Efficacy of intravenous paracetamol compared to dipyrone and parecoxib for postoperative pain management after minor-to-intermediate surgery: a randomised, double-blind trial:

Metamizole in the Management of Musculoskeletal Disorders: Current Concept Review

Metamizole, or dipyrone, has been used for decades as a non-narcotic analgesic, providing pain relief from musculoskeletal disorders and antipyretic and antispasmolytic properties. Despite being in use since the 1920s, its mechanism of action still needs to be discovered. Despite causing fewer adverse effects when compared to other analgesics, its harmful effects on the blood and lack of evidence regarding its teratogenicity make the usage of the drug questionable, which has led to it being removed from the drug market of various countries. This narrative review aims to provide a detailed insight into the mechanism of action and efficacy, comparing its effectiveness and safety with other classes of drugs and the safety profile of metamizole.

Adjuvants for balanced anesthesia in ambulatory surgery

Balanced anesthesia relies on the simultaneous administration of different drugs to attain an anesthetic state. The classic triad of anesthesia is a combination of a hypnotic, an analgesic, and a neuromuscular blocker. It is predominantly the analgesic pillar of this triad that became more and more supported by adjuvant therapy. The aim of this approach is to evolve into an opioid-sparing technique to cope with undesirable side effects of the opioids and is fueled by the opioid epidemic. The optimal strategy for balanced general anesthesia in ambulatory surgery must aim for a transition to a multimodal analgesic regimen dealing with acute postoperative pain and ideally reduce the most common adverse effects patients are faced with at home; sore throat, delayed awakening, memory disturbances, headache, nausea and vomiting, and negative behavioral changes. Over the years, this continuum of "multimodal general anesthesia" adopted many drugs with different modes of action. This review focuses on the most recent evidence on the different adjuvants that entered clinical practice and gives an overview of the different mechanisms of action, the potential as opioid-sparing or hypnotic-sparing drugs, and the applicability specifically in ambulatory surgery.

[Perioperative analgesia with nonopioid analgesics : Joint interdisciplinary consensus-based recommendations of the German Pain Society, the German Society of Anaesthesiology and Intensive Care Medicine and the German Society of Surgery]

BACKGROUND

Nonopioid analgesics are frequently used for perioperative analgesia; however, insufficient research is available on several practical issues. Often hospitals have no strategy for how to proceed, e.g., for informing patients or for the timing of perioperative administration of nonopioid analgesics.

METHODS

An expert panel representing the German national societies of pain, anaesthesiology and intensive care medicine and surgery developed recommendations for the perioperative use of nonopioid analgesics within a formal, structured consensus process.

RESULTS

The panel agreed that nonopioid analgesics shall be part of a multimodal analgesia concept and that patients have to be informed preoperatively about possible complications and alternative treatment options. Patients' history of pain and analgesic intake shall be evaluated. Patients at risk of severe postoperative pain and possible chronification of postsurgical pain shall be identified. Depending on the duration of surgery, nonopioid analgesics can already be administered preoperatively or intraoperatively so that plasma concentrations are sufficient after emergence from anesthesia. Nonopioid analgesics or combinations of analgesics shall be administered for a limited time only. An interdisciplinary written standard of care, comprising the nonopioid analgesic of choice, possible alternatives, adequate dosing and timing of administration as well as surgery-specific policies, have to be agreed upon by all departments involved. At discharge, the patient's physician shall be informed of analgesics given and those necessary after discharge. Patients shall be informed of possible side effects and symptoms and timely discontinuation of analgesic drugs.

CONCLUSION

The use of nonopioid analgesics as part of a perioperative multimodal concept should be approved and established as an interdisciplinary and interprofessional concept for the adequate treatment of postoperative pain.

[Perioperative analgesia with nonopioid analgesics : Joint interdisciplinary consensus-based recommendations of the German Pain Society, the German Society of Anaesthesiology and Intensive Care Medicine and the German Society of Surgery]

BACKGROUND

Nonopioid analgesics are frequently used for perioperative analgesia; however, insufficient research is available on several practical issues. Often hospitals have no strategy for how to proceed, e.g., for informing patients or for the timing of perioperative administration of nonopioid analgesics.

METHODS

An expert panel representing the German national societies of pain, anaesthesiology and intensive care medicine and surgery developed recommendations for the perioperative use of nonopioid analgesics within a formal, structured consensus process.

RESULTS

The panel agreed that nonopioid analgesics shall be part of a multimodal analgesia concept and that patients have to be informed preoperatively about possible complications and alternative treatment options. Patients' history of pain and analgesic intake shall be evaluated. Patients at risk of severe postoperative pain and possible chronification of postsurgical pain shall be identified. Depending on the duration of surgery, nonopioid analgesics can already be administered preoperatively or intraoperatively so that plasma concentrations are sufficient after emergence from anesthesia. Nonopioid analgesics or combinations of analgesics shall be administered for a limited time only. An interdisciplinary written standard of care, comprising the nonopioid analgesic of choice, possible alternatives, adequate dosing and timing of administration as well as surgery-specific policies, have to be agreed upon by all departments involved. At discharge, the patient's physician shall be informed of analgesics given and those necessary after discharge. Patients shall be informed of possible side effects and symptoms and timely discontinuation of analgesic drugs.

CONCLUSION

The use of nonopioid analgesics as part of a perioperative multimodal concept should be approved and established as an interdisciplinary and interprofessional concept for the adequate treatment of postoperative pain.

[Perioperative analgesia with nonopioid analgesics : Joint interdisciplinary consensus-based recommendations of the German Pain Society, the German Society of Anaesthesiology and Intensive Care Medicine and the German Society of Surgery]

Hintergrund

Nichtopioidanalgetika werden bei vielen Patienten zur perioperativen Analgesie eingesetzt. Zu einigen praktischen Fragen beim Einsatz von Nichtopioidanalgetika liegen z. T. nur wenig Informationen aus Studien vor, und in Krankenhäusern existieren häufig keine Konzepte zum Vorgehen, z. B. zur Patientenaufklärung und zum Zeitpunkt der perioperativen Gabe.

