von Frey model. Both induce analgesia via N-arachidonoylphenolamine (AM404) formation in the midbrain periaqueductal grey (PAG) nociception region, with SRP-001 generating higher amounts of AM404 than ApAP. Single-cell transcriptomics of PAG uncovered that SRP-001 and ApAP also share modulation of pain-related gene expression and cell signaling pathways/networks, including endocannabinoid signaling, genes pertaining to mechanical nociception, and fatty acid amide hydrolase (FAAH). Both regulate the expression of key genes encoding FAAH, 2-arachidonoylglycerol (2-AG), cannabinoid receptor 1 (CNR1), CNR2, transient receptor potential vanilloid type 4 (TRPV4), and voltage-gated Ca2+ channel. Phase 1 trial (NCT05484414) (02/08/2022) demonstrates SRP-001's safety, tolerability, and favorable pharmacokinetics, including a half-life from 4.9 to 9.8 h. Given its non-hepatotoxicity and clinically validated analgesic mechanisms, SRP-001 offers a promising alternative to ApAP, NSAIDs, and opioids for safer pain treatment.

Non-Opioid Analgesics and Adjuvants after Surgery in Adults with Obesity: Systematic Review with Network Meta-Analysis of Randomized Controlled Trials

Background/Objectives: Managing postoperative pain in patients with obesity is challenging. Although using a combination of pain relief methods is recommended for these patients, the true effectiveness of various intravenous non-opioid analgesics and adjuvants in multimodal anesthesia needs to be better defined. Methods: A systematic review and network meta-analysis was performed to evaluate the efficacy of nonsteroidal anti-inflammatory drugs (NSAIDs), acetaminophen, ketamine, α-2 agonists, lidocaine, magnesium, and oral gabapentinoids in adult surgical patients with obesity. The analysis aimed to compare these treatments to a placebo/no treatment or alternative analgesics, with a primary focus on postoperative pain and secondary endpoints including rescue analgesia, postoperative nausea and vomiting (PONV), and recovery quality. English-language randomized controlled trials across PubMed, Scopus, Web of Science, CINAHL, and EMBASE were considered. Quality and evidence certainty were assessed with the RoB 2 tool and GRADE, and data was analyzed with R software. Results: NSAIDs, along with acetaminophen, lidocaine, α-2 agonists, ketamine, and oral gabapentinoids, effectively reduce early postoperative pain. NSAIDs, particularly ibuprofen, as well as acetaminophen, ketamine, and lidocaine, also show benefits in later postoperative stages. Intravenous non-opioid analgesics and adjuvants show some degree of benefit in reducing PONV and the need for rescue analgesic therapy when using α-2 agonists alone or combined with oral gabapentinoids, notably decreasing the likelihood of PONV. Ketamine, lidocaine, and α-2 agonists are shown to enhance postoperative recovery and care quality. Conclusions: Intravenous non-opioid analgesics and adjuvants are valuable in multimodal anesthesia for pain management in adult surgical patients suffering from obesity.

The Dangers of Acetaminophen for Neurodevelopment Outweigh Scant Evidence for Long-Term Benefits

Based on available data that include approximately 20 lines of evidence from studies in laboratory animal models, observations in humans, correlations in time, and pharmacological/toxicological considerations, it has been concluded without reasonable doubt and with no evidence to the contrary that exposure of susceptible babies and children to acetaminophen (paracetamol) induces many, if not most, cases of autism spectrum disorder (ASD). However, the relative number of cases of ASD that might be induced by acetaminophen has not yet been estimated. Here, we examine a variety of evidence, including the acetaminophen-induced reduction of social awareness in adults, the prevalence of ASD through time, and crude estimates of the relative number of ASD cases induced by acetaminophen during various periods of neurodevelopment. We conclude that the very early postpartum period poses the greatest risk for acetaminophen-induced ASD, and that nearly ubiquitous use of acetaminophen during early development could conceivably be responsible for the induction in the vast majority, perhaps 90% or more, of all cases of ASD. Despite over a decade of accumulating evidence that acetaminophen is harmful for neurodevelopment, numerous studies demonstrate that acetaminophen is frequently administered to children in excess of currently approved amounts and under conditions in which it provides no benefit. Further, studies have failed to demonstrate long-term benefits of acetaminophen for the pediatric population, leaving no valid rationale for continued use of the drug in that population given its risks to neurodevelopment.

