Early bioavailability of paracetamol after oral or intravenous administration

Clinical chorioamnionitis at term: definition, pathogenesis, microbiology, diagnosis, and treatment

Clinical chorioamnionitis, the most common infection-related diagnosis in labor and delivery units, is an antecedent of puerperal infection and neonatal sepsis. The condition is suspected when intrapartum fever is associated with two other maternal and fetal signs of local or systemic inflammation (eg, maternal tachycardia, uterine tenderness, maternal leukocytosis, malodorous vaginal discharge or amniotic fluid, and fetal tachycardia). Clinical chorioamnionitis is a syndrome caused by intraamniotic infection, sterile intraamniotic inflammation (inflammation without bacteria), or systemic maternal inflammation induced by epidural analgesia. In cases of uncertainty, a definitive diagnosis can be made by analyzing amniotic fluid with methods to detect bacteria (Gram stain, culture, or microbial nucleic acid) and inflammation (white blood cell count, glucose concentration, interleukin-6, interleukin-8, matrix metalloproteinase-8). The most common microorganisms are Ureaplasma species, and polymicrobial infections occur in 70% of cases. The fetal attack rate is low, and the rate of positive neonatal blood cultures ranges between 0.2% and 4%. Intrapartum antibiotic administration is the standard treatment to reduce neonatal sepsis. Treatment with ampicillin and gentamicin have been recommended by professional societies, although other antibiotic regimens, eg, cephalosporins, have been used. Given the importance of Ureaplasma species as a cause of intraamniotic infection, consideration needs to be given to the administration of antimicrobial agents effective against these microorganisms such as azithromycin or clarithromycin. We have used the combination of ceftriaxone, clarithromycin, and metronidazole, which has been shown to eradicate intraamniotic infection with microbiologic studies. Routine testing of neonates born to affected mothers for genital mycoplasmas could improve the detection of neonatal sepsis. Clinical chorioamnionitis is associated with decreased uterine activity, failure to progress in labor, and postpartum hemorrhage; however, clinical chorioamnionitis by itself is not an indication for cesarean delivery. Oxytocin is often administered for labor augmentation, and it is prudent to have uterotonic agents at hand to manage postpartum hemorrhage. Infants born to mothers with clinical chorioamnionitis near term are at risk for early-onset neonatal sepsis and for long-term disability such as cerebral palsy. A frontier is the noninvasive assessment of amniotic fluid to diagnose intraamniotic inflammation with a transcervical amniotic fluid collector and a rapid bedside test for IL-8 for patients with ruptured membranes. This approach promises to improve diagnostic accuracy and to provide a basis for antimicrobial administration.

Unlocking the Optimal Analgesic Potential: A Systematic Review and Meta-Analysis Comparing Intravenous, Oral, and Rectal Paracetamol in Equivalent Doses

Paracetamol (acetaminophen) is an extensively used analgesic for acute and chronic pain management. Currently, paracetamol is manufactured for oral, rectal, and intravenous (IV) use. Research has shown varied results on the analgesic properties of IV paracetamol compared to oral and rectal paracetamol; however, research on the same doses of paracetamol is limited. Therefore, this review was constructed to explore the analgesic properties of IV paracetamol compared with oral and rectal paracetamol administered in equivalent doses. A broad and thorough literature search was performed on five electronic databases, including PubMed, ScienceDirect, Medline, Scopus, and Google Scholar. Statistical analysis of all outcomes in our review was then performed using the Review Manager software. Outcomes were categorized as primary (pain relief and time to request rescue analgesia) and secondary (adverse events after analgesia). An extensive quality appraisal was also done using the Review Manager software's Cochrane risk of bias tool. The literature survey yielded 2,945 articles, of which 12 were used for review and analysis. The pooled analysis for patients undergoing surgical procedures showed that IV paracetamol had statistically similar postoperative pain scores at two (mean difference (MD) = -0.14; 95% confidence interval (CI) -0.58-0.29; p = 0.51), 24 (MD = 0.09; 95% CI = -0.02-0.21; p = 0.12), and 48 (MD = 0.04; 95% CI = -0.08-0.16; p = 0.52) hours as oral paracetamol. Similarly, the data on time to rescue analgesia showed no considerable difference between the IV and oral paracetamol groups (MD = -1.58; 95% CI = -5.51-2.35; p = 0.43). On the other hand, the pooled analysis for patients presenting non-surgical acute pain showed no significant difference in the mean pain scores between patients treated with IV and oral paracetamol (MD = -0.35; 95% CI = -2.19-1.48; p = 0.71). Furthermore, a subgroup analysis of analgesia-related adverse events showed that the incidences of vomiting/nausea and pruritus did not differ between patients receiving IV and oral paracetamol (odds ratio (OR) = 0.71; 95% CI = 0.45-1.11; p = 0.13 and OR = 0.48; 95% CI = 0.18-1.29; p = 0.05, respectively). A review of information from two trials comparing equal doses of IV and rectal paracetamol suggested that the postoperative pain scores were statistically similar between the groups. IV paracetamol is not superior to oral or rectal paracetamol administered in equal doses. Therefore, we cannot recommend or refute IV paracetamol as the first-line analgesia for acute and postoperative pain.

Practice Advisory for Preoperative and Intraoperative Pain Management of Cardiac Surgical Patients: Part 2

Pain after cardiac surgery is of moderate to severe intensity, which increases postoperative distress and health care costs, and affects functional recovery. Opioids have been central agents in treating pain after cardiac surgery for decades. The use of multimodal analgesic strategies can promote effective postoperative pain control and help mitigate opioid exposure. This Practice Advisory is part of a series developed by the Society of Cardiovascular Anesthesiologists (SCA) Quality, Safety, and Leadership (QSL) Committee's Opioid Working Group. It is a systematic review of existing literature for various interventions related to the preoperative and intraoperative pain management of cardiac surgical patients. This Practice Advisory provides recommendations for providers caring for patients undergoing cardiac surgery. This entails developing customized pain management strategies for patients, including preoperative patient evaluation, pain management, and opioid use-focused education as well as perioperative use of multimodal analgesics and regional techniques for various cardiac surgical procedures. The literature related to this field is emerging, and future studies will provide additional guidance on ways to improve clinically meaningful patient outcomes.

The Three W's of Acetaminophen In Children: Who, Why, and Which Administration Mode

Acetaminophen is one of the oldest medications commonly administered in children. Its efficacy in treating fever and pain is well accepted among clinicians. However, the available evidence supporting the use of acetaminophen's different modes of administration remains relatively scarce and poorly known. This short report summarizes the available evidence and provides a framework to guide clinicians regarding a rational use of acetaminophen in children.