Methodik

Eine Expertengruppe der beteiligten Fachgesellschaften hat konsensbasierte Empfehlungen zum perioperativen Einsatz von Nichtopioidanalgetika erarbeitet und in einem strukturierten formalen Konsensusprozess verabschiedet.

Ergebnisse

Die Arbeitsgruppe stimmt überein, dass Nichtopioidanalgetika Bestandteil eines perioperativen multimodalen Analgesiekonzepts sein sollen und Patienten präoperativ über Nutzen, Risiken und alternative Behandlungsmöglichkeiten aufgeklärt werden sollen. Die präoperative Patienteninformation und -edukation soll auch eine Schmerz- und Analgetikaanamnese umfassen und Patienten mit Risikofaktoren für starke Schmerzen und eine Schmerzchronifizierung sollen identifiziert werden. Unter Berücksichtigung von Kontraindikationen können Nichtopioidanalgetika abhängig von der Operationsdauer auch schon prä- oder intraoperativ gegeben werden, um nach Beendigung der Anästhesie ausreichende Plasmakonzentrationen zu erzielen. Nichtopioidanalgetika oder Kombinationen von (Nichtopioid‑)Analgetika sollen nur für einen begrenzten Zeitraum gegeben werden. Ein gemeinsam erarbeiteter abteilungsübergreifender Behandlungsstandard mit dem Nichtopioidanalgetikum erster Wahl, weiteren Therapieoptionen sowie adäquaten Dosierungen, ergänzt durch eingriffsspezifische Konzepte, soll schriftlich hinterlegt werden. Bei Entlassung aus dem Krankenhaus soll der nachbehandelnde Arzt zu perioperativ gegebenen und aktuell noch eingenommenen Analgetika schriftliche Informationen erhalten. Patienten sollen zu möglichen Nebenwirkungen der Analgetika und ihrer Symptome, die auch nach Krankenhausentlassung auftreten können, und die befristete Einnahmedauer informiert werden.

Schlussfolgerung

Die Anwendung von Nichtopioidanalgetika soll als Bestandteil eines perioperativen multimodalen Analgesiekonzepts mit klaren Vorgaben zu Indikationen, Kontraindikationen, Dosierungen und Behandlungsdauer in einem abteilungsübergreifenden Behandlungsstandard schriftlich hinterlegt werden.

Zusatzmaterial online

Die Offenlegung von Interessen ist in der Online-Version dieses Artikels (10.1007/s00104-021-01421-w) enthalten.

Preventive Analgesia, Hemodynamic Stability, and Pain in Vitreoretinal Surgery

Background and Objectives: Although vitreoretinal surgery (VRS) is most commonly performed under regional anaesthesia (RA), in patients who might be unable to cooperate during prolonged procedures, general anaesthesia (GA) with intraprocedural use of opioid analgesics (OA) might be worth considering. It seems that the surgical pleth index (SPI) can be used to optimise the intraprocedural titration of OA, which improves haemodynamic stability. Preventive analgesia (PA) is combined with GA to minimise intraprocedural OA administration. Materials and Methods: We evaluated the benefit of PA combined with GA using SPI-guided fentanyl (FNT) administration on the incidences of PIPP (postprocedural intolerable pain perception) and haemodynamic instability in patients undergoing VRS (p < 0.05). We randomly assigned 176 patients undergoing VRS to receive GA with SPI-guided FNT administration alone (GA group) or with preventive topical 2% proparacaine (topical anaesthesia (TA) group), a preprocedural peribulbar block (PBB) using 0.5% bupivacaine with 2% lidocaine (PBB group), or a preprocedural intravenous infusion of 1.0 g of metamizole (M group) or 1.0 g of paracetamol (P group). Results: Preventive PBB reduced the intraprocedural FNT requirement without influencing periprocedural outcomes (p < 0.05). Intraprocedural SPI-guided FNT administration during GA resulted in PIPP in 13.5% of patients undergoing VRS and blunted the periprocedural effects of preventive intravenous and regional analgesia with respect to PIPP and haemodynamic instability. Conclusions: SPI-guided FNT administration during GA eliminated the benefits of preventive analgesia in the PBB, TA, M, and P groups following VRS.

[Considerations concerning the perioperative use of metamizole]

BACKGROUND

The non-opioid analgesic metamizole (dipyrone) is approved for the treatment of severe pain and is often used in the perioperative period. As it can cause agranulocytosis, a severe adverse event, its perioperative administration is controversially discussed.

OBJECTIVE

Is there enough evidence for a high risk of metamizol-induced agranulocytosis (MIA)? What are the consequences of its perioperative use with respect to the risk profiles of alternative analgesics?

MATERIAL AND METHODS

Rapid review of the literature on the risk of MIA and adverse effects of non-opioid analgesics.

RESULTS

The incidence of MIA is estimated to be one case per million inhabitants per year. The risk seems low compared to other drugs associated with a risk of agranulocytosis, such as antithyroid drugs and ticlopidine. The risk profile of metamizole concerning hepatotoxicity, nephrotoxicity, bleeding and cardiovascular adverse effects is favorable compared to other non-opioid analgesics. None of the non-opioid analgesics are licensed to be administered intraoperatively.

CONCLUSION

The perioperative use of metamizole is possible after a thorough evaluation of the indications as it provides good analgesia with a generally favorable side effect profile and is administered intravenously. The risk of agranulocytosis is small but needs to be mentioned during patient informed consent in order to optimize early recognition. Intraoperative administration aims at reducing the expected severe postoperative pain. A documentation and justification for the evaluation of the indications are recommended.

Metamizole vs. ibuprofen at home after day case surgery: A double-blind randomised controlled noninferiority trial

BACKGROUND

NSAIDs and paracetamol are the cornerstones of pain treatment after day case surgery. However, NSAIDs have numerous contraindications and consequently are not suitable in up to 25% of patients. Metamizole is a non-opioid compound with a favourable gastro-intestinal and cardiovascular profile compared with NSAIDs.