Oral versus intravenous acetaminophen for perioperative pain management in adult patients undergoing non-cardiac surgery: A quantile segmented regression analysis

STUDY OBJECTIVE

Determine whether preferential use of perioperative enteral acetaminophen is associated with changes in perioperative pain, narcotic administration, or time to meeting criteria for post anesthesia care unit (PACU) discharge, compared to preferential parenteral administration.

DESIGN

Retrospective Cohort with quantile segmented regression analysis. Groups determined by date of surgery, one year pre-initiative and one year post-initiative.

SETTING

Operating room and PACU of a tertiary academic medical center.

PATIENTS

Adult (age > 18 years), ASA status 1-5, non-pregnant patients undergoing non-cardiac surgery of less than six hours duration admitted to the PACU postoperatively.

INTERVENTIONS

A multidisciplinary initiative to preferentially utilize enteral over parenteral acetaminophen.

MEASUREMENTS

The primary outcome was narcotic consumption in the PACU. Secondary outcomes were intraoperative narcotic administration, pain score on PACU admission and discharge, and time to meeting criteria for PACU discharge.

RESULTS

24,701 patients were included in the analysis; 12,379 had surgery prior to the initiative and 12,322 after. Enteral acetaminophen administration increased preoperatively from 13.49% to 26.84%, and postoperatively from 43.16% to 51.45%, while intraoperative parenteral APAP use dropped from 43.23% to 6.81%. Quantile Segmented regression analysis after adjusting for period (pre versus postintervention), day, age, gender, inpatient status, and ASA class demonstrated a decrease in adjusted median perioperative acetaminophen dose (-175 mg P < 0.001), with no significant difference in level change of intraoperative or PACU narcotic administration. There was no significant difference in median time to meet criteria for PACU discharge, though there was a significant change in the slope, (-0.36, p = 0.007.) Median pain scores measured on a standard 0-10 numeric rating scale at PACU admission did not change, while median pain scores at PACU discharge decreased slightly (-0.24 p < 0.001). There was no change in the probability of PONV.

CONCLUSION

In adult patients undergoing non-cardiac surgery of <6 h duration, preferential use of enteral rather than parenteral acetaminophen is associated with non-inferior outcomes in narcotic requirements, pain scores, time to PACU discharge, and probability of PONV when compared with routine parenteral administration. Further studies are needed to validate these findings.

Efficacy and safety of patient-controlled thoracic epidural analgesia alone versus patient-controlled intravenous analgesia with acetaminophen after laparoscopic distal gastrectomy for gastric cancer: a propensity score-matched analysis

BACKGROUND

Laparoscopic gastrectomy is a common procedure for early gastric cancer treatment. Improving postoperative pain control enhances patient recovery after surgery. The use of multimodal analgesia can potentially enhance the analgesic effect, minimize side effects, and change the postoperative management. The purpose of this study was to evaluate and compare the efficacies of the use of patient-controlled intravenous analgesia with regular acetaminophen (PCIA + Ace) and patient-controlled thoracic epidural analgesia (PCEA) for postoperative pain control.

METHODS

We retrospectively collected the data of 226 patients who underwent laparoscopic distal gastrectomy (LDG) with delta-shaped anastomosis between 2016 and 2019. After 1:1 propensity-score matching, we compared 83 patients who used PCEA alone (PCEA group) with 83 patients who used PCIA + Ace (PCIA + Ace group). Postoperative pain was assessed using a numeric rating scale (NRS) with scores ranging from 0 to 10. An NRS score ≥ 4 was considered the threshold for additional intravenous rescue medication administration.