Intravenous acetaminophen for postoperative pain control after open abdominal and thoracic surgery in pediatric patients: a systematic review and meta-analysis

Pediatric opioid exposure increases short- and long-term adverse events (AE). The addition of intravenous acetaminophen (IVA) to pediatric pain regimes to may reduce opioids but is not well studied postoperatively. Our objective was to quantify the impact of IVA on postoperative pain, opioid use, and AEs in pediatric patients after major abdominal and thoracic surgery. Medline, Embase, CINAHL, Web of Science, and Cochrane Library were searched systematically for randomized controlled trials (RCTs) comparing IVA to other modalities. Five RCTs enrolling 443 patients with an average age of 2.12 years (± 2.81) were included. Trials comparing IVA with opioids to opioids alone were meta-analyzed. Low to very low-quality evidence demonstrated equivalent pain scores between the groups (-0.23, 95% CI -0.88 to 0.40, p 0.47) and a reduction in opioid consumption (-1.95 morphine equivalents/kg/48 h, 95% CI -3.95 to 0.05, p 0.06) and minor AEs (relative risk 0.39, 95% CI 0.11 to 1.43, p 0.15). We conclude that the addition of IVA to opioid-based regimes in pediatric patients may reduce opioid use and minor AEs without increasing postoperative pain. Given the certainty of evidence, further research featuring patient-important outcomes and prolonged follow-up is necessary to confirm these findings.

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.

Current State of Analgesia and Sedation in the Pediatric Intensive Care Unit

Critically ill pediatric patients often require complex medical procedures as well as invasive testing and monitoring which tend to be painful and anxiety-provoking, necessitating the provision of analgesia and sedation to reduce stress response. Achieving the optimal combination of adequate analgesia and appropriate sedation can be quite challenging in a patient population with a wide spectrum of ages, sizes, and developmental stages. The added complexities of critical illness in the pediatric population such as evolving pathophysiology, impaired organ function, as well as altered pharmacodynamics and pharmacokinetics must be considered. Undersedation leaves patients at risk of physical and psychological stress which may have significant long term consequences. Oversedation, on the other hand, leaves the patient at risk of needing prolonged respiratory, specifically mechanical ventilator, support, prolonged ICU stay and hospital admission, and higher risk of untoward effects of analgosedative agents. Both undersedation and oversedation put critically ill pediatric patients at high risk of developing PICU-acquired complications (PACs) like delirium, withdrawal syndrome, neuromuscular atrophy and weakness, post-traumatic stress disorder, and poor rehabilitation. Optimal analgesia and sedation is dependent on continuous patient assessment with appropriately validated tools that help guide the titration of analgosedative agents to effect. Bundled interventions that emphasize minimizing benzodiazepines, screening for delirium frequently, avoiding physical and chemical restraints thereby allowing for greater mobility, and promoting adequate and proper sleep will disrupt the PICU culture of immobility and reduce the incidence of PACs.

Effect of Intravenous Acetaminophen on Mean Arterial Blood Pressure: A Post Hoc Analysis of the EFfect of Intravenous ACetaminophen on PosToperative HypOxemia After Abdominal SurgeRy Trial

BACKGROUND

Acetaminophen is commonly used as part of multimodal analgesia for acute pain. The intravenous formulation offers a more predictable bioavailability compared to oral and rectal acetaminophen. There have been reports of hypotension with intravenous acetaminophen attributable to centrally mediated and vasodilatory effects. We tested the hypothesis that in adults having abdominal surgery the use of intravenous acetaminophen versus placebo for postoperative pain management is associated with a decrease in mean arterial pressure (MAP) after its administration.

METHODS

This is a substudy of eFfect of intravenous ACetaminophen on posToperative hypOxemia after abdominal surgeRy (FACTOR) trial (NCT02156154). FACTOR trial randomly assigned adults undergoing abdominal surgery to either 1 g of acetaminophen or placebo every 6 hours during the first postoperative 48 hours. Continuous monitoring of blood pressure was obtained by noninvasive ViSi Mobile device (Sotera Wireless, Inc, San Diego, CA) at 15-second intervals during initial 48 hours postoperatively. We excluded patients without continuous monitoring data available. The primary outcome was the MAP difference between MAP 5 minutes before study drug administration (baseline) and MAP 30 minutes poststudy drug administration initiation. We used a linear mixed effects model to assess the treatment effect on MAP change. The secondary outcome was MAP area under baseline (AUB) during the 30 minutes after treatment. In a sensitivity analysis of change in MAP from predrug to postdrug administration, we instead used postdrug MAP as the outcome adjusting for the baseline MAP in the model.

RESULTS

Among 358 patients analyzed, 182 received acetaminophen and 176 placebo. The mean (standard deviation [SD]) of average MAP change was -0.75 (5.9) mm Hg for the treatment and 0.32 (6.3) mm Hg for the placebo. Acetaminophen was found to decrease the MAP from baseline more than placebo after drug administration. The estimated difference in mean change of MAP was -1.03 (95% confidence interval [CI] -1.60 to -0.47) mm Hg; P < .001. The sensitivity analysis showed postoperative MAP in the acetaminophen group was 1.33 (95% CI, 0.76-1.90) mm Hg lower than in the placebo group (P < .001). The median of MAP AUB was 33 [Q1 = 3.3, Q3 = 109] mm Hg × minutes for the treatment and 23 [1.6, 79] mm Hg × minutes for the placebo. Acetaminophen was found to increase the AUB with an estimated median difference of 15 (95% CI, 5-25) mm Hg × minutes (P = .003).

CONCLUSIONS

Intravenous acetaminophen decreases MAP after its administration. However, this decrease does not appear to be clinically meaningful. Clinicians should not refrain to use intravenous acetaminophen for acute pain management because of worries of hypotension.

Intravenous versus oral paracetamol for postoperative analgesia: A systematic review

Paracetamol is a widely used analgesic agent that can be given by several different routes of administration. In the surgical setting, intravenous infusions of paracetamol are used, but an alternative is using oral paracetamol as a premedication. This systematic review is the first to compare the relative efficacy of intravenous and oral paracetamol at providing postoperative analgesia. Nine relevant studies were identified. Intravenous paracetamol resulted in a postoperative pain score of 0.5 points lower than in those receiving oral paracetamol premedication. Patients receiving intravenous paracetamol also had a small reduction in postoperative opioid requirements, but the time at which rescue analgesia was required did not differ. These results suggest that intravenous paracetamol may offer a small advantage over oral paracetamol premedication at providing postoperative analgesia.