OBJECTIVES

The study aimed to assess if a combination of metamizole and paracetamol is noninferior to a combination of ibuprofen and paracetamol in treating pain at home after painful day case surgery.

DESIGN

A double-blind randomised controlled trial.

SETTING

Single centre.

PATIENTS

Two hundred patients undergoing elective ambulatory haemorrhoid surgery, arthroscopic shoulder or knee surgery, or inguinal hernia repair.

INTERVENTION

Patients were randomly allocated to receive either metamizole and paracetamol (n = 100) or ibuprofen and paracetamol (n = 100) orally for four days.

MAIN OUTCOME MEASURES

Average postoperative pain intensity using a numerical rating scale and use of rescue medication were measured in the postanaesthesia care unit (PACU) and on postoperative days (POD) 1 to 3. A difference in mean numerical rating scale score of 1 point or less was considered noninferior. Adverse effects of study medication and satisfaction with study medication were measured on PODs 1 to 3 by telephone follow-up.

RESULTS

In the PACU, the difference in mean ± SD pain score between metamizole and paracetamol and ibuprofen and paracetamol was 0.85 ± 0.78. From POD 1 to 3, this difference was lower than 1, resulting in noninferiority. Rescue opioid consumption in the PACU and on PODs 1 and 3 was not significantly different between treatment groups. Rescue opioid consumption on POD2 was significantly higher in the ibuprofen and paracetamol group (P = 0.042). Adverse effects of study medication and overall patient satisfaction were similar in both groups.

CONCLUSION

Paracetamol/metamizole and paracetamol/ibuprofen are equally effective in treatment of acute postoperative pain at home after ambulatory surgery with comparable patient satisfaction levels.

TRIAL REGISTRATION

European Union Clinical Trials Register 2015-003987-35.

Emergence times and airway reactions during general anaesthesia with remifentanil and a laryngeal mask airway: A multicentre randomised controlled trial

BACKGROUND

Avoidance of airway complications and rapid emergence from anaesthesia are indispensable for the use of a laryngeal mask airway (LMA). Evidence from adequately powered randomised studies with a low risk of bias for the optimal anaesthetic in this context is limited.

OBJECTIVE

We tested the hypothesis that when using remifentanil-based intra-operative analgesia, desflurane would be the most suitable anaesthetic: with noninferiority in the occurrence of upper airway complications and superiority in emergence times compared with sevoflurane or propofol.

DESIGN

A randomised, multicentre, partially double-blinded, three-arm, parallel-group study.

SETTING

Two university and two regional German hospitals, from February to October 2015.

PATIENTS

A total of 352 patients (age 18 to 75 years, ASA physical status I to III, BMI less than 35 kg m⁻² and fluent in German) were enrolled in this study. All surgery was elective with a duration of 0.5 to 2 h, and general anaesthesia with a LMA was feasible.

INTERVENTION

The patients were randomised to receive desflurane, sevoflurane or propofol anaesthesia.

MAIN OUTCOME MEASURES

This study was powered for the primary outcome ‘time to state date of birth’ and the secondary outcome ‘intra-operative cough’. Time to emergence from anaesthesia and the incidence of upper airway complications were assessed on the day of surgery.

RESULTS

The primary outcome was analysed for 343 patients: desflurane (n=114), sevoflurane (n=111) and propofol (n=118). The desflurane group had the fastest emergence. The mean (± SD) times to state the date of birth following desflurane, sevoflurane and propofol were 8.1 ± 3.6, 10.1 ± 4.0 and 9.8 ± 5.1 min, respectively (P < 0.01). There was no difference in upper airway complications (cough and laryngospasm) across the groups, but these complications were less frequent than in previous studies.

CONCLUSION

When using a remifentanil infusion for intra-operative analgesia in association with a LMA, desflurane was associated with a significantly faster emergence and noninferiority in the incidence of intra-operative cough than either sevoflurane or Propofol.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02322502; EudraCT identifier: 2014-003810-96.

Comparison of the effects of intravenous Dexketoprofen Trometamol versus Paracetamol on postoperative analgesia in patients undergoing Septoplasty: A randomised double-blind clinical trial

Background and Objective:

Septoplasty operations are associated with moderate to severe postoperative pain which has unfavourable effects on patient’s recovery and postoperative outcome. The aim of this study was to compare effects of intravenous paracetamol and dexketoprofen on postoperative analgesia, tramadol consumption and side effects after septoplasty.

Methods:

In total 72 patients (aged 18–65 years) who had undergone an elective septoplasty from August 2013 to January 2015 in Baskent University Faculty of Medicine, in the Department of Anesthesiology and Reanimation Clinics were included in this study. The patients were randomised into one of two groups: those who received intravenous paracetamol; and those who received intravenous dexketoprofen. All patients were treated with tramadol for 24 hour postoperatively. The primary endpoint was pain intensity as measured by a visual analogue scale (VAS). Tramadol consumption and drug related side effects were also recorded.

Results:

The pain scores in the dexketoprofen group were significantly lower at recovery, 15 and 30 minutes and two hour (p< 0.05). The pain scores had no difference at other time points. Tramadol consumption in the recovery period was significantly lower in the dexketoprofen group, but cumulative tramadol consumption did not differ between the groups. The incidence of nausea was lower but not statistically significant in the dexketoprofen group at 15 and 30 minutes and two hour.

Conclusions:

Compared with paracetamol, preemptive dexketoprofen is associated with lower VAS scores and tramadol consumption in the early postoperative period after septoplasty. However, the cumulative tramadol consumption did not significantly differ between the groups.

The Comparison of Preventive Analgesic Effects of Ketamine, Paracetamol and Magnesium Sulfate on Postoperative Pain Control in Patients Undergoing Lower Limb Surgery: A Randomized Clinical Trial

Background

In considering the importance of postoperative pain management and its consequences on its related secondary outcomes including nausea, vomiting, and operation-related complications, we aimed to compare the effectiveness of the three analgesic agents including ketamine, paracetamol, and magnesium sulfate for postoperative pain relief and associated consequences in this trial.

