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

Opioid versus non-opioid postoperative pain management in otolaryngology

BACKGROUND

The opioid epidemic in the United States has had devastating consequences, with many opioid-related deaths and a significant economic toll. Opioids have a significant role in postoperative pain management. Here we aim to analyze differences in postoperative opioid and non-opioid pain medications regimens following common otolaryngological surgeries between two large tertiary care medical centers: the Milton S. Hershey Medical Center, USA (HMC) and The Chaim Sheba Medical center, Israel (SMC).

METHODS

A retrospective chart review of patients undergoing common otolaryngological procedures during the years 2017-2019 was conducted at two tertiary care centers, one in the U.S. and the other in Israel. Types and doses of postoperative pain medications ordered and administered during admission were analyzed. Average doses ordered and administered in 24 h were calculated. Opioid medications were converted to a standardized unit of morphine milliequivalents (MME). Chi-square test and Wilcoxon rank-sum test were used to compare the groups.

RESULTS

The study included 204 patients (103 U.S., 101 Israel). Patient demographics were similar except for a longer length of stay in Israel (p < 0.01). In the U.S., 95% of patients were ordered opioids compared to 70% in Israel (P < 0.01). In the U.S., 68.9% of patients ordered opioids received the medications compared to 29.7% in Israel. The median opioid dose ordered in the U.S. was 45MME/24 h compared to 30MME/24 h in Israel (P < 0.01), while median dose received in the U.S. was 15MME/24 h compared to 3.8MME/24 h in Israel (P < 0.01). Opioid prescriptions at discharge were given to 92% of patients in the U.S. compared to 4% of patients in Israel (p < 0.01). A significantly higher number of patients in the U.S. were prescribed acetaminophen and ibuprofen (p < 0.0001). Dipyrone was prescribed to 78% of patients in Israel.

CONCLUSIONS

HMC demonstrated a significantly more permissive approach to both prescribing and consuming opioid medications for postoperative pain management than SMC for similar, common otolaryngological surgeries. Non-opioid alternatives and examining the cultural and medical practice-based differences contributing to the opioid epidemic should be discussed and reevaluated.

Dipyrone as pre-emptive measure in postoperative analgesia after tonsillectomy in children: a systematic review

INTRODUCTION

Tonsillectomy is the 2nd most common outpatient surgery performed on children in the United States of America. Its main complication is pain, which varies in intensity from moderate to severe. Dipyrone is one of the most widely used painkillers in the postoperative period in children. Its use, however, is controversial in the literature, to the point that it is banned in many countries due to its potential severe adverse effects. Because of this controversy, reviewing the analgesic use of dipyrone in the postoperative period of tonsillectomy in children is essential.

OBJECTIVE

The aim of this study was to review the analgesic use of dipyrone in the postoperative period of tonsillectomy in children.

METHODS

Systematic review of the literature, involving an evaluation of the quality of articles in the databases MEDLINE/Pubmed, EMBASE and Virtual Health Library, selected with a preestablished search strategy. Only studies with a randomised clinical trial design evaluating the use of dipyrone in the postoperative period of tonsillectomy in children were included.

RESULTS AND CONCLUSION

Only 2 randomised clinical trials were found. Both compared dipyrone, paracetamol, and placebo. We were unable to carry out a metanalysis because the studies were too heterogenous (dipyrone was used as pre-emptive analgesic in one and only postoperatively in another). The analgesic effect of dipyrone, measured by validated pain scales in childhood, was shown to be superior to placebo and similar to paracetamol. It appears that dipyrone exhibits a profile suitable for use in children. However, the scarcity of randomised clinical trials evaluating its analgesic effect in this age group leads to the conclusion that more well-designed studies are still needed to establish the role of dipyrone in the postoperative period of tonsillectomy in children.