Management of clinical chorioamnionitis: an evidence-based approach

This review aimed to examine the existing evidence about interventions proposed for the treatment of clinical chorioamnionitis, with the goal of developing an evidence-based contemporary approach for the management of this condition. Most trials that assessed the use of antibiotics in clinical chorioamnionitis included patients with a gestational age of ≥34 weeks and in labor. The first-line antimicrobial regimen for the treatment of clinical chorioamnionitis is ampicillin combined with gentamicin, which should be initiated during the intrapartum period. In the event of a cesarean delivery, patients should receive clindamycin at the time of umbilical cord clamping. The administration of additional antibiotic therapy does not appear to be necessary after vaginal or cesarean delivery. However, if postdelivery antibiotics are prescribed, there is support for the administration of an additional dose. Patients can receive antipyretic agents, mainly acetaminophen, even though there is no clear evidence of their benefits. Current evidence suggests that the administration of antenatal corticosteroids for fetal lung maturation and of magnesium sulfate for fetal neuroprotection to patients with clinical chorioamnionitis between 24 0/7 and 33 6/7 weeks of gestation, and possibly between 23 0/7 and 23 6/7 weeks of gestation, has an overall beneficial effect on the infant. However, delivery should not be delayed to complete the full course of corticosteroids and magnesium sulfate. Once the diagnosis of clinical chorioamnionitis has been established, delivery should be considered, regardless of the gestational age. Vaginal delivery is the safer option and cesarean delivery should be reserved for standard obstetrical indications. The time interval between the diagnosis of clinical chorioamnionitis and delivery is not related to most adverse maternal and neonatal outcomes. Patients may require a higher dose of oxytocin to achieve adequate uterine activity or greater uterine activity to effect a given change in cervical dilation. The benefit of using continuous electronic fetal heart rate monitoring in these patients is unclear. We identified the following promising interventions for the management of clinical chorioamnionitis: (1) an antibiotic regimen including ceftriaxone, clarithromycin, and metronidazole that provides coverage against the most commonly identified microorganisms in patients with clinical chorioamnionitis; (2) vaginal cleansing with antiseptic solutions before cesarean delivery with the aim of decreasing the risk of endometritis and, possibly, postoperative wound infection; and (3) antenatal administration of N-acetylcysteine, an antioxidant and antiinflammatory agent, to reduce neonatal morbidity and mortality. Well-powered randomized controlled trials are needed to assess these interventions in patients with clinical chorioamnionitis.

A systematic review and trial sequential analysis of intravenous vs. oral peri-operative paracetamol

Postoperative pain might be different after intravenous vs. oral paracetamol. We systematically reviewed randomised controlled trials in patients >15 years that compared intravenous with oral paracetamol for postoperative pain. We identified 14 trials with 1695 participants. There was inconclusive evidence for an effect of route of paracetamol administration on postoperative pain at 0–2 h (734 participants), 2–6 h (766 participants), 6–24 h (1115 participants) and >24 h (248 participants), with differences in standardised mean (95%CI) pain scores for intravenous vs. oral of −0.17 (−0.45 to 0.10), −0.09 (−0.24 to 0.06), 0.06 (−0.12 to 0.23) and 0.03 (−0.22 to 0.28), respectively. Trial sequential analyses suggested that a total of 3948 participants would be needed to demonstrate a meaningful difference in pain or its absence at 0–2 h. There were no differences in secondary outcomes. Intravenous paracetamol is more expensive than oral paracetamol. Substitution of oral paracetamol in half the patients given intravenous paracetamol in our hospital would save around £ 38,711 (€ 43,960 or US$ 47,498) per annum.

Effect of intravenous acetaminophen versus fentanyl on postoperative pain after transurethral lithotripsy

Background

Postoperative pain is the most common postoperative complication. This study was conducted to assess the effect of acetaminophen versus fentanyl on postoperative pain relief in patients who underwent urologic surgeries.

Methods

This clinical trial was conducted on patients aged 18–65 years. Patients were randomly assigned to receive either 2000 mg acetaminophen (propacetamol) or 2 mcg.kg⁻¹ fentanyl intravenously, 15 min before the end of surgery. The postoperative pain was evaluated every 6 h for 24 h using the Visual Analog Scale. Total morphine dose taken in 24 h and hemodynamic status were evaluated.

Results

Eighty patients were enrolled into the trial. The mean score of pain in 6, 12, 18, and 24 h after surgery was lower in the acetaminophen group than in the fentanyl group but the difference was not statistically significant except in 12 and 18 h after surgery (p < 0.05). The amount of administered morphine was higher in the fentanyl group than in the acetaminophen group, but the difference was not statistically significant. The hemodynamic status including systolic and diastolic blood pressure and heart rates were nearly the same in the two groups but the SpO₂ mean was significantly higher in the acetaminophen group than the fentanyl group.

Conclusions

This trial indicated that intravenous acetaminophen is as effective as intravenous fentanyl in pain relief after urologic surgeries (transurethral lithotripsy).

Introduction and Audit of Intravenous Paracetamol at a Tertiary Paediatric Teaching Hospital

Although intravenous (IV) paracetamol is an attractive analgesic, there is little information on its paediatric use. During an introduction phase with limited prescribing rights, an audit was performed to assess its use and cost impact at a tertiary paediatric centre. Patients receiving IV paracetamol prescribed by two pain specialists for restricted indications had their medical records retrospectively reviewed for age, weight, diagnosis, indications/dose for IV (and other route) paracetamol/other analgesics/antiemetics, vomiting/oral intake and liver function tests if performed. One-hundred-and-twenty-one children and five neonates received 1216 (median 8 each) doses of paracetamol IV. Audited expenditure for IV paracetamol was 3.9 times the rectal alternative ($3435 vs. $875). Indications were appropriate, with 97% of patients nil oral, 41% vomiting, 17% having rectal route replaced and 3% avoiding parenteral morphine. Only five patients received incorrect dosing: three through prescription errors and two as guideline deviations; none were considered dangerous. No liver function test derangements could be directly attributed to paracetamol.

This data facilitated our application to extend prescribing rights for IV paracetamol within our institution. As there is limited information or local experience with the use of IVparacetamol in paediatric settings in Australia, our data may be of use to other centres considering the introduction of the IV form of this agent.