Materials and Methods

In this double-blinded randomized control clinical trial, patients scheduled for elective lower extremity orthopedic surgery under general anesthesia were enrolled and randomized into four groups for receiving intravenous ketamine (0.25 mg/kg), paracetamol (15 mg/kg), magnesium sulfate (7.5 mg/kg), and placebo (normal saline), immediately after the induction of anesthesia. Postoperative pain scores, analgesic, and metoclopramide use, and frequency of vomiting and satisfaction score of studied patients in the four studied groups during the 6 h, 6-12 h, and 12-24 h after recovery were recorded and compared.

Results

In this trial, thirty patients randomized in each studied groups. Mean of postoperative pain score was significantly lower in ketamine group than others during 24 h after recovery (P < 0.001). Mean of additive analgesic use was significantly lower in ketamine group during 12 h after recovery (P < 0.001), but it was not significantly different during 12-24 h after recovery (P = 0.12). Mean of vomiting frequency and metoclopramide use was not different between groups (P > 0.05). Excellent and good satisfaction score were significantly higher in ketamine group than other groups (P = 0.04).

Conclusions

Ketamine has more superior effect for during recovery and postoperative pain controlling and analgesic use than paracetamol and magnesium sulfate.

Reduced anaesthetic requirements and postoperative analgesics in patients undergoing laparoscopic cholecystectomy: premedication with intravenous paracetamol versus ketorolac, a double blind and randomised clinical trial

OBJECTIVE

To compare the effects of premedication with intravenous paracetamol versus ketorolac, in decreasing intraoperative anaesthetic and postoperative opioid analgesics requirements in patients undergoing laparoscopic cholecystectomy.

METHOD

An experimental, prospective, comparative, double blind, and randomised clinical trial was conducted to determine intraoperative opioid requirements, and pain and analgesic requirements in the postoperative period in 100 healthy patients undergoing laparoscopic cholecystectomy. They were randomised into 2 groups: Group 1: pre-medicated with paracetamol 1g, and Group 2: with ketorolac 30mg (both administered intravenously 30minutes prior to surgery).

RESULTS

There were no statistically significant differences between groups as regards intraoperative remifentanil use (Group 1: 0.0739±0.016μg/kg/min, Group 2: 0.0741±0.018μg/kg/min). The number of patients in Group 2 that had values of VAS>4 points (22.4%) was lower than in Group 1 (28.6%), but with no statistically significant difference. Of the patients who needed postoperative opioid rescue, most required a single rescue and application of analgesics during hospitalisation, that prevailed between 3 and 12hours, without any significant differences between groups. No adverse effects were observed in the study sample.

CONCLUSION

Paracetamol 1g IV given preoperatively decreased anaesthetic requirements and the need for postoperative analgesics similar to the preoperative administration of ketorolac 30mg IV.

Parecoxib, propacetamol, and their combination for analgesia after total hip arthroplasty: a randomized non-inferiority trial

BACKGROUND

This study assessed non-inferiority of parecoxib vs. combination parecoxib+propacetamol and compared the opioid-sparing effects of parecoxib, propacetamol, and parecoxib+propacetamol vs. placebo after total hip arthroplasty.

METHODS

In this randomized, placebo-controlled, parallel-group, non-inferiority study, patients received one of four IV treatments after surgery: parecoxib 40 mg bid (n = 72); propacetamol 2 g qid (n = 71); parecoxib 40 mg bid plus propacetamol 2 g qid (n = 72); or placebo (n = 38) with supplemental IV patient-controlled analgesia (morphine). Patients and investigators were blinded to treatment. Pain intensity at rest and with movement was assessed regularly, together with functional recovery (modified Brief Pain Inventory-Short Form) and opioid-related side effects (Opioid-Related Symptom Distress Scale) questionnaires up to 48 h.

RESULTS

After 24 h, cumulative morphine consumption was reduced by 59.8% (P < 0.001), 38.9% (P < 0.001), and 26.8% (P = 0.005) in the parecoxib+propacetamol, parecoxib, and propacetamol groups, respectively, compared with placebo. Parecoxib did not meet criteria for non-inferiority to parecoxib+propacetamol. Parecoxib+propacetamol and parecoxib significantly reduced least-squares mean pain intensity scores at rest and with movement compared with propacetamol (P < 0.05). One day after surgery, parecoxib+propacetamol significantly reduced opioid-related symptom distress and decreased pain interference with function compared with propacetamol or placebo.

CONCLUSION

Parecoxib and parecoxib+propacetamol provided significant opioid-sparing efficacy compared with placebo; non-inferiority of parecoxib to parecoxib+propacetamol was not demonstrated. Opioid-sparing efficacy was accompanied by significant reductions in pain intensity on movement, improved functional outcome, and less opioid-related symptom distress. Study medications were well tolerated.

Evaluation of the Analgesic Efficacy of Dexketoprofen Added to Paracetamol

OBJECTIVE

Multimodal analgesic methods are preferred for the treatment of postoperative pain; as a result, the additive effects of analgesics are provided while probable side effects are avoided. The current study aimed to compare the effects of the combination of dexketoprofen and paracetamol with regard to postoperative pain therapy.

METHODS

Ninety-six patients who underwent non-malignant gynaecological laparotomy operations were included in this study. Patients were randomized into 3 groups. Group D received 50 mg intravenous dexketoprofen 15 minutes before the end of the operation and 8 and 16 hours after the operation. Group P received 1 g intravenous paracetamol and Group DP received the combination of 500 mg paracetamol and 25 mg dexketoprofen at the same time intervals. All patients received morphine infusion after operation. Total morphine consumption at 24 hours, visual analog scale, patient satisfaction and side effects were investigated.

RESULTS

Comparison of the visual analog scale scores revealed that the Group DP presented lower scores at 24th hours compared to the other groups; and the difference between Group DP and Group D was statistically significant. Total morphine consumption was not significantly different between the three groups. The minimum number of side effects was observed in the Group DP.