PROSPECT guideline for tonsillectomy: systematic review and procedure-specific postoperative pain management recommendations

Tonsillectomy is one of the most frequently performed surgical procedures; however, pain management remains challenging. Procedure‐specific efficacy as well as specific risks of treatment options should guide selection of pain management protocols based on evidence and should optimise analgesia without harm. The aims of this systematic review were to evaluate the available literature and develop recommendations for optimal pain management after tonsillectomy. A systematic review utilising preferred reporting items for systematic reviews and meta‐analysis guidelines with procedure‐specific postoperative pain management (PROSPECT) methodology was undertaken. Randomised controlled trials published in the English language up to November 2019 assessing postoperative pain using analgesic, anaesthetic or surgical interventions were identified. Out of the 719 potentially eligible studies identified, 226 randomised controlled trials met the inclusion criteria, excluding the studies examining surgical techniques. Pre‐operative and intra‐operative interventions that improved postoperative pain were paracetamol; non‐steroidal anti‐inflammatory drugs; intravenous dexamethasone; ketamine (only assessed in children); gabapentinoids; dexmedetomidine; honey; and acupuncture. Inconsistent evidence was found for local anaesthetic infiltration; antibiotics; and magnesium sulphate. Limited evidence was found for clonidine. The analgesic regimen for tonsillectomy should include paracetamol; non‐steroidal anti‐inflammatory drugs; and intravenous dexamethasone, with opioids as rescue analgesics. Analgesic adjuncts such as intra‐operative and postoperative acupuncture as well as postoperative honey are also recommended. Ketamine (only for children); dexmedetomidine; or gabapentinoids may be considered when some of the first‐line analgesics are contra‐indicated. Further randomised controlled trials are required to define risk and combination of drugs most effective for postoperative pain relief after tonsillectomy.

Dose evaluation of intravenous metamizole (dipyrone) in infants and children: a prospective population pharmacokinetic study

PURPOSE

The prodrug metamizole is prescribed intravenously for postoperative pain in children, including off-label use in infants < 1 year. We aimed to assess the pharmacokinetics of the main metabolites of metamizole in children aged 3-72 months.

METHODS

A single dose of 10 mg/kg metamizole was administered intravenously for postoperative analgesia. Pharmacokinetic samples were drawn at predefined time points. Pharmacokinetics of the main active metabolite 4-methylaminoantipyrine and three other metabolites was characterized by both non-compartmental and population pharmacokinetic analysis. AUC_0-inf of 4-methylaminoantipyrine was calculated by non-compartmental analysis for two age cohorts (3-23 months, 2-6 years) and compared with the 80-125% range of adult dose-adjusted reference exposure (AUC_ref). Population pharmacokinetic analysis investigated age and weight dependency of the pharmacokinetics and optimal dosing strategies to achieve equivalent adult exposure.

RESULTS

A total of 25 children aged 5 months-5.8 years (7.8-24.8 kg) with at least one concentration sample were included; 19 children had ≥ 5 predefined samples up to 10 h after metamizole dose administration. AUC_0-inf of 4-methylaminoantipyrine in children 2-6 years was 29.9 mg/L/h (95% CI 23.4-38.2), significantly lower than AUC_ref (80-125% range 39.2-61.2 mg/L/h). AUC_0-inf of 4-methylaminoantipyrine in infants < 2 years was 43.6 mg/L/h (95% CI 15.8-119.0), comparable with AUC_ref, while infants < 12 months showed increased exposure. Observed variability could be partially explained by covariates weight and age.

CONCLUSIONS

Age-related changes in pharmacokinetics of 4-methylaminoantipyrine requires reduced weight-based IV dosing in infants < 1 year compared with infants and children up to 6 years (5 versus 10-20 mg/kg) to achieve equivalent adult exposure.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02660177 .

A Quality Improvement Initiative to Decrease Inappropriate Intravenous Acetaminophen Use at an Academic Medical Center

Background: Following availability in the United States in 2011, intravenous acetaminophen (IV APAP) was added to many hospital formularies for multimodal pain control. In 2014, the price of IV APAP increased from $12/g to $33/g and became a top 10 medication expenditure at our institution. Objective: To promote appropriate IV APAP prescribing and reduce costs. Design, Setting, Participants: Quality improvement project at a 562-bed academic medical center involving all inpatient admissions from 2010 to 2017. Interventions: Using Plan-Do-Study-Act (PDSA) methodology, our Pharmacy & Therapeutics (P&T) committee aimed to reduce inappropriate use of IV APAP by refinement of restriction criteria, development of clinical decision support in the electronic medical record, education of clinical staff on appropriate use, and empowerment of hospital pharmacists to enforce restrictions. Measurements: Monthly IV APAP utilization and spending were assessed using statistical process control charts. Balancing measures included monthly usage of IV opioid, IV ketorolac, and oral ibuprofen. Results: Five PDSA cycles were conducted during the study period. Monthly spending on IV APAP decreased from the highest average of $56 038 per month to $5822 per month at study conclusion. Interventions resulted in an 80% annual cost savings, or an approximate savings of $600 000 per year. Usage of IV opioids, IV ketorolac, and oral ibuprofen showed no major changes during the study period. Conclusions: IV APAP can be restricted in a safe and cost effective manner without concomitant increase in IV opioid use.