Assessment and Early Management of Pain in Hip Fractures: The Impact of Paracetamol

Introduction

As the number of patients sustaining hip fractures increases, interventions aimed at improving patient comfort and reducing complication burden acquire increased importance. Frailty, cognitive impairment, and difficulty in assessing pain control characterize this population. In order to inform future care, a review of pain assessment and the use of preoperative intravenous paracetamol (IVP) is presented.

Materials and Methods

Systematic review of preoperative IVP administration in patients presenting with a hip fracture.

Results

Intravenous paracetamol is effective in the early management of pain control in the hip fracture population. There is a considerable decrease in use of breakthrough pain medications when compared with other pain relief modalities. Additionally, IVP reduces the incidence of opioid-induced complications, reduces length of stay, and lowers mean pain scores. Another significant finding of this study is the poor administration of all analgesics to patients with hip fracture with up to 72% receiving no prehospital analgesia.

Discussion

The potential benefits of IVP as routine in the early management of hip fracture-related pain are clear. Studies of direct comparison between analgesia regimes to inform optimum bundles of analgesic care are sparse. This study highlights the need for properly constructed pathway-driven comparator studies of contemporary analgesia regimes, with IVP as a central feature to optimize pain control and minimize analgesia-related morbidity in this vulnerable population.

The antipyretic efficacy and safety of propacetamol compared with dexibuprofen in febrile children: a multicenter, randomized, double-blind, comparative, phase 3 clinical trial

BACKGROUND

We aimed to compare the antipyretic efficacy, safety, and tolerability between oral dexibuprofen and intravenous propacetamol in children with upper respiratory tract infection (URTI) presenting with fever.

METHODS

Patients aging from 6 months to 14 years admitted for URTI with axillary body temperature ≥ 38.0 °C were enrolled and randomized into the study or control group. Patients in the study group were intravenously infused with propacetamol and subsequently oral placebo medication was administered. Patients in the control group were intravenously infused with 100 mL of 0.9% sodium chloride solution without propacetamol and then oral dexibuprofen was administered. We checked the body temperature of all patients at 0.5 h (hr), 1 h, 1.5 h, 2 h, 3 h, 4 h, and 6 h after oral placebo or dexibuprofen had been applied.

RESULTS

A total of 263 patients (125 in the study group) were finally enrolled. The body temperatures of patients in the study group were significantly lower until 2 h after administration (37.73 ± 0.58 vs 38.36 ± 0.69 °C (p < 0.001), 37.37 ± 0.53 vs 37.88 ± 0.69 °C (p < 0.001), 37.27 ± 0.60 vs 37.62 ± 0.66 °C (p < 0.001), 37.25 ± 0.62 vs 37.40 ± 0.60 °C (p = 0.0452), at 0.5 h, 1 h, 1.5 h, and 2 h, respectively). The two groups showed no significant differences in terms of the range of body temperature decrease, the Area Under the Curve of body temperature change for antipyretic administration-and-time relationship, the maximum value of body temperature decrease during the 6 h test period, the number of patients whose body temperature normalized (< 37.0 °C), the mean time when first normalization of body temperature, and the development of adverse events including gastrointestinal problem, elevated liver enzyme, and thrombocytopenia.

CONCLUSIONS

Intravenous propacetamol may be a safe and effective choice for pediatric URTI patients presenting with fever who are not able to take oral medications or need faster fever control.

TRIAL REGISTRATION

CRIS KCT0002888 . Date of registration: July 31st, 2013.

Postoperative pain management in children: Guidance from the pain committee of the European Society for Paediatric Anaesthesiology (ESPA Pain Management Ladder Initiative)

The main remit of the European Society for Paediatric Anaesthesiology (ESPA) Pain Committee is to improve the quality of pain management in children. The ESPA Pain Management Ladder is a clinical practice advisory based upon expert consensus to help to ensure a basic standard of perioperative pain management for all children. Further steps are suggested to improve pain management once a basic standard has been achieved. The guidance is grouped by the type of surgical procedure and layered to suggest basic, intermediate, and advanced pain management methods. The committee members are aware that there are marked differences in financial and personal resources in different institutions and countries and also considerable variations in the availability of analgesic drugs across Europe. We recommend that the guidance should be used as a framework to guide best practice.

Comparative Plasma and Cerebrospinal Fluid Pharmacokinetics of Paracetamol After Intravenous and Oral Administration

BACKGROUND

We compared plasma and cerebrospinal fluid (CSF) pharmacokinetics of paracetamol after intravenous (IV) and oral administration to determine dosing regimens that optimize CSF concentrations.

METHODS

Twenty-one adult patients were assigned randomly to 1 g IV, 1 g oral or 1.5 g oral paracetamol. An IV cannula and lumbar intrathecal catheter were used to sample venous blood and CSF, respectively, over 6 hours. The plasma and CSF maximum concentrations (Cmax), times to maximum concentrations (Tmax), and area under the plasma and CSF concentration-time curves (AUCs) were calculated using noncompartmental techniques. Significance was defined by P < .0167 (Bonferroni correction for 3 comparisons for each parameter). Probability (X < Y) (p″) with Bonferroni corrected 95% confidence intervals (CIs) were calculated (CIs including 0.5 meet the null hypothesis). Results are presented as median (range) or p″ (CI). P values are listed as 1 g IV vs 1 g orally, 1 g IV vs 1.5 g orally and 1 g orally vs 1.5 g orally, respectively.

RESULTS

Wide variation in measured paracetamol concentrations was observed, especially in the oral groups. The median plasma Cmax in the 1 g IV group was significantly greater than the oral groups. In contrast, the median CSF Cmax was not different between groups. The median plasma Tmax in the 1 g IV group was 105 and 75 minutes earlier than in the 1 and 1.5 g oral groups. The median CSF Tmax was not significantly different between groups. The median plasma AUC (total) was not significantly different between groups; however, in the first hour, the median plasma AUC was significantly greater in the IV group than in the oral groups. In the second hour, there was no difference between groups. The median CSF AUC (total) did not significantly differ between groups; however, in the first hour, the median CSF AUC was significantly greater in the IV compared with the orally groups. In the second hour, there was no difference between groups. Our analysis indicated that the median Cmax, Tmax, and AUC values lacked precision because of small sample sizes.

CONCLUSIONS

Peak plasma concentrations were greater and reached earlier after IV than oral dosing. Evidence for differences in CSF Cmax and Tmax was lacking because of the small size of this study.