CONCLUSION

Co-administration of paracetamol, dexketoprofen and morphine provided good analgesia and fewer side effects in gynaecological abdominal surgery.

Metamizole versus ibuprofen at home after day surgery: study protocol for a randomised controlled trial

BACKGROUND

Postoperative pain and, in a more extended perspective, quality of recovery (QOR) should be considered the principal endpoints after day surgery. Non-steroidal anti-inflammatory drugs (NSAIDs) and paracetamol are a cornerstone of pain treatment after painful day surgery. Nevertheless, NSAIDs are not always sufficiently effective, have numerous contraindications, and consequently are not suitable in up to 25 % of all patients. Metamizole is a non-opioid compound with a favourable gastrointestinal, cardiovascular and cerebrovascular profile compared to NSAIDs. The aim of this study is to assess if a combination of metamizole and paracetamol is non-inferior to a combination of ibuprofen and paracetamol in the treatment of acute postoperative pain at home after painful day case surgery. In addition, we aim to assess and compare quality of recovery (QOR) profiles of both groups.

METHODS/DESIGN

This is an investigator-initiated, double-blind, randomised controlled, non-inferiority trial. A total of 200 patients undergoing elective haemorrhoid surgery, arthroscopic shoulder or knee surgery, or inguinal hernia repair in a day care setting will be randomised to receive either a combination of metamizole and paracetamol (MP) or a combination of ibuprofen and paracetamol (IP). Participants will take study medication orally for 4 days. Primary endpoints are average postoperative pain intensity measured by an 11-point Numeric Rating Scale at postoperative day 1 and QOR profile measured by the Functional Recovery Index (FRI), the 1-item Global Surgical Recovery (GSR) index and the EuroQol (EQ-5D) questionnaire at days 1, 2, 3, 4, 7, 14 and 28 postoperatively. Secondary outcomes include compliance with study medication, adverse effects of study medication, use of rescue medication and satisfaction with study medication, surgery and hospital care and telephone follow-up.

DISCUSSION

This study will provide clinical evidence on the analgesic efficacy and safety of a combination of metamizole and paracetamol in treating postoperative pain at home after painful day surgery. This study may also provide an insight into QOR profile after four different types of surgery and into the interrelationship between three different instruments used to assess QOR.

TRIAL STATUS

Recruitment is currently ongoing.

TRIAL REGISTRATION

European Union Clinical Trials Register 2015-003987-35 . Registered 10 November 2015.

Single dose intravenous paracetamol or intravenous propacetamol for postoperative pain

BACKGROUND

This is an updated version of the original Cochrane review published in Issue 10, 2011. Paracetamol (acetaminophen) is the most commonly prescribed analgesic for the treatment of acute pain. It may be administered orally, rectally, or intravenously. The efficacy and safety of intravenous (IV) formulations of paracetamol, IV paracetamol, and IV propacetamol (a prodrug that is metabolized to paracetamol), compared with placebo and other analgesics, is unclear.

OBJECTIVES

To assess the efficacy and safety of IV formulations of paracetamol for the treatment of postoperative pain in both adults and children.

SEARCH METHODS

We ran the search for the previous review in May 2010. For this update, we searched the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 1), MEDLINE (May 2010 to 16 February 2016), EMBASE (May 2010 to 16 February 2016), LILACS (2010 to 2016), a clinical trials registry, and reference lists of reviews for randomized controlled trials (RCTs) in any language and we retrieved articles.

SELECTION CRITERIA

Randomized, double-blind, placebo- or active-controlled single dose clinical trials of IV paracetamol or IV propacetamol for acute postoperative pain in adults or children.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data, which included demographic variables, type of surgery, interventions, efficacy, and adverse events. We contacted study authors for additional information. We graded each included study for methodological quality by assessing risk of bias and employed the GRADE approach to assess the overall quality of the evidence.

MAIN RESULTS

We included 75 studies (36 from the original review and 39 from our updated review) enrolling a total of 7200 participants.Among primary outcomes, 36% of participants receiving IV paracetamol/propacetamol experienced at least 50% pain relief over four hours compared with 16% of those receiving placebo (number needed to treat to benefit (NNT) = 5; 95% confidence interval (CI) 3.7 to 5.6, high quality evidence). The proportion of participants in IV paracetamol/propacetamol groups experiencing at least 50% pain relief diminished over six hours, as reflected in a higher NNT of 6 (4.6 to 7.1, moderate quality evidence). Mean pain intensity at four hours was similar when comparing IV paracetamol and placebo, but was seven points lower on a 0 to 100 visual analog scale (0 = no pain, 100 = worst pain imaginable, 95% CI -9 to -6, low quality evidence) in those receiving paracetamol at six hours.For secondary outcomes, participants receiving IV paracetamol/propacetamol required 26% less opioid over four hours and 16% less over six hours (moderate quality evidence) than those receiving placebo. However, this did not translate to a clinically meaningful reduction in opioid-induced adverse events.Meta-analysis of efficacy comparisons between IV paracetamol/propacetamol and active comparators (e.g., opioids or nonsteroidal anti-inflammatory drugs) were either not statistically significant, not clinically significant, or both.Adverse events occurred at similar rates with IV paracetamol or IV propacetamol and placebo. However, pain on infusion occurred more frequently in those receiving IV propacetamol versus placebo (23% versus 1%). Meta-analysis did not demonstrate clinically meaningful differences between IV paracetamol/propacetamol and active comparators for any adverse event.

AUTHORS' CONCLUSIONS

Since the last version of this review, we have found 39 new studies providing additional information. Most included studies evaluated adults only. We reanalyzed the data but the results did not substantially alter any of our previously published conclusions. This review provides high quality evidence that a single dose of either IV paracetamol or IV propacetamol provides around four hours of effective analgesia for about 36% of patients with acute postoperative pain. Low to very low quality evidence demonstrates that both formulations are associated with few adverse events, although patients receiving IV propacetamol have a higher incidence of pain on infusion than both placebo and IV paracetamol.