RESULTS

Although NRS scores at rest were comparable between the PCEA and PCIA + Ace groups, NRS scores of patients in the PCIA + Ace group during coughing or movement were significantly better than those of patients in the PCEA group on postoperative days 2 and 3. The frequency of additional rescue analgesic use was significantly lower in the PCIA + Ace group than in the PCEA group (1.1 vs. 2.7, respectively, p < 0.001). The rate of reduction or interruption of the patient-controlled analgesic dose was higher in the PCEA group than in the PCIA + Ace group (74.6% vs. 95.1%, respectively, p = 0.0002), mainly due to hypotension occurrence in the PCEA group. Physical recovery time, postoperative complication occurrence, and liver enzyme elevation incidence were not significantly different between groups.

CONCLUSIONS

PCIA + Ace can be safely applied without an increase in complications or deterioration in gastrointestinal function; moreover, PCIA + Ace use may provide better pain control than PCEA use in patients following LDG.

A randomized controlled trial of an enhanced recovery after surgery protocol in patients undergoing laparoscopic sleeve gastrectomy

BACKGROUND

The purpose of this study was to evaluate the effect of an enhanced recovery after surgery (ERAS) protocol on opioid and anti-emetic use, length of stay and safety after laparoscopic sleeve gastrectomy (LSG).

METHODS

Patients who underwent LSG between March 2018 and January 2019 at our accredited, high-volume bariatric surgery center were randomized to either standard of care (SOC) or ERAS. ERAS included a pre- and post-surgical medication regimen designed to reduce postoperative nausea, vomiting and pain. Outcomes included post-operative symptom scores, opioid use, anti-emetic use, time to achieve readiness for discharge (RFD) and inpatient and 30-day adverse events, readmissions and emergency department visits.

RESULTS

The final analysis included 130 patients, (SOC 65; ERAS 65). Groups did not differ on demographics or comorbidities. Relative to SOC, fewer ERAS patients utilized opioids in the hospital ward (72.3% vs. 95.4%; p < .001), peak pain scores were significantly lower, and median time to achieve RFD was shorter (28.0 h vs. 44.4 h; p = 0.001). More ERAS patients were discharged on post-operative day 1 (38.5% vs. 15.4%; p < .05). The overall use of rescue anti-emetic medications was not different between groups. Rates of postoperative 30-day events, readmissions, and emergency department visits did not differ between groups.

CONCLUSION

Relative to SOC, ERAS was associated with earlier discharge, lower pain scores, less frequent use of opioids and use in lower amounts after LSG with no differences in 30 day safety outcomes.

Implementation of a standardized multimodal pain regimen significantly reduces postoperative inpatient opioid utilization in patients undergoing bariatric surgery

BACKGROUND

Routine opioid use in surgical patients has received attention given the opioid epidemic and a renewed focus on the dangers and drawbacks of opioids in the postoperative setting. Little is known about opioid use in bariatric surgery, especially in the inpatient setting. We hypothesize that a standardized opioid-sparing protocol reduces postoperative inpatient opioid use in bariatric surgery patients.

METHODS

A retrospective cohort study was conducted of bariatric surgery patients at a single institution. From March to September 2019, a standardized intraoperative and postoperative opioid-sparing protocol was designed and implemented along with an educational program for patients regarding safe pain management. Inpatient opioid utilization in patients undergoing surgery in the preintervention phase between April and March 2019 was compared to patients from a postintervention phase of October 2019 to December 2020. Opioid utilization was measured in morphine milliequivalents (MME).