Tratamiento multimodal del dolor agudo postoperatorio agregando paracetamol IV a protocolo ya establecido

Introducción: El paracetamol intravenoso fue autorizado en el año 2001 para Europa, en el 2016 se autoriza en Guatemala. Esta presentación ha generado diferentes expectativas alrededor del mundo, por lo que se evaluó su administración al agregarse al tratamiento de analgesia postoperatoria multimodal. Objetivo: Evaluar el efecto analgésico en el tratamiento multimodal de dolor agudo postoperatorio con paracetamol IV en la población guatemalteca. Métodos: Estudio retrospectivo caso-control para la evaluación del dolor postoperatorio inmediato (24 horas) al agregar paracetamol IV al protocolo de analgesia estándar. En pacientes de ambos géneros, entre 18 y 70 años de edad, con peso mayor o igual a 50 Kg. con una cirugía electiva abierta o por vía laparoscópica, en una muestra de 110 pacientes dividida en dos grupos. Se comparó el número de pacientes que necesitaron dosis de rescate y el nivel de dolor según la Escala Visual Análoga (EVA) durante 4 evaluaciones en el postoperatorio agudo. Para determinar la correlación entre las variables se utilizó la prueba de independencia de Ji cuadrado. Resultados: Se demostró que agregar paracetamol IV al tratamiento estándar disminuye la cantidad de pacientes que requieren dosis de rescate y mejoran su analgesia durante el postoperatorio agudo. Conclusiones: El paracetamol IV es de beneficio al ser agregado al tratamiento de analgesia multimodal convencional de un hospital privado de Z.10. 

The Efficacy of Intravenous Magnesium Sulfate versus Intravenous Paracetamol on Children Posttonsillectomy Pain and Analgesic Requirement: A Randomized Controlled Study

Background:

One of the most common complications of tonsillectomy is pain, which leading to delayed recovery and later hospital discharge.

Aims:

We intended to compare the efficacy of magnesium sulfate versus paracetamol on the posttonsillectomy pain and analgesic requirement.

Settings and Design:

This study design was a prospective randomized controlled double-blinded clinical study.

Patients and Methods:

A total of 60 children with the American Society of Anesthesiologists physical status classes I and II, aged 3–12 years, scheduled for tonsillectomy were randomly divided into two groups each group contains 30 patients: (Group M): received an initial loading dose of magnesium sulfate 30 mg/kg over 15 min started with induction followed by continuous infusion of 10 mg/kg/h for 1 h regardless of the operation time and (Group P): received paracetamol infusion 10 mg/kg started with induction and continued for 1 h. Postoperatively, a blinded postanesthesia care unit (PACU) nurse observed the quality of analgesia using the face, legs, activity, cry, and consolability pain scores, bleeding, and sedation.

Statistical Analysis Used:

Student's t-test and Chi-square test were used for analysis.

Results:

Regarding postoperative pain, there was a statistically significant difference between the two groups at the time of admission in PACU (P = 0.025) as children who experienced pain already had taken rescue analgesic to alleviate pain. There was a statistically significant difference between the two groups regarding the need for analgesics (P = 0.038). There was no statistically significant difference regarding bleeding and sedation scores between the two study groups.

Conclusions:

Magnesium sulfate provided better postoperative analgesia and reduced need for analgesics after tonsillectomy compared to paracetamol, and regarding the incidence of bleeding and the degree of sedation the outcome in both groups was readily comparable.