Single dose dipyrone (metamizole) for acute postoperative pain in adults

BACKGROUND

Dipyrone (metamizole) is a nonsteroidal anti-inflammatory drug used in some countries to treat pain (postoperative, colic, cancer, and migraine); it is banned in other countries because of an association with life-threatening blood disorders. This review replaces a 2010 Cochrane review that has been withdrawn.

OBJECTIVES

To assess the analgesic efficacy and associated adverse events of single dose dipyrone for moderate to severe acute postoperative pain using methods that permit comparison with other analgesics evaluated in standardised trials using almost identical methods and outcomes.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and LILACS to 11 August 2015; the Oxford Pain Relief Database; two clinical trial registries; and the reference lists of articles.

SELECTION CRITERIA

We included randomised, double-blind, placebo-controlled trials of single dose dipyrone for relief of established moderate to severe postoperative pain in adults. We accepted oral, rectal, intramuscular, and intravenous routes of administration.

DATA COLLECTION AND ANALYSIS

Two review authors independently considered studies for inclusion in the review, assessed risk of bias, and extracted data. We used summed total pain relief or pain intensity difference (TOTPAR or SPID) over four to six hours to calculate the number of participants achieving at least 50% pain relief. From derived results, we calculated the risk ratio and number needed to treat for an additional beneficial outcome (NNT), with 95% confidence intervals (CI), for one participant to experience at least 50% pain relief over four to six hours compared to placebo. We looked at use of rescue medication and time to use of rescue medication as additional measures of efficacy. We also looked for information on adverse events and withdrawals.

MAIN RESULTS

We included eight studies, involving 809 participants, comparing oral dipyrone 500 mg (143 participants), oral dipyrone 1000 mg (57 participants), and intramuscular dipyrone 2000 mg (35 participants) with placebo (236 participants). In addition to placebo, all studies used active controls (ibuprofen, paracetamol, aspirin, flurbiprofen, ketoprofen; 338 participants). Seven studies used the oral route of administration, and one study used the intramuscular route. The mean age ranged from 23 to 62 years. Six studies included both men and women, and two studies included only women. All the studies were small, but were otherwise of moderate to good quality.Over 70% of participants experienced our primary outcome of at least 50% pain relief over four to six hours with oral dipyrone 500 mg compared to 30% with placebo (five studies, 288 participants; NNT 2.4 (95% CI 1.8 to 3.1)) (moderate quality evidence). There were insufficient data to assess other doses or routes of administration of dipyrone.Fewer participants needed rescue medication within four to six hours with dipyrone 500 mg than with placebo (7% with dipyrone versus 34% with placebo; four studies, 248 participants) (low quality evidence).The data on numbers of participants experiencing any adverse event was inconsistently reported and no analysis was possible. No serious adverse events or adverse event withdrawals were reported (very low quality evidence).There were too few data to compare dipyrone directly with other active treatments.

AUTHORS' CONCLUSIONS

Based on very limited information, a single dose of dipyrone 500 mg provides good pain relief to about 70% of people treated, compared to about 30% with placebo. For every five people given dipyrone 500 mg, two people would experience this level of pain relief over four to six hours who would not have done with placebo, and fewer people would need rescue medication.We were unable to compare dipyrone directly with other active treatments, or to assess the effects of different doses or routes of administration, or the number of participants experiencing adverse events, because of insufficient data and inadequate reporting.

[Prehospital analgesia by paramedics in Rhineland-Palatinate : Feasability, analgesic effectiveness and safety of intravenous paracetamol]

BACKGROUND

In contrast to the widespread practice in life-threatening emergencies, delegation of medical pain therapy to paramedics by the medical director  of Emergency Medical Services, EMS, are still the exception in Germany. This is due to the fact that in non-life-threatening situations, the expected benefit and potential side effects of drug therapy have to be carefully weighed. In addition, in Germany federal law generally restricts the administration of opiates to physicians.

METHODS

In 2011 the medical directors of EMS in the German state of Rhineland- Palatinate (4 million inhabitants) developed and implemented a standard operating procedure (SOP) for paramedics related to the prehospital parenteral administration of paracetamol for patients with isolated limb trauma. After a 2 h training session and examination, paramedics were authorized to administer 1 g of paracetamol to patients with a pain score > 5 points on an 11-point numerical rating scale (NRS). For purposes of quality management, every administration of paracetamol had to be prospectively documented on a specific electronic mission form.

RESULTS

A total of 416 mission forms could be analyzed. After administration of paracetamol the median NRS score decreased from 8 points (interquartile range: 6; 8) to 4 points (interquartile range: 3; 7). In 51.2 % of the patients the pain intensity was reduced by at least 3 NRS points and in 50.5 % of the patients the NRS was less than 5 points after treatment. The extent of pain reduction was positively correlated with the initial NRS value (r = 0.31, p < 0.0001). No serious side effects were noted. The percentage of patients with an initial heart rate > 100/min declined from 14.6 % to 5.2 % after the administration of paracetamol (p < 0.0001), 18.7 % of the patients received paracetamol for trauma not related to the extremities and 7 % of the patients for nontraumatic pain. An emergency physician was involved in 50 % of the EMS missions and 98.6 % of the patients were transported to a hospital for further diagnostics and treatment.

CONCLUSION

The prehospital intravenous administration of paracetamol by paramedics to patients with limb trauma is simple, safe and in 50 % of the patients effective in achieving a NRS value < 5; however, further improvements in prehospital pain therapy initiated by paramedics are desirable, especially in patients with an initial NRS value > 7.

Single-dose systemic acetaminophen to prevent postoperative pain: a meta-analysis of randomized controlled trials

OBJECTIVES

The effect of a single-dose systemic acetaminophen to treat postoperative pain has been previously quantified, but the effect of systemic acetaminophen to prevent postoperative pain is currently not well defined. The preventive analgesic effect of acetaminophen has yet to be quantified in a meta-analysis. The objective of the current investigation was to evaluate the effect of a single preventive dose of systemic acetaminophen on postoperative pain outcomes.