RESULTS

A total of 359 patients were included; 192 preintervention and 167 postintervention. Patients were similar demographically. For all patients, mean age was 44.1 years, mean BMI 49.2 kg/m2, and 80% were female. Laparoscopic sleeve gastrectomy was performed in 48%, laparoscopic gastric bypass in 34%, robotic sleeve gastrectomy in 17%, and robotic gastric bypass in 1%. In the postintervention phase inpatient opioid utilization was significantly lower [median 134.8 [79.0-240.8] MME preintervention vs. 61.5 [35.5-150.0] MME postintervention (p < 0.001)]. MME prescribed at discharge decreased from a median of 300 MME preintervention to 75 MME postintervention (p < 0.001). In the postintervention phase, 16% of patients did not receive an opioid prescription at discharge compared to 0% preintervention (p < 0.001). When examining by procedure, statistically significant reductions in opioid utilization were seen for each operation.

CONCLUSION

Implementation of a standardized intraoperative and postoperative multimodal pain regimen and educational program significantly reduces inpatient opioid utilization in patients undergoing bariatric surgery.

Efficacy and safety of intravenous acetaminophen (2 g/day) for reducing opioid consumption in Chinese adults after elective orthopedic surgery: A multicenter randomized controlled trial

Background: Acetaminophen is an important component of a multimodal analgesia strategy to reduce opioid consumption and pain intensity after an orthopedic surgery. The opioid-sparing efficacy of intravenous acetaminophen has been established at a daily dose of 4 g. However, it is still unclear for the daily dose of 2 g of acetaminophen, which is recommended by the China Food and Drug Administration Center for Drug Evaluation, in terms of its efficacy and safety.

Objectives: This study aimed to evaluate the efficacy and safety of intravenous acetaminophen at a daily dose of 2 g for reducing opioid consumption and pain intensity after orthopedic surgery.

Methods: In this multicenter, randomized, double-blind, placebo-controlled phase III trial, 235 patients who underwent orthopedic surgery were randomly assigned to receive intravenous acetaminophen 500 mg every 6 h or placebo. Postoperative morphine consumption, pain intensity at rest and during movement, and adverse events were analysed.

Results: For the mean (standard deviation) morphine consumption within 24 h after surgery, intravenous acetaminophen was superior to placebo both in the modified intention-to-treat analysis [8.7 (7.7) mg vs. 11.2 (9.2) mg] in the acetaminophen group and the placebo group, respectively. Difference in means: 2.5 mg; 95% confidence interval, 0.25 to 4.61; p = 0.030), and in the per-protocol analysis (8.3 (7.0) mg and 11.7 (9.9) mg in the acetaminophen group and the placebo group, respectively. Difference in means: 3.4 mg; 95% confidence interval: 1.05 to 5.77; p = 0.005). The two groups did not differ significantly in terms of pain intensity and adverse events.

Conclusion: Our results suggest that intravenous acetaminophen at a daily dose of 2 g can reduce morphine consumption by Chinese adults within the first 24 h after orthopedic surgery, but the extent of reduction is not clinically relevant.

Clinical Trial Registration: [ClinicalTrials.gov], identifier [NCT02811991].

Effect of Intravenous Paracetamol on Opioid Consumption in Multimodal Analgesia After Lumbar Disc Surgery: A Meta-Analysis of Randomized Controlled Trials

Background: Intravenous paracetamol, as an adjunct to multimodal analgesia, has been shown to successfully reduce opioid consumption after joint arthroplasty, abdominal surgery, and caesarean delivery. However, there are limited data on the opioid-sparing effect of intravenous paracetamol on lumbar disc surgery.

Objectives: The aim of this study was to investigate the effectiveness and safety of intravenous paracetamol for reducing opioid consumption in lumbar disc surgery. The primary outcome was cumulative opioid consumption within 24 h postoperatively.

Method: We followed the PRISMA-P guidelines and used GRADE to assess the quality of evidence. The review was registered in PROSPERO under the registration number CRD42021288168. Two reviewers conducted electronic searches in PubMed, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), Scopus, and Web of Science (Clarivate Analytics). Randomized controlled trials (RCTs) that compared the postoperative opioid consumption of intravenous paracetamol with placebo in lumbar discectomy were included.