The use of dipyrone (metamizol) as an analgesic in children: What is the evidence? A review

Dipyrone has analgesic, spasmolytic, and antipyretic effects and is used to treat pain. Due to a possible risk of agranulocytosis with the use of dipyrone, it has been banned in a number of countries. The most commonly used data for the use of dipyrone are related to adults. Information relating to the use of dipyrone in children is scarce. Given the potential added value of dipyrone in the treatment of pain, a review of the literature was conducted to obtain more insight into the analgesic efficacy of dipyrone in children as well as the safety of dipyrone in terms of adverse events. A literature search was done for original articles (in English, German, or Spanish language) which met the following criteria: the use of dipyrone for pain and children up to the age of 17 years old. All titles and abstracts retrieved were reviewed, independently, by two of the authors, for their suitability for inclusion. The references of the selected articles were also checked for additional relevant papers. The publications were categorized into case reports, observational studies, or randomized controlled trials. To assess the methodological quality of the studies, the Jadad score was used. In the limited available data, the analgesic efficacy of intravenous dipyrone appears similar to that of intravenous paracetamol. Evidence is lacking to support the claim that dipyrone is equivalent or even superior to Non-Steroid-Anti-Inflammatory-Drugs in pediatric pain. While the absolute risk of agranulocytosis with dipyrone in children, based on available literature, cannot be determined, case reports suggest that this risk is not negligible.

Randomized Prospective Evaluation of Intraoperative Intravenous Acetaminophen in Pediatric Adenotonsillectomy

Objective

To establish the safety and efficacy of single-dose intraoperative intravenous (IV) acetaminophen in postoperative pain management following adenotonsillectomy in addition to a standardized regimen of oral pain medication.

Study Design

Randomized, controlled prospective clinical trial.

Setting

Single academic medical center.

Subjects and Methods

Patients between the ages of 3 and 17 years scheduled for tonsillectomy or adenotonsillectomy by a single surgeon between December 2014 and November 2016 were recruited. Patients were randomly assigned to 1 of 2 groups; group 1 received a single intraoperative dose of IV acetaminophen, and group 2 did not. Induction and maintenance of anesthesia, as well as operative technique, were standardized. Nursing pain scores, pain medications administered, and recovery times were reviewed during the 24-hour postoperative period. Postoperative pain regimen included standing alternating oral acetaminophen and ibuprofen.

Results

In total, 260 patients were included in the study, and 131 (50.4%) received a single intraoperative dose of IV acetaminophen. Patients receiving IV acetaminophen were more likely to experience postoperative nausea and vomiting than patients who did not receive IV acetaminophen (1.53% vs 0.00%, P = .016). There were no significant differences noted for postoperative pain scores, requirements for breakthrough pain medications, time to discharge from the recovery room or hospital, or postoperative complications.

Conclusion

The use of a single intraoperative dose of IV acetaminophen was associated with minimal additional adverse effects. However, a single intraoperative IV dose of acetaminophen added to standard narcotic and nonnarcotic pain medication does not provide a statistically significant improvement in pain control.

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.

Immediate rescue designs in pediatric analgesic trials: a systematic review and meta-analysis

BACKGROUND

Designing analgesic clinical trials in pediatrics requires a balance between scientific, ethical, and practical concerns. A previous consensus group recommended immediate rescue designs using opioid sparing as a surrogate measure of analgesic efficacy. The authors summarize the performance of rescue analgesic designs in pediatric trials of four commonly used classes of analgesics: opioids, nonsteroidal antiinflammatory drugs, acetaminophen, and local anesthetics.

METHODS

MEDLINE, Embase, CINAHL, The Cochrane Library, and Web of science were searched in April 2013. The 85 studies selected were randomized or controlled clinical trials using immediate rescue paradigms in postoperative pain settings. A random-effects meta-analysis was used to synthesize predefined outcomes using Hedges' g. Difference between the means of the treatment arms were also expressed as a percentage of the corresponding value in the placebo group (placebo-treatment/placebo). Distributions of pain scores in study and control groups and relationships between opioid sparing and pain scores were examined.

RESULTS

For each of the four study drug classes, significant opioid sparing was demonstrated in a majority of studies by one or more of the following endpoints: (1) total dose (milligram per kilogram per hour), (2) percentage of children requiring rescue medication, and (3) time to first rescue medication (minutes). Pain scores averaged 2.4/10 in study groups, 3.4/10 in control groups.

CONCLUSIONS

Opioid sparing is a feasible pragmatic endpoint for pediatric pain analgesic trials. This review serves to guide future research in pediatric analgesia trials, which could test whether some specific design features may improve assay sensitivity while minimizing the risk of unrelieved pain.