MATERIALS AND METHODS

A wide search was performed to identify randomized controlled trials that evaluated the effects of a single dose of systemic acetaminophen on pain outcomes in a large variety of surgical procedures. Meta-analysis was performed using a random-effect model.

RESULTS

Eleven randomized clinical trials evaluating 740 patients were included in the analysis. The weighted mean difference (95% confidence interval [CI]) of the combined effects favored acetaminophen over control for early pain at rest (≤4 h, -1.1 (-2.0 to -0.2)) and early pain at movement (24 h, -1.9 (-2.8 to -1.0)) Postoperative opioid consumption was decreased in the systemic acetaminophen group compared with control. Weighted mean difference (95% CI) of -9.7 (-13.0 to -6.4) mg morphine intravenous equivalents systemic acetaminophen also reduced postoperative nausea and vomiting compared with control, odds ratio (95% CI) of 0.25 (0.13 to 0.47), numbers needed to treat (95% CI)=3.3 (2.3 to 5.9).

DISCUSSION

Systemic acetaminophen, when used as a single-dose preventive regimen, is an effective intervention to reduce postoperative pain. It also reduces postoperative nausea and/or vomiting. Doses >1 g were not associated with greater reduction in pain outcomes.

Metamizole-associated adverse events: a systematic review and meta-analysis

Background

Metamizole is used to treat pain in many parts of the world. Information on the safety profile of metamizole is scarce; no conclusive summary of the literature exists.

Objective

To determine whether metamizole is clinically safe compared to placebo and other analgesics.

Methods

We searched CENTRAL, MEDLINE, EMBASE, CINAHL, and several clinical trial registries. We screened the reference lists of included trials and previous systematic reviews. We included randomized controlled trials that compared the effects of metamizole, administered to adults in any form and for any indication, to other analgesics or to placebo. Two authors extracted data regarding trial design and size, indications for pain medication, patient characteristics, treatment regimens, and methodological characteristics. Adverse events (AEs), serious adverse events (SAEs), and dropouts were assessed. We conducted separate meta-analyses for each metamizole comparator, using standard inverse-variance random effects meta-analysis to pool the estimates across trials, reported as risk ratios (RRs). We calculated the DerSimonian and Laird variance estimate T² to measure heterogeneity between trials. The pre-specified primary end point was any AE during the trial period.

Results

Of the 696 potentially eligible trials, 79 trials including almost 4000 patients with short-term metamizole use of less than two weeks met our inclusion criteria. Fewer AEs were reported for metamizole compared to opioids, RR = 0.79 (confidence interval 0.79 to 0.96). We found no differences between metamizole and placebo, paracetamol and NSAIDs. Only a few SAEs were reported, with no difference between metamizole and other analgesics. No agranulocytosis or deaths were reported. Our results were limited by the mediocre overall quality of the reports.

Conclusion

For short-term use in the hospital setting, metamizole seems to be a safe choice when compared to other widely used analgesics. High-quality, adequately sized trials assessing the intermediate- and long-term safety of metamizole are needed.

Intravenous paracetamol as an antipyretic and analgesic medication: the significance of drug metabolism

One prospective, open-label, non-randomized study was conducted in 100 patients to define the antipyretic and analgesic effect of a new intravenous formulation of 1 g of paracetamol; 71 received paracetamol for the management of fever and 29 received paracetamol for pain relief after abdominal surgery or for neoplastic pain. Serial follow-up measurements of core temperature and of pain intensity were done for 6 h. Additional rescue medications were recorded for 5 days. Blood was sampled for the measurement of free paracetamol (APAP) and of glucuronide-APAP and N-sulfate-APAP by an HPLC assay. Defervescence, defined as core temperature below or equal to 37.1°C, was achieved in 52 patients (73.2%) within a median time of 3 h. Patients failing to become afebrile with the first dose of paracetamol became afebrile when administered other agents as rescue medications. Analgesia was achieved in 25 patients (86.4%) within a median time of 2 h. Serum levels of glucuronide-APAP were greater among non-responders to paracetamol. The presented results suggest that the intravenous formulation of paracetamol is clinically effective depending on drug metabolism.

Administration of paracetamol versus dipyrone by intravenous patient-controlled analgesia for postoperative pain relief in children after tonsillectomy

BACKGROUND AND OBJECTIVE

We compared the efficacy of intravenous (IV) paracetamol versus dipyrone via patient-controlled analgesia (PCA) for postoperative pain relief in children.

METHODS

The study was composed of 120 children who had undergone elective tonsillectomy after receiving general anesthesia. Patients were divided into 3 groups according to the dosage of postoperative intravenous-patient-controlled analgesia: paracetamol, dipyrone, or placebo. Pain was evaluated using a 0- to 100-mm visual analog scale and 1- to 4-pain relief score at 30 min, 1, 2, 4, 6, 12, and 24h postoperatively. Pethidine (0.25 mg kg(-1)) was administered intravenously to patients requiring rescue analgesia. Pethidine requirements were recorded during the first 24h postoperatively, and treatment related adverse effects were noted.

RESULTS

Postoperative visual analog scale scores were significantly lower with paracetamol group compared with placebo group at 6h (p<0.05), dipyrone group compared with placebo group at 30 min and 6h (p<0.05). No significant differences regarding visual analog scale values at 1, 2, 4, 12, and 24h were found. No significant differences were found between groups with respect to pain relief score (p>0.05). Postoperative pethidine requirements were significantly lower with paracetamol and dipyrone groups compared with placebo group (62.5%, 68.4% vs 90%, p<0.05). No significant differences were found between groups with respect to nausea, vomiting and the any other adverse effects of the drugs (p>0.05).

CONCLUSIONS

Paracetamol and dipyrone have well tolerability profile and effective analgesic properties when administered IV-PCA for postoperative analgesia in children after tonsillectomy.