Results: Five trials comprising a total of 271 patients were included. The overall opioid consumption within 24 h postoperatively was reduced [mean difference (MD), −10.61 (95% CI, −16.00 to −5.22) mg, p = 0.0001, I² = 90%] in patients with intravenous paracetamol. Intravenous paracetamol significantly reduced the postoperative pain scores at 1 h [MD, −2.37 (95%CI, −3.81 to −0.94), p = 0.001, I² = 82%], 2 h [MD, −3.17 (95%CI, −3.85 to −2.48), p < 0.00001, I² = 38%], 6 h [MD, −1.75 (95%CI, −3.10 to −0.40), p = 0.01], 12 h [MD, −0.96 (95%CI, −1.77 to −0.15), p = 0.02], and 24 h [MD, −0.97 (95%CI, −1.67 to −0.27), p = 0.006] compared with the placebo. There were no differences in postoperative adverse effects.

Conclusion: Intravenous paracetamol reduced postoperative opioid consumption and decreased postoperative pain scores without increasing adverse effects. The overall GRADE quality of the evidence was rated as low to moderate. Intravenous paracetamol appears to be an applicable option as an important part of multimodal analgesia for postoperative analgesia after lumbar disc surgery.

Systematic Review Registration:https://www.crd.york.ac.uk/prospero/, CRD42021288168.

Analgesic Efficacy of Gabapentin and Pregabalin in Patients Undergoing Laparoscopic Bariatric Surgeries: a Systematic Review and Meta-analysis

This meta-analysis investigated the effect of oral gabapentinoids (i.e., pregabalin and gabapentin) on analgesic consumption (i.e., primary outcome) and pain relief (i.e., secondary outcome) in patients following bariatric surgery. Analysis of five eligible trials published between 2010 and 2019 including 363 participants receiving gabapentinoids revealed a significantly lower morphine consumption [mean difference (MD) =  - 15.1 mg, p = 0.004; evidence certainty: low] and risk of nausea/vomiting [risk ratio (RR) = 0.49, p = 0.002; evidence certainty: high] at postoperative 6-24 h. There was also a lower pain score at postoperative 0-4 h (MD =  - 1.41, p < 0.00001; evidence certainty: low) and 6-12 h (MD =  - 0.9, p = 0.007; evidence certainty: low) compared with controls, while pain severity at postoperative 24 h was comparable between two groups. In summary, preoperative oral gabapentinoids optimized postoperative pain outcomes and reduced risk of nausea/vomiting following bariatric surgery.

Care of the Patient After Metabolic and Bariatric Surgery

Weight loss surgery, also known as metabolic and bariatric surgery (MBS), is an effective weight loss treatment and is associated with reduced mortality and improvements in obesity-related health conditions and quality of life. Postsurgical anatomical and physiologic changes include decreased absorption of micronutrients and alterations in gut-brain hormonal regulation that affect many aspects of health. Patients require ongoing monitoring of their physical and mental health for lasting success. Internists, particularly primary care clinicians, are in an ideal position to monitor for nonserious complications in the short and long term, adjust management of chronic diseases accordingly, and monitor for mental health changes. This article reviews key issues that internists should be aware of for supporting patients' health in the short and long term after MBS.

Paracetamol for multimodal analgesia

Pain and related disability remain a major social and therapeutic problem. Comorbidities and therapies increase drug interactions and side effects making pain management more compounded especially in the elderly who are the fastest-growing pain population. Multimodal analgesia consists of using two or more drugs and/or techniques that target different sites of pain, increasing the level of analgesia and decreasing adverse events from treatment. Paracetamol enhances multimodal analgesia in experimental and clinical pain states. Strong preclinical evidence supports that paracetamol has additive and synergistic interactions with anti-inflammatory, opioid and anti-neuropathic drugs in rodent models of nociceptive and neuropathic pain. Clinical studies in young and adult elderly patients confirm the utility of paracetamol in multimodal, non-opioid or opioid-sparing, therapies for the treatment of acute and chronic pain.