Acetaminophen, nonsteroidal anti-inflammatory drugs, and cyclooxygenase-2 selective inhibitors: an update

SUMMARY

Plastic and cosmetic surgery is often performed as an ambulatory procedure, and pain is often mild to moderate. Good pain relief is central to patient comfort and satisfaction. Analgesics used should ensure rapid onset and adequate pain relief lasting a sufficiently long duration with minimal or no side effects. Acetaminophen is well tolerated by patients, efficacious, and associated with only minor side effects, when used in the minimal effective doses. Nonsteroidal anti-inflammatory drugs (NSAIDs) are more efficacious, having lower numbers needed to treat compared with acetaminophen, but have several side effects and contraindications. However, when used in the correct doses in healthy patients, NSAIDs are excellent for pain management with one caveat that there is an increased risk for oozing or bleeding. In contrast, cyclooxygenase inhibitors (Coxibs) are equally efficacious as NSAIDs but have the added advantage that they have minimal or no effect on platelet function, and therefore, the risk for bleeding complications is minimal. However, there has been some concern about the risk of vascular events in patients with ischemic heart disease, specifically when using Coxibs, but even some NSAIDs, for example, diclofenac. In conclusion, acetaminophen should be given postoperatively to all patients undergoing plastic surgical procedures. For patients undergoing moderately invasive surgery, the addition of Coxibs to acetaminophen would be an advantage except in the patient with ischemic heart disease where NSAIDs could have a place in management of pain. Side effects and contraindications of NSAIDs, however, restrict their use to the healthy patient with mild comorbidities.

Evaluation of a protocol-based intervention to promote timely switching from intravenous to oral paracetamol for post-operative pain management: an interrupted time series analysis

RATIONALE, AIMS AND OBJECTIVES

Timely switching from intravenous to oral therapy ensures optimized treatment and efficient use of health care resources. Intravenous (IV) paracetamol is widely used for post-operative pain management but not always switched to the oral form in a timely manner, leading to unnecessary increase in expenditure. This study aims to evaluate the impact of a multifaceted intervention to promote timely switching from the IV to oral form in the post-operative setting.

METHODS

An evidence-based prescribing protocol was designed and implemented by the clinical pharmacy team in a single district general hospital in Egypt. The protocol specified the criteria for appropriate prescribing of IV paracetamol. Doctors were provided with information and educational sessions prior to implementation. A prospective, quasi-experimental study was undertaken to evaluate its impact on IV paracetamol utilization and costs. Data on monthly utilization and costs were recorded for 12 months before and after implementation (January 2012 to December 2013). Data were analysed using interrupted time series analysis.

RESULTS

Prior to implementation, in 2012, total spending on IV paracetamol was 674 154.00 Egyptian Pounds (L.E.) ($23,668.00). There was a non-significant (P > 0.05) downward trend in utilization (-32 ampoules per month) and costs [reduction of 632 L.E. ($222) per month]. Following implementation, immediate decrease in utilization and costs (P < 0.05) and a trend change over the follow-up period were observed. Average monthly reduction was 26% (95% CI: 24% to 28%, P < 0.001).

CONCLUSION

A multifaceted, protocol-based intervention to ensure timely switching from IV-to-oral paracetamol achieved significant reduction in utilization and cost of IV paracetamol in the first 5 months of its implementation.

IV acetaminophen: Efficacy of a single dose for postoperative pain after hip arthroplasty: subset data analysis of 2 unpublished randomized clinical trials

Inadequate control of postoperative pain after orthopedic procedures may trigger complications that increase morbidity. Multimodal analgesia is used to manage pain effectively after surgical procedures and reduce the need for rescue analgesia. Intravenous (IV) acetaminophen (OFIRMEV; Cadence Pharmaceuticals, Inc.), an analgesic that has been studied and used in the multimodal management of acute pain after major orthopedic procedures, combines the safety seen with oral and rectal formulations with a preferred route of administration. Two double-blind, randomized, placebo-controlled clinical trials were conducted (total 130 patients) to determine the efficacy and safety of single-dose IV acetaminophen in patients following total hip arthroplasty. Although both studies were stopped prematurely, overlap in patient populations, study design, and methodologies in the single-dose phase of these studies allowed for analysis of their results to be presented concurrently. Both trials demonstrated IV acetaminophen having greater efficacy than placebo in terms of primary endpoints [pain intensity differences from T0.5 to T3 (P < 0.05 in both studies)]. The use of IV acetaminophen also reduced the need for rescue opioid consumption, with patients receiving IV acetaminophen consuming, on average, less than half the amount of rescue medication as those receiving placebo. IV acetaminophen was effective in treating moderate-to-severe pain after total hip arthroplasty and reduced the need for rescue opioid consumption.

Intraperitoneal Bupivacaine-Meperidine Infiltration Versus Intravenous Paracetamol: A Comparison of Analgesic Efficacy in Post-Gynecologic Diagnostic Laparoscopic Pain

BACKGROUND

Pain following laparoscopy could be due to different causes requiring effective postoperative analgesia.

OBJECTIVES

In the present study, we evaluated the combined effect of intraperitoneal infiltration of bupivacaine-meperidine versus intravenous infusion of paracetamol on pain relief after diagnostic gynecologic laparoscopy.

PATIENTS AND METHODS

In this prospective study, 90 female subjects with ASA class I or II scheduled for gynecologic diagnostic laparoscopy were studied in two groups; group B + M received intraperitoneal infiltration of 40 mL bupivacaine 0.25% with 50 mg of meperidine, group P received normal saline via abdominal trocar and ten minutes before the end of operation, group P received infusion of paracetamol 1000 mg in normal saline. Postoperative pain was evaluated using VAS score in PACU and 1, 2, 4, 8, 12 and 24 hours after the operation. The time to the first analgesic administration and total analgesic requirements were recorded.

RESULTS

Group B + M had significantly lower pain score in the first 8 postoperative hours than group P (P < 0.05). Rescue meperidine (IM) requirement was significantly less in B + M group compared to group P. Time to first request for analgesia was different between the two groups (78 versus 60 min); however, the difference was not statistically significant.

CONCLUSIONS

Intraperitoneal Infiltration of bupivacaine with meperidine following surgery provided more appropriate analgesia after gynecologic diagnostic laparoscopy than administration of IV paracetamol.

Comparison of intra-peritoneal bupivacaine and intravenous paracetamol for postoperative pain relief after laparoscopic cholecystectomy

Background:

Nonsteroidal anti-inflammatory drugs used for postoperative analgesia have considerable adverse effects, with paracetamol having a different mechanism of action, superior side effect profile and availability in intravenous (IV) form, this study was conducted to compare intra-peritoneal bupivacaine with IV paracetamol for postoperative analgesia following laparoscopic cholecystectomy.