Optical magnification devices in tonsillectomy: a prospective randomised clinical study

Tonsillectomy is one of the most common surgical procedure in otorhinolaryngology. A plethora of approaches has been undertaken so far to limit postoperative pain, one of the major problems patients are concerned with. Thermal damages of the surrounding tissue caused by coagulation during surgery are discussed to correlate with postoperative pain. Therefore, we studied whether the use of magnification devices reduced coagulation procedures and consequently limited post-operative pain. Following an intraindividual design, we performed tonsillectomy on one side using a microscope or magnifying glasses whereas the opposite side was operated with unsupported vision. As verified by a visual analogue scale, our study shows that neither the use of a microscope, nor the use of magnifying glasses leads to less post-operative pain. Other parameters like post-operative bleeding, duration of surgery, and total applied energy by bipolar coagulation were also comparable in the different treatment groups. Taken together, magnification-supported tonsillectomy does not seem to be appropriate for limiting complications of tonsillectomy, especially not for reducing post-operative pain.

Analgesic effectiveness of acetaminophen for primary cleft palate repair in young children: a randomized placebo controlled trial

BACKGROUND

Clefting of the lip, palate, or both is a common congenital abnormality. Inadequate treatment for pain in children may result from concerns over opioid-related adverse effects. Providing adequate pain control with minimal adverse effects remains challenging in children.

OBJECTIVES

To assess opioid-sparing effects of oral or intravenous acetaminophen following primary cleft palate repair in children.

METHODS

Prospective randomized controlled trial in 45 healthy children, ages 5 months to 5 years, using standardized general anesthesia and lidocaine infiltration of the operative field. Patients were allocated to groups: intravenous acetaminophen/oral placebo (intravenous), oral acetaminophen/intravenous placebo (oral), or intravenous/oral placebo (control). Groups were compared for differences in opioid administration during the 24-h study period (morphine equivalents µg·kg(-1) ; 95% confidence interval).

RESULTS

Intravenous acetaminophen decreased opioid requirement after surgery (P = 0.003). Patients in the intravenous group received less opioid (272.9; 202.9-342.8 µg·kg(-1) ) than control patients (454.2; 384.3-524.2 µg·kg(-1) ; P < 0.002). Opioid requirement in oral patients (376.5; 304.1-448.9 µg·kg(-1) ) was intermediate and not significantly different from either intravenous (P = 0.11) or control (P = 0.27). During the ward phase of care, intravenous had better analgesia than control (P = 0.002), and both intravenous and oral group patients received less opioid than control (P = 0.01).

CONCLUSION

Intravenous acetaminophen given to young children undergoing primary cleft palate repair was associated with opioid-sparing effects compared to placebo. The fewer morphine doses during ward stay in both intravenous and oral may be important clinically in some settings.

Cost-effectiveness of intravenous acetaminophen for pediatric tonsillectomy

OBJECTIVE

The primary outcome of this study was to examine the cost-effectiveness of the intraoperative combination of intravenous (IV) acetaminophen and IV opioids, versus IV opioids alone, as a part of an inhalational anesthetic technique for tonsillectomy in children.

METHODS

We used Decision Maker® software to construct and analyze a decision analytic model. Base-case and sensitivity analyses were performed. We studied the use of rescue analgesics in the postanesthesia care unit (PACU), adverse effects of acetaminophen and opioids, and costs associated with adverse effects. Costs were in 2013 US dollars, and effectiveness was measured as frequency of avoiding the need for rescue analgesics. Direct medical costs included medication, equipment, supplies, and labor associated with the treatment of adverse events from pain medications. Medication costs assumed single-dose vials.

RESULTS

In the base case, IV acetaminophen in combination with opioids was both less costly ($17.12) and more effective (3.3% fewer rescue events). In sensitivity analyses, the combination strategy remained cost-effective as long as the frequency of rescue analgesic administration was less than that in the opioid-alone strategy. Although medication costs of the combination strategy were higher, the overall costs were less than the competing strategy due to reduced adverse effects and reduced time spent in PACU.

CONCLUSIONS

The routine use of IV acetaminophen as an adjuvant to IV opioids for tonsillectomy with or without adenoidectomy in children aged <17 years should be considered as a means to reduce the need for rescue analgesia and in turn reduce costs.