Perioperative Pain Management in Bariatric Anesthesia

Weight loss (bariatric) surgery is the most commonly performed elective surgical procedure in patients with morbid obesity. In this review, we provide an evidence-based update on perioperative pain management in bariatric anesthesia. We mention some newer preoperative aspects—medical optimization, physical preparation, patient education, and psychosocial factors—that can all improve pain management. In the intraoperative period, with bariatric surgery being almost universally performed laparoscopically, we emphasize the use of non-opioid adjuvant infusions (ketamine, lidocaine, and dexmedetomidine) and suggest some novel regional anesthesia techniques to reduce pain, opioid requirements, and side effects. We discuss some postoperative strategies that additionally focus on patient safety and identify patients at risk of persistent pain and opioid use after bariatric surgery. This review suggests that the use of a structured, step-wise, severity-based, opioid-sparing multimodal analgesic protocol within an enhanced recovery after surgery (ERAS) framework can improve postoperative pain management. Overall, by incorporating all these aspects throughout the perioperative journey ensures improved patient safety and outcomes from pain management in bariatric anesthesia.

Patients with sleep-disordered breathing for bariatric surgery

The prevalence of patients with obesity continues to rise worldwide and has reached epidemic proportions. There is a strong correlation between obesity and sleep-disordered breathing (SDB), and, in particular, obstructive sleep apnea (OSA). OSA is often undiagnosed in the surgical population. Bariatric surgery has been recognized as an effective treatment option for both obesity and OSA. Laparoscopic bariatric procedures, particularly laparoscopic sleeve gastrectomy (LSG), have become the most frequently performed procedures. OSA has been identified as an independent risk factor for perioperative complications and failure to recognize and prepare for patients with OSA is a major cause of postoperative adverse events, suggesting that all patients undergoing bariatric surgery should be screened preoperatively for OSA. These patients should be treated with an opioid-sparing analgesic plan and continuous positive airway pressure (CPAP) perioperatively to minimize respiratory complications. With the number of bariatric surgical patients with SDB likely to continue rising, it is critical to understand the best practices to manage this patient population.

Systematic Review of Systemic and Neuraxial Effects of Acetaminophen in Preclinical Models of Nociceptive Processing

Acetaminophen (APAP) in humans has robust effects with a high therapeutic index in altering postoperative and inflammatory pain states in clinical and experimental pain paradigms with no known abuse potential. This review considers the literature reflecting the preclinical actions of acetaminophen in a variety of pain models. Significant observations arising from this review are as follows: 1) acetaminophen has little effect upon acute nociceptive thresholds; 2) acetaminophen robustly reduces facilitated states as generated by mechanical and thermal hyperalgesic end points in mouse and rat models of carrageenan and complete Freund’s adjuvant evoked inflammation; 3) an antihyperalgesic effect is observed in models of facilitated processing with minimal inflammation (eg, phase II intraplantar formalin); and 4) potent anti-hyperpathic effects on the thermal hyperalgesia, mechanical and cold allodynia, allodynic thresholds in rat and mouse models of polyneuropathy and mononeuropathies and bone cancer pain. These results reflect a surprisingly robust drug effect upon a variety of facilitated states that clearly translate into a wide range of efficacy in preclinical models and to important end points in human therapy. The specific systems upon which acetaminophen may act based on targeted delivery suggest both a spinal and a supraspinal action. Review of current targets for this molecule excludes a role of cyclooxygenase inhibitor but includes effects that may be mediated through metabolites acting on the TRPV1 channel, or by effect upon cannabinoid and serotonin signaling. These findings suggest that the mode of action of acetaminophen, a drug with a long therapeutic history of utilization, has surprisingly robust effects on a variety of pain states in clinical patients and in preclinical models with a good therapeutic index, but in spite of its extensive use, its mechanisms of action are yet poorly understood.

