A randomized study of the efficacy and safety of intravenous acetaminophen compared to oral acetaminophen for the treatment of fever

Risk Factors for Intravenous Acetaminophen-Induced Hypotension in Patients with Repeated Acetaminophen Administration

PURPOSE

Intravenous (IV) acetaminophen-induced hypotension is a clinically significant issue that remains difficult to predict. Therefore, this study aimed to identify the factors associated with hypotension in patients with repeated IV acetaminophen administration.

MATERIALS AND METHODS

This observational cohort study included patients who received IV acetaminophen in the critical care unit of the Yongin Severance Hospital in 2020. All IV acetaminophen administration records for each patient were reviewed, and the blood pressure records within 2 h after IV acetaminophen administration were examined. Changes in blood pressure within 2 h of IV acetaminophen administration were monitored to identify hypotension, defined as a systolic blood pressure <90 mm Hg, a decrease in systolic blood pressure by 30 mm Hg, or a decrease in mean arterial pressure by 15%.

RESULTS

There were 1547 instances of IV acetaminophen administration among 398 patients. Of these, 416 instances (26.9%) resulted in hypotension among 204 patients (51.3%). A history of IV acetaminophen-induced hypotension did not predict subsequent hypotensive episodes, and there was no consistent tendency. The use of beta-blocker [odds ratio (OR)=1.50], gastrointestinal (GI) infection (OR=1.42), and septic shock (OR=1.68) were significant risk factors for IV acetaminophen-induced hypotension in multivariate analysis. In subgroup analysis of cases with beta-blocker, heart failure (OR=1.91), urinary tract infection (OR=2.16), GI infection (OR=1.83) were significant risk factors.

CONCLUSION

Severe infections, heart failure, and the use of beta-blockers are associated with IV acetaminophen-induced hypotension. However, IV acetaminophen-induced hypotension is inconsistent and depends on the patient's condition.

The Effect of Paracetamol and Codeine Analgesic Combination on Serum Alanine Aminotransferase and Aspartate Aminotransferase Levels in Male Wistar Rats

BACKGROUND: Paracetamol and codeine are classified as different analgesic categories with different mechanism. The combination of both paracetamol and codeine as an analgesic works synergistically and may give better outcome in pain management in moderate-to-severe degree. However, the combination of those analgesics might bring side effects in liver. AIM: This study was to determine the effect of analgesic combination of paracetamol and codeine on alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels of Wistar rats. METHODS: This study was an experimental study with a pre- and post-test control group design. The study objects were 20 male Wistar rats with certain criteria, which were randomly divided into four groups, that is, control group (C), group with paracetamol therapy alone (32 mg/kgBW), group with codeine therapy alone (1.9 mg/kgBW), and group with combination therapy of paracetamol (32 mg/kgBW) and codeine (1.9 mg/kgBW). Analgesic drugs were administered orally 4 times a day for 28 days with gastric sonde. On the 29th day, blood samples were collected through retro-orbital blood vessels for measuring ALT and AST levels. Statistical tests used were one-way ANOVA and Kruskal–Wallis test. RESULTS: They showed that there were no differences in ALT levels between C, P1, P2, and P3 in both at baseline and post-treatment. However, there were significant increases in ALT levels after treatment in comparison to baseline in the control group (C) (87.2 ± 18.43 vs. 40.6 ± 5.02; p < 0.05), P1 (78.9 ± 8.52 vs. 44.4 ± 1.14; p < 0.05), and P3 (86.4 ± 17.22 vs. 44.0 ± 1.00; p < 0.05). There were no differences in AST levels between C, P1, P2, and P3 at baseline, but there were significantly higher AST levels in P1, P2, and P3 in comparison to control at post-treatment (p < 0.05). There were no differences in AST levels between P1, P2, and P3 at post-treatment (p > 0.05). There were also significant increases in AST levels after treatment in comparison to baseline in the control group (C) (93.9 ± 1.10 vs. 37.7 ± 1.69; p < 0.05), P1 (97.6 ± 1.85 vs. 36.3 ± 1.22; p < 0.05), P2 (97.6 ± 1.70 vs. 37.7 ± 1.73; p < 0.05), and P3 (98.6 ± 0.79 vs. 36.4 ± 1.20; p < 0.05). CONCLUSION: The combination therapy of paracetamol and codeine might not bring difference in serum ALT and AST levels compared to paracetamol therapy alone or codeine therapy alone.

From basic to advanced computerised intravenous to oral switch for paracetamol and antibiotics: an interrupted time series analysis

OBJECTIVES

Early switch from intravenous to oral therapy of bioequivalent drugs has major advantages but remains challenging. At our hospital, a basic clinical rule was designed to automatically alert the physician to review potential intravenous to oral switch (IVOS). A rather low acceptance rate was observed. In this study, we aimed to develop, validate and investigate the effect of more advanced clinical rules for IVOS, as part of a centralised pharmacist-led medication review service.

DESIGN AND SETTING

A quasi-experimental study was performed in a large teaching hospital in Belgium using an interrupted time series design.

INTERVENTION

A definite set of 13 criteria for IVOS, focusing on the ability of oral absorption and type of infection, was obtained by literature search and validated by a multidisciplinary expert panel. Based on these criteria, we developed a clinical rule for paracetamol and one for ten bioequivalent antibiotics to identify patients with potentially inappropriate intravenous prescriptions (PIVs). Postintervention, the clinical rule alerts were reviewed by pharmacists, who provided recommendations to switch in case of eligibility.

PRIMARY AND SECONDARY OUTCOME MEASURES

A regression model was used to assess the impact of the intervention on the number of persistent PIVs between the preintervention and the postintervention period. The total number of recommendations, acceptance rate and financial impact were recorded for the 8-month postintervention period.