Intravenous paracetamol and dipyrone for postoperative analgesia after day-case tonsillectomy in children: a prospective, randomized, double blind, placebo controlled study

Tonsillectomy is associated with severe postoperative pain for which, several drugs are employed for management.

Objective

In this double-blind, placebo-controlled study we aimed to evaluate the efficacy of intravenous paracetamol and dipyrone when used for post-tonsillectomy analgesia in children.

Method

120 children aged 3-6 yr, undergoing tonsillectomy with or without adenoidectomy and/ or ventilation tube insertion were randomized to receive intraoperative infusions of paracetamol (15 mg/kg), dipyrone (15 mg/kg) or placebo (0.9% NaCl). Evaluation was carried out at 0.25, 0.50, 1, 2, 4, 6h postoperatively. Pethidine 0.25 mg/kg was utilized as rescue analgesic. Cumulative pethidine requirement was the primary outcome. Pain intensity measurement, pain relief, sedation level, nausea and vomiting, postoperative bleeding and any other adverse effects were noted.

Results

No significant difference was found in pethidine requirement between paracetamol and dipyrone groups. Cumulative pethidine requirement was significantly less in paracetamol and dipyrone groups vs. placebo. No significant difference was observed between groups in postoperative pain intensity scores throughout the study.

Conclusion

Intravenous paracetamol is found to have a similar analgesic efficacy as intravenous dipyrone and they both help to reduce the opioid requirement for postoperative analgesia in pediatric day-case tonsillectomy.

Intravenous paracetamol for postoperative analgesia in laparoscopic cholecystectomy

BACKGROUND

Although opioids are the main choice for acute postoperative pain control, many side effects have been reported for them. NSAIDs and paracetamol have been used extensively as alternatives, and it seems that they are more effective for minor to moderate pain control postoperatively when have been used alone or in combination with opioids. As laparoscopic cholecystectomy poses moderate pain postoperatively, this study was planned to assess whether paracetamol is able to provide effective analgesia as a sole analgesic at least in the first few hours post operatively.

OBJECTIVES

We evaluated the effect of intravenous Paracetamol on postoperative pain in patients undergoing laparoscopic cholecystectomy.

PATIENTS AND METHODS

This is a randomized double- blind clinical trial study. 30 patients ASA class I, aged 18 to 50 years, candidate for laparoscopic cholecystectomy were recruited, and randomly divided into two equal groups. Group A (paracetamol group) received 1 gr paracetamol and group B received placebo ten minutes after the induction of anesthesia. 0.1 mg/Kg Morphine was administered intravenously based on patients compliant and pain score >3. Pain score and the opioids consumption were recorded in the first six hours postoperative. Patient's pain was measured by the VAS (Visual Analog Scale).

RESULTS

The pain score was lower in group A (P= 0.01), but the morphine consumption showed no significant difference between the groups (P= 0.24) during the first 6 hours postoperatively.

CONCLUSIONS

Although paracetamol (1gr) has caused a better pain relief quality but it is not a suitable analgesic for moderate pain control in acute phase after surgery alone.

Intravenous acetaminophen reduces postoperative nausea and vomiting: a systematic review and meta-analysis

Opioids are a key risk factor for postoperative nausea and vomiting (PONV). As intravenous (i.v.) acetaminophen reduces postoperative pain and opioid requirements, one would expect i.v. acetaminophen to be associated with a lower incidence of opioid-induced side effects, including PONV. We conducted a systematic search using Medline and Cochrane databases supplemented with hand search of abstract proceedings to identify randomized-controlled trials of i.v. acetaminophen. Inclusion criteria were (a) randomized for i.v. acetaminophen vs a placebo control, (b) general anesthesia, and (c) reported or obtainable PONV outcomes. Primary outcome was postoperative nausea and secondary outcome was postoperative vomiting. We included 30 studies with 2364 patients (1223 in the acetaminophen group, 1141 in the placebo group). The relative risk (95% confidence interval) was 0.73 (0.60-0.88) for nausea and 0.63 (0.45-0.88) for vomiting. Data showed significant heterogeneity for both nausea (P=0.02, I(2)=38%) and vomiting (P=0.006, I(2)=47%), but were homogeneous when studies were grouped according to timing of first administration: i.v. acetaminophen reduced nausea when given prophylactically either before surgery, 0.54 (0.40-0.74), or before arrival in the postanesthesia care unit, 0.67 (0.55-0.83); but not when given after the onset of pain, 1.12 (0.85-1.48). When i.v. acetaminophen was given prophylactically, the reduction of nausea correlated with the reduction of pain (odds ratio 0.66, 0.47-0.93), but not with reduction in postoperative opioids (odds ratio 0.89, 0.64-1.22). Prophylactically administered i.v. acetaminophen reduced PONV, mainly mediated through superior pain control.

Randomized, Double-Blind, Placebo-Controlled Study to Assess the Efficacy of Nonopioid Analgesics on Pain following Arthroscopic Knee Surgery

Purpose. In a randomized, double-blind trial, the efficacy of nonopioid analgesics on postoperative piritramide consumption was compared for pain relief during the first 24 h in patients recovering from arthroscopic knee surgery. Methods. 120 patients were treated with normal saline and/or one of the nonopioid analgesics (parecoxib, metamizole, paracetamol) in addition to piritramide using the PCA pump. Beginning in the postanesthesia care unit (PACU), patients were asked to quantify their pain experience at rest while piritramide consumption was recorded. Results. Piritramide consumption upon arrival in the PACU was high in all groups. However, cumulative consumption in the parecoxib group was significantly lower than that in the placebo group at 6 and 12 h after surgery. At discharge from the PACU, VAS scores dropped in all groups and were significantly lower in the parecoxib group. In the PACU, satisfaction of the patients was moderate and improved with time after surgery. Conclusions. There was statistically significant opioid-saving effect by administering parecoxib with better VAS scores and satisfaction level compared to placebo. The high pain score in the PACU in all groups immediately after recovering from remifentanil-based anesthesia would be prevented if local anesthetics were administered intra-articularly as part of a multimodal analgesic approach.

Acetaminophen Intravenous

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