The Efficacy of Acetominophen for Total Laparoscopic Hysterectomy

OBJECTIVE

Despite limited data, acetaminophen, along with other agents, is commonly included in enhanced recovery after surgery (ERAS) protocols following laparoscopic hysterectomy. We aimed to systematically review the efficacy of acetaminophen on the management of postoperative pain after laparoscopic hysterectomy.

METHODS

We searched PubMed, SCOPUS, Web of Science, and Cochrane Library databases for relevant clinical trials investigating the role of acetaminophen in the management of pain after laparoscopic hysterectomy. We performed the risk of bias according to Cochrane's risk of bias tool. We performed the analysis of homogeneous data under the fixed-effects model during the analysis of heterogeneous data under the random-effects model. The primary outcome was the assessment of pain score after 2, 6, 12, and 24 h.

RESULTS

A total of 495 patients in 13 trials were included in our meta-analysis. Acetaminophen was not superior at reducing postoperative pain scores. Further analysis at progressive temporal points revealed no further significance; effect size at after 2 h (SMD = -0.020, 95% CI (-0.216; 0.176)), 6 h (SMD = -0.115, 95% CI (-0.312; 0.083)), 12 h (SMD = -0.126, 95% CI (-0.277; 0.025)), or 24 h (SMD = 0.063, 95% CI (-0.065; 0.191)). Pooled analysis was heterogeneous (P < 0.1); therefore, we conducted a sensitivity analysis yielding homogeneous results. The drug did not reduce opioid need (MD = -0.16, 95% CI (-2.39, 2.06), P = 0.89).

CONCLUSION

We conclude that acetaminophen is not beneficial for reducing pain after laparoscopic hysterectomy. Other alternatives have better results. Caution should be given to the inclusion of acetaminophen in ERAS protocols designed for laparoscopic hysterectomy, especially as a single agent or to reduce opioid consumption.

The efficacy and safety of paracetamol for pain relief: an overview of systematic reviews

OBJECTIVE

To evaluate the efficacy and safety of paracetamol as an analgesic medication in a range of painful conditions.

STUDY DESIGN

Systematic review of systematic reviews of the analgesic effects of paracetamol in randomised, placebo-controlled trials. Conduct of systematic reviews was assessed with AMSTAR-2; confidence in effect estimates (quality of evidence) was assessed with the Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria.

DATA SOURCES

MEDLINE, EMBASE, PsycINFO, Cochrane Database of Systematic Reviews; systematic reviews published 1 January 2010 - 30 April 2020.

DATA SYNTHESIS

We extracted pain and adverse events outcomes from 36 systematic reviews that assessed the efficacy of paracetamol in 44 painful conditions. Continuous pain outcomes were expressed as mean differences (MDs; standardised 0-10-point scale); dichotomous outcomes were expressed as risk ratios (RRs). There is high quality evidence that paracetamol provides modest pain relief for people with knee or hip osteoarthritis (MD, -0.3 points; 95% CI, -0.6 to -0.1 points) and after craniotomy (MD, -0.8 points; 95% CI, -1.4 to -0.2 points); there is moderate quality evidence for its efficacy in tension-type headache (pain-free at 2 hours: RR, 1.3; 95% CI, 1.1-1.4) and perineal pain soon after childbirth (patients experiencing 50% pain relief: RR, 2.4; 95% CI, 1.5-3.8). There is high quality evidence that paracetamol is not effective for relieving acute low back pain (MD, 0.2 points; 95% CI, -0.1 to 0.4 points). Evidence regarding efficacy in other conditions was of low or very low quality. Frequency of adverse events was generally similar for people receiving placebo or paracetamol, except that transient elevation of blood liver enzyme levels was more frequent during repeated administration of paracetamol to patients with spinal pain (RR, 3.8; 95% CI, 1.9-7.4).