Aim:

The aim was to compare the efficacy of intra-peritoneal administration of bupivacaine 0.5% and IV acetaminophen for postoperative analgesia in patients undergoing laparoscopic cholecystectomy.

Settings and Design:

Randomized, prospective trial.

Materials and Methods:

A total of 60 patients of American Society of Anesthesiologists physical Status I and II scheduled for laparoscopic cholecystectomy were enrolled for this study. Group I received 2 mg/kg of 0.5% bupivacaine as local intra-peritoneal application and Group II patients received IV 1 g paracetamol 6^th hourly. Postoperatively, the patients were assessed for pain utilizing Visual Analog Scale (VAS), Visual Rating Prince Henry Scale (VRS), shoulder pain. The total number of patients requiring rescue analgesia and any side-effects were noted.

Statistical Analysis:

Data analysis was performed using Students unpaired t-test. SPSS version 11.5 was used.

Results:

The VAS was significantly higher in Group I compared with Group II at 8^th, 12^th and 24^th postoperative hour. At 1^st and 4^th postoperative hours, VAS was comparable between the two groups. Although the VRS was higher in Group I compared with Group II at 12^th and 24^th postoperative hour; the difference was statistically significant only at 24^th postoperative hour. None of the patients in either of the groups had shoulder pain up to 8 h postoperative. The total number of patients requiring analgesics was higher in Group II than Group I at 1^st postoperative hour.

Conclusion:

Although local anesthetic infiltration and intra-peritoneal administration of 0.5% bupivacaine decreases the severity of incisional, visceral and shoulder pain in the early postoperative period, IV paracetamol provides sustained pain relief for 24 postoperative hours after elective laparoscopic cholecystectomy.

Intravenous non-opioid analgesia for peri- and postoperative pain management: a scientific review of intravenous acetaminophen and ibuprofen

Pain is a predictable consequence following operations, but the management of postoperative pain is another challenge for anesthesiologists and inappropriately controlled pain may lead to unwanted outcomes in the postoperative period. Opioids are indeed still at the mainstream of postoperative pain control, but solely using only opioids for postoperative pain management may be connected with risks of complications and adverse effects. As a consequence, the concept of multimodal analgesia has been proposed and is recommended whenever possible. Acetaminophen is one of the most commonly used analgesic and antipyretic drug for its good tolerance and high safety profiles. The introduction of intravenous form of acetaminophen has led to a wider flexibility of its use during peri- and postoperative periods, allowing the early initiation of multimodal analgesia. Many studies have revealed the efficacy, safety and opioid sparing effects of intravenous acetaminophen. Intravenous ibuprofen has also shown to be well tolerated and demonstrated to have significant opioid sparing effects during the postoperative period. However, the number of randomized controlled trials confirming the efficacy and safety is small and should be used in caution in certain group of patients. Intravenous acetaminophen and ibuprofen are important options for multimodal postoperative analgesia, improving pain and patient satisfaction.

OFIRMEV: an old drug becomes new again

This was judged to be the first place winning submission for the American Dental Society of Anesthesiology Student Essay Award. Acetaminophen is an old drug that is now available in an intravenous formulation. Its advantages and disadvantages are reviewed, including its potential role in multimodal postoperative pain therapy.

Buccal acetaminophen provides fast analgesia: two randomized clinical trials in healthy volunteers

Background

Acetaminophen (APAP) by oral or intravenous (iv) routes is used for mild to moderate pain but may take time to be effective. When fast relief is required and/or oral or iv routes are not available because of the patient’s condition, the transmucosal route may be an alternative.

Methodology

A new transmucosal/buccal (b) pharmaceutical form of APAP dissolved in 50% wt alcohol is compared with other routes of administration. Two consecutive randomized, crossover, double-blind clinical trials (CT1: NCT00982215 and CT2: NCT01206985) included 16 healthy volunteers. CT1 compared the pharmacology of 250 mg bAPAP with 1 g iv APAP. CT2 compared the pharmacodynamics of 125 mg bAPAP with 1 g iv and 125 mg sublingual (s) APAP. Mechanical pain thresholds are recorded in response to mechanical stimuli applied on the forearm several times during 120 minutes. The objective is to compare the time of onset of antinociception and the antinociception (area under the curve) between the routes of administration with analysis of variance (significance P<0.05).

Results

bAPAP has a faster time of antinociception onset (15 minutes, P<0.01) and greater antinociception at 50 minutes (P<0.01, CT1) and 30 minutes (P<0.01, CT2) than ivAPAP and sAPAP. All routes are similar after 50 minutes.

Conclusion

bAPAP has a faster antinociceptive action in healthy volunteers. This attractive alternative to other routes would be useful in situations where oral or iv routes are not available. This finding must now be confirmed in patients suffering from acute pain of mild and moderate intensity.

Pain management in ambulatory surgery-a review

Day surgery, coming to and leaving the hospital on the same day as surgery as well as ambulatory surgery, leaving hospital within twenty-three hours is increasingly being adopted. There are several potential benefits associated with the avoidance of in-hospital care. Early discharge demands a rapid recovery and low incidence and intensity of surgery and anaesthesia related side-effects; such as pain, nausea and fatigue. Patients must be fit enough and symptom intensity so low that self-care is feasible in order to secure quality of care. Preventive multi-modal analgesia has become the gold standard. Administering paracetamol, NSIADs prior to start of surgery and decreasing the noxious influx by the use of local anaesthetics by peripheral block or infiltration in surgical field prior to incision and at wound closure in combination with intra-operative fast acting opioid analgesics, e.g., remifentanil, have become standard of care. Single preoperative 0.1 mg/kg dose dexamethasone has a combined action, anti-emetic and provides enhanced analgesia. Additional α-2-agonists and/or gabapentin or pregabalin may be used in addition to facilitate the pain management if patients are at risk for more pronounced pain. Paracetamol, NSAIDs and rescue oral opioid is the basic concept for self-care during the first 3–5 days after common day/ambulatory surgical procedures.

Intravenous paracetamol versus intramuscular pethidine in relief of labour pain in primigravid women

BACKGROUND

Intramuscular pethidine is one of most common opioids used for labour analgesia. There are a number of concerns in the literature regarding the use of pethidine. The aim of this study is to compare analgesic efficacy of paracetamol with pethidine for labour pain in normal vaginal delivery.

MATERIALS AND METHODS

In this single-blinded, randomised control trial, 80 primigravid singleton women with full-term pregnancy candidate for normal vaginal delivery, were entered the trial and divided in to pethidine (A) and paracetamol (B) groups. At the time of admission, age and body mass index of mother and gestational age based on last day of period were recorded. In both groups, intravenous promethazine and hyoscine were administered to each patient at the first stage of delivery. From beginning of active phase of delivery, patients in group A received 50 mg intramuscular pethidine injection. At the same time patients in group B, received an intravenous solution infusion containing 1000 mg paracetamol and 300 cc of normal saline. After child birth, average labour pain was assessed using Visual Analogue Scale (VAS) by direct questioning from patient in both groups.

RESULTS

After patients' selection, 19 individual omitted during study due to exclusion criteria and finally 30 patients in paracetamol group and 31 patients in pethidine group remained to enter the trial. There was no significant difference in age and BMI of mothers between both groups (P > 0.05). Maternal age and labour duration in paracetamol group had no meaningful difference with maternal age and labour duration of patients in pethidine group (P > 0.05). The average VAS pain score was significantly lower in paracetamol comparing to that of pethidine group (8.366 out of 10, 9.612 out of 10, respectively, P < 0.001).

CONCLUSION

It is concluded that intravenous paracetamol is more effective than intramuscular pethidine to relief labour pain in normal vaginal delivery.

Treatment of postoperative pain after total hip arthroplasty: comparison between metamizol and paracetamol as adjunctive to opioid analgesics-prospective, double-blind, randomised study

INTRODUCTION

Metamizole use has been limited because of its risk of agranulocytosis. However, more recent literature seems to support its safety. This prospective, randomised, double-blind study was conducted to compare the analgesic effects of intravenous metamizole or intravenous paracetamol in combination with morphine PCA during the first 24 h following total hip arthroplasty.

MATERIALS AND METHODS

One hundred ten consecutive patients were selected for study. The two study groups were (A) metamizole, (B) paracetamol. Postoperative pain therapy was provided by Morphine PCA pump. In the first treatment group (A group), all patients received intravenous metamizole 1.5 g every 8 h during the first 24 postoperative hours. In the second treatment group (B group), all patients received intravenous paracetamol 1 g every 8 h during the first 24 postoperative hours. Postoperative pain intensity was measured 1, 2, 3, 4, 6, 8, 10, 14, 18, 22 h after the end of surgery by a VAS.

RESULTS

Statistically significant differences in VAS pain values favoring metamizole were reported at 6-h (p = 0.038), 8-h (p = 0.036), 14-h (p = 0.011), 18-h (p < 0.001) and 22-h (p = 0.025) post-baseline. Mean cumulative pain values were 17.9 for metamizole and 30.6 for paracetamol.

CONCLUSIONS

In this study, we have also shown excellent efficacy of paracetamol and metamizole combined with opioids, but metamizole proved to be a better analgesic than paracetamol. It is also necessary to mention the financial aspect considering that intravenous paracetamol is about ten times more expensive than an equivalent analgesic doses of intravenous metamizole.

Sub-acute toxicity studies of acetaminophen in Sprague Dawley rats

The aim of the present study was to evaluate the sub-acute oral toxicity of acetaminophen in Sprague Dawley (SD) rats at 250 to 1000 mg/kg body weight (b.wt.). The following observations were noticed during the study. No mortality in male and female rats, at and up to the dose of 1000 mg/kg b.wt. There were abnormal clinical signs observed on female animals at 1000 mg/kg b.wt. dose level. There were no difference in body weight gain and no effect on the daily feed consumption. No toxicologically significant effect on the haematological parameters but liver and kidney related biochemical parameter showed significant difference at 1000 mg/kg b.wt. in females. No toxicologically significant effect on the urinalysis parameters, absolute and relative organ weights and gross pathological alterations; whereas histopathological alterations were observed in female liver at dose level of 1000 mg/kg b.wt. were observed. Based on the findings of this study, the No Observed Adverse Effect Level (NOAEL) of acetaminophen in SD rats, following oral administration at the doses of 250, 500 and 1000 mg/kg on daily basis was found to be 500 mg/kg b.wt.

A Study on Pre-Emptive Analgesic Effect of Intravenous Paracetamol in Functional Endoscopic Sinus Surgeries (FESSs): A Randomized, Double-Blinded Clinical Study

BACKGROUND

Functional Endoscopic Sinus Surgery (FESS) is associated with significant post-operative pain. Intravenous (iv) paracetamol provides pain relief in most patients who have undergone FESS. In some studies, it was found to be inadequate. It has been observed from previous studies conducted on patients undergoing other surgeries like abdominal surgeries that the analgesic efficacy of iv paracetamol improves when used Pre-emptively. There are no studies done previously on use of iv paracetamol Pre-emptively in FESS.

OBJECTIVE

The purpose of the study was to determine the post-operative analgesic effects of Pre-emptive intravenous (iv) paracetamol in FESS.

MATERIALS AND METHODS

Following institutional ethics committee approval, thirty nine American Society of Anesthesiology (ASA) physical status I-II patients were assigned in a randomized manner into two groups: Group I received iv paracetamol 1g, in 100mL, 15 minutes before induction and Group II received iv paracetamol 1g, in 100 mL, at the end of the surgery. The time to first analgesic use and the total analgesic consumed in 24 hours was recorded. Visual Analog Scale (VAS) pain scores were obtained from all patients at 0, 30 minutes, 1, 2, 6, 12 and 24 hours after the end of the Surgery.

RESULTS

Time to first analgesic requirement was significantly longer in Group I compared to Group II (p = 0.0329). Rescue analgesic consumption and post-operative VAS pain scores recorded were significantly lower in Group I compared to Group II (p < 0.05) until 24 after surgery.

CONCLUSION

Pre-emptive iv paracetamol in comparison to intra-operative paracetamol, provided effective and reliable post-operative analgesia after FESS.

Oral oxycodone plus intravenous acetaminophen versus intravenous morphine sulfate in acute bone fracture pain control: a double-blind placebo-controlled randomized clinical trial

OBJECTIVES

Bone fracture is a common cause of acute pain in emergency and orthopedics departments. Targeting the multifaceted mechanisms of pain with combinations of multiple analgesics (multimodal analgesia) can increase the pain control efforts efficacy and decrease the adverse effects of each medication.

METHODS

One hundred and fifty-three patients with acute bone fracture were randomly allocated to two groups receiving intravenous morphine sulfate (74 patients) or oral oxycodone plus intravenous acetaminophen (79 patients). Pain scores and drugs' adverse effects were assessed 10, 30 and 60 min after treatment.