CONCLUSIONS

For most conditions, evidence regarding the effectiveness of paracetamol is insufficient for drawing firm conclusions. Evidence for its efficacy in four conditions was moderate to strong, and there is strong evidence that paracetamol is not effective for reducing acute low back pain. Investigations that evaluate more typical dosing regimens are required.

PROSPERO REGISTRATION

CRD42015029282 (prospective).

Review of Intravenous Acetaminophen for Analgesia in the Postoperative Setting

BACKGROUND

Acetaminophen is a non-opioid analgesic commonly utilized for pain control after several types of surgical procedures.

METHODS

This scoping primary literature review provides recommendations for intravenous (IV) acetaminophen use based on type of surgery.

RESULTS

Intravenous acetaminophen has been widely studied for postoperative pain control and has been compared to other agents such as NSAIDs, opioids, oral/rectal acetaminophen, and placebo. Some of the procedures studied include abdominal, gynecologic, orthopedic, neurosurgical, cardiac, renal, and genitourinary surgeries. Results of these studies have been conflicting and largely have not shown consistent clinical benefit.

CONCLUSION

Overall, findings from this review did not support the notion that IV acetaminophen has significant efficacy for postoperative analgesia. Given the limited clinical benefit of IV acetaminophen, especially when compared to the oral or rectal formulations, use is generally not justifiable.

Optimizing Perioperative Use of Opioids: A Multimodal Approach

Purpose of Review

The main purpose of this article is to review recent literature regarding multimodal analgesia medications, citing their recommended doses, efficacy, and side effects. The second part of this report will provide a description of drugs in different stages of development which have novel mechanisms with less side effects such as tolerance and addiction.

Recent Findings

Multimodal analgesia is a technique that facilitates perioperative pain management by employing two or more systemic analgesics along with regional anesthesia, when possible. Even though opioids and non-opioid analgesics remain the most common medication used for acute pain management after surgery, they have many undesirable side effects including the potential for misuse. Newer analgesics including peripheral acting opioids, nitric oxide inhibitors, calcitonin gene-related peptide receptor antagonists, interleukin-6 receptor antagonists and gene therapy are under intensive investigation.

Summary

A patient's first exposure to opioids is often in the perioperative setting, a vulnerable time when multimodal therapy can play a large role in decreasing opioid exposure. Additionally, the current shift towards faster recovery times, fewer post-operative complications and improved cost-effectiveness during the perioperative period has made multimodal analgesia a central pillar of Enhanced Recovery After Surgery (ERAS) protocols.

Consensus Statement for the Prescription of Pain Medication at Discharge after Elective Adult Surgery

This Consensus Statement provides recommendations on the prescription of pain medication at discharge from hospital for opioid-naïve adult patients who undergo elective surgery. It encourages health care providers (surgeons, anesthesiologists, nurses/nurse practitioners, pain teams, pharmacists, allied health professionals, and trainees) to (1) use nonopioid therapies and reduce the prescription of opioids so that fewer opioid pills are available for diversion and (2) educate patients and their families/caregivers about pain management options after surgery to optimize quality of care for postoperative pain. These recommendations apply to opioid-naïve adult patients who undergo elective surgery. This consensus statement is intended for use by health care providers involved in the management and care of surgical patients. A modified Delphi process was used to reach consensus on the recommendations. First, the authors conducted a scoping review of the literature to determine current best practices and existing guidelines. From the available literature and expertise of the authors, a draft list of recommendations was created. Second, the authors asked key stakeholders to review and provide feedback on several drafts of the document and attend an in-person consensus meeting. The modified Delphi stakeholder group included surgeons, anesthesiologists, residents, fellows, nurses, pharmacists, and patients. After multiple iterations, the document was deemed complete. The recommendations are not graded because they are mostly based on consensus rather than evidence.