RESULTS

Pain scores were similar between groups before, 30 and 60 min after medication but patients in morphine sulfate group experienced less pain 10 min after medication. Eight (10.8%) patients in morphine sulfate group and 26 (32.9%) patients in acetaminophen/oxycodone group experienced nausea that was statistically significant higher (P value = 0.001). Itching was seen in 12 (15.1%) patients of acetaminophen/oxycodone group and three (4.0%) patients of patients in morphine sulfate group (P value = 0.02).

CONCLUSION

Intravenous acetaminophen plus oral oxycodone is as effective as intravenous morphine sulfate in acute pain control in emergency department but with a less desirable safety profile.

Can intravenous paracetamol reduce opioid use in preoperative hip fracture patients?

Pain due to intra- and extracapsular hip fractures is usually treated with opioid medication. Paracetamol (acetaminophen in North America) has better bioavailability when given intravenously than orally and has been successfully used in the postoperative care of orthopedic patients. However, no study has evaluated its use in the preoperative trauma patient. Our unit conducted a prospective, consecutive cohort study to investigate the opioid-sparing effect of regularly administered intravenous paracetamol compared with oral paracetamol in preoperative hip fracture patients. The total opioid dose given, based on conversion to intravenous morphine, and the reported pain score were evaluated in 75 patients. There were 28 patients in the control group who were give routine oral paracetamol and oral opioids, with morphine for breakthrough pain. There were 47 patients in the study group who received only routine intravenous paracetamol, with opioids reserved for breakthrough pain. The patients in the 2 groups had similar characteristics. The mean preoperative oral paracetamol dose for the control group was 7.2 g compared with 6.3 g in the study group. There was a significant reduction (P<.005) in the mean total intravenous morphine with intravenous paracetamol (6.5 mg) compared with oral paracetamol (21.8 mg). There was no difference in the mean pain score between the groups, 2.1 vs 1.8 (P=.3). Intravenous paracetamol had a significant opioid-sparing effect and satisfactory pain relief in preoperative hip fracture patients.

Oral vs intravenous paracetamol for lower third molar extractions under general anaesthesia: is oral administration inferior?

BACKGROUND

Paracetamol formulations provide effective analgesia after surgery [Duggan ST, Scott LJ. Intravenous paracetamol (acetominophen). Drugs 2009; 69: 101-13; Toms L, McQuay HJ, Derry S, Moore RA. Single dose oral paracetamol (acetaminophen) for postoperative pain in adults. Cochrane Database Syst Rev 2008: CD004602]. I.V. paracetamol is superior to oral for pain rescue (Jarde O, Boccard E. Parenteral versus oral route increases paracetamol efficacy. Clin Drug Invest 1997; 14: 474-81). By randomized, double-blinded trial, we aimed to determine whether preoperative oral paracetamol provides inferior postoperative analgesia to preoperative i.v. paracetamol.

METHODS

One hundred and thirty participants received either oral paracetamol and i.v. placebo (Group OP), or oral placebo and i.v. paracetamol (Perfalgan™) (Group IP). Oral preparations were given at least 45 min before surgery; i.v. preparations after induction of anaesthesia. Pain was assessed by a 100 mm visual analogue scale (VAS) 1 h from the end of surgery. Rescue analgesia was given on request.

RESULTS

A total of 128 patients completed the study. There were no significant differences in baseline characteristics or intraoperative variables between the groups. The study was designed to reveal whether OP is inferior to IP, with an inferiority margin of 20%. The number of patients reporting satisfactory analgesia at 1 h with VAS ≤ 30 mm were 15 (OP) and 17 (IP), respectively. The secondary outcome measure of the mean (standard deviation) VAS (mm) for the whole of each group was 52 (22) for OP and 47 (22) for IP. Analysis of confidence intervals indicates that oral paracetamol is not inferior to i.v. paracetamol. The median survival (90% CI) to rescue analgesia request was 54.3 (51.2-57.4) min in Group OP and 57.3 (55.4-59.2) min in Group IP; there was no significant difference in this measure.

CONCLUSIONS

In this study of lower third molar extraction, oral paracetamol is not inferior to i.v. for postoperative analgesia. ISRCTN Registration http://www.controlled-trials.com/ISRCTN77607163.

Role of intravenous acetaminophen in postoperative pain management

SUMMARY The need to safely treat the postoperative pain of patients is apparent. Opioids, although effective, have multiple morbidities associated with their use. A multimodal approach to postoperative pain management can serve to minimize the undesirable effects of opioids. Intravenous acetaminophen (paracetamol) has recently become available in the USA where many practitioners are not familiar with this drug. This article reviews the history, pharmacology and clinical uses of intravenous acetaminophen in the treatment of perioperative pain.

Postoperative plasma paracetamol levels following oral or intravenous paracetamol administration: a double-blind randomised controlled trial

In day-case surgery paracetamol is commonly given orally preoperatively, or intravenously intraoperatively. In this double-blind randomised controlled trial we investigated which of these methods of administration achieved therapeutic plasma levels most effectively in the early postoperative period. Thirty patients undergoing day case arthroscopy of the knee were randomised to receive either 1.0 g oral paracetamol 30 to 60 minutes preoperatively (20 patients) or 1.0 g intravenous paracetamol intraoperatively (10 patients). Plasma paracetamol levels were measured 30 minutes after arrival in the recovery room. Secondary outcomes included postoperative pain scores, rescue analgesia requirements and duration of stay in the recovery room. All patients receiving the intravenous preparation had plasma levels above the analgesic level compared to less than half (7/20) in the oral group. Mean plasma paracetamol levels were 88.6 µmol/l for the intravenous group and 53.2 µmol/l for the oral group (P=0.0005). There were trends towards reduced rescue analgesia and duration of stay in the recovery room for the intravenous group although not reaching statistical significance. There was no difference in pain scores between groups. Intraoperative administration of 1.0 g of intravenous paracetamol more reliably achieved effective paracetamol levels in the early postoperative period compared to an equal dose given orally preoperatively. Only a minority of patients receiving the 1.0 g oral dose preoperatively had plasma levels in the therapeutic analgesic range.

Postoperative analgesia for gynecological laparoscopy

Gynecological laparoscopy is a commonly performed procedure. Providing anesthesia for this can present a challenge, particularly in the day surgery population. Poor analgesia, nausea, and vomiting can cause distress to the patient and increased cost for the health system, because of overnight admission. In this review we discuss anesthetic and analgesic techniques for day-case gynecological laparoscopy. The principles include multimodal analgesia, the use of the oral route wherever possible, and the contribution of the surgeon.