RESULTS

At baseline, a median number of 11 (range: 7-16) persistent PIVs per day was observed. After the intervention, the number reduced to 3 (range: 1-7) per day. The advanced IVOS clinical rules showed an immediate relative reduction of 79% (incidence rate ratio=0.21, 95% CI 0.13 to 0.32; p<0.01) in the proportion of persistent PIVs. No significant underlying time trends were observed during the study. Postintervention, 1091 recommendations were provided, of which 74.1% were accepted, resulting in a total 1-day cost saving of €4648.35.

CONCLUSIONS

We showed the efficacy of advanced clinical rules combined with a pharmacist-led medication review for IVOS of bioequivalent drugs.

Intravenous Versus Oral Acetaminophen Use in Febrile Neurocritical Care Patients

The use of intravenous (IV) acetaminophen (APAP) for fever has not been thoroughly studied in neurocritical care (NCC) patients, in whom a temperature of ≥38°C is associated with poor outcomes and treatment to normothermia is common practice. This retrospective study evaluated NCC patients admitted between May 1, 2012, and April 30, 2013, and received at least one dose of IV or oral (PO) APAP for a body temperature of ≥38°C. The primary aim of this study was to compare the reduction in body temperature (RIT) between IV and PO APAP, calculated as the change in temperature before and 0.5, 1, 2, 3, and 6 hours after administration. Descriptive statistics were used to assess use characteristics, and Kruskal-Wallis and Mann-Whitney U tests were used for between-group differences. There were 142 NCC patients who received a total of 405 IV APAP and 253 PO APAP doses. Seventy percent of all APAP doses resulted in a temperature of <38°C within 6 hours. The median oral body temperature before APAP was 38.8°C and 38.6°C for IV and PO APAP, respectively (p < 0.01). The median RIT at 0.5 (IV 0.25°C vs. PO 0.2°C), 1 (IV 0.4°C vs. PO 0.2°C), 2 (IV 0.7°C vs. PO 0.5°C), 3 (IV 0.9°C vs. PO 0.6°C), and 6 (IV 1°C vs. PO 0.8°C) hours was significantly greater for IV APAP than for PO APAP at all time points (p < 0.05). Patients with an acute ischemic stroke and patients with an intracerebral hemorrhage had a statistically significantly greater RIT with IV APAP therapy. IV APAP administered to febrile NCC patients was associated with a significantly greater RIT than PO, but 70% of all APAP doses resulted in a body temperature of <38°C within 6 hours. Further prospective studies are needed to determine if IV APAP improves clinical outcomes.

Comparison of intravenous ibuprofen and paracetamol in the treatment of fever: A randomized double-blind study

OBJECTIVE

Fever is one of the frequent reasons for admission to the emergency department. Studies comparing oral forms of non-steroidal anti-inflammatory drugs (NSAIDs) and paracetamol with intravenous (IV) forms for fever are common in the literature. Our study is the first emergency department study comparing IV forms of ibuprofen and paracetamol in the treatment of febrile patients.

METHODS

A randomized, double-blind study was conducted in a tertiary university emergency department for a six-month period. Patients aged 18-65 years who had a fever of ≥38.0 °C were included. Patients were administered 400 mg of IV ibuprofen and 1000 mg of IV paracetamol. The primary aim of the study was to determine whether there was a difference in the effect of the two drugs on fever. The secondary aim was to investigate whether there was a difference in terms of numeric rating scale (NRS) measurements and the need for additional antipyretic therapy.

RESULTS

A total of 200 people, 100 of whom were female, were included in the study. The mean age was 30.77 ± 10.61 years. The mean initial temperature for ibuprofen and paracetamol was 38.79 ± 0.470 °C and 38.70 ± 0.520 °C, respectively, with no difference noted between the groups (p = 0.380). It was found that both drugs significantly provided fever control in the first 30 min (p < 0.001), with no difference between them in terms of fever reduction (p = 0.980). Both drugs significantly improved in accompanying symptoms, although both drugs did not show superiority to each other (p = 0.0226). When evaluated in terms of a need for rescue medication, no significant difference was found between the two drugs (p = 0.404). No side effects were encountered during the study.

CONCLUSION

In adult age group patients admitted to the emergency department with high fever, the IV forms of 1000 mg paracetamol and 400 mg ibuprofen effectively and equally reduce complaints, such as fever and accompanying pain. They can be effectively used as each other's rescue medicine and as an alternative to each other in patients with comorbid diseases.

Randomized control trial of intravenous acetaminophen for reduction of intrapartum maternal fever

BACKGROUND

Intravenous acetaminophen reaches a higher mean peak plasma concentration than oral acetaminophen in a shorter period of time. The favorable pharmacokinetics of intravenous acetaminophen may be beneficial for treating intrapartum maternal fever.

OBJECTIVE

The primary objective was to compare intravenous and oral acetaminophen in time to defervescence (temperature <38°C). The secondary objective was to compare intravenous and oral acetaminophen in the percentage of participants being afebrile and percent reduction in maternal temperature 30 minutes after administration of first dose. Other outcomes evaluated were histopathological placental findings; neonatal outcomes; oxidative stress; and levels of RANTES, interferon-δ, interleukin 1β, interleukin 2, interleukin 4, interleukin 6, interleukin 8, interleukin 10, interleukin 13, and tumor necrosis factor-α in maternal and neonatal blood.

STUDY DESIGN

This was a randomized, comparator-controlled, double-dummy, double-blind clinical trial. At the onset of intrapartum fever ≥38°C, patients ≥36 weeks' gestation were either randomized to the control or experimental study arm. Patients in the control arm received 1000 mg of oral acetaminophen capsules and an intravenous placebo resembling intravenous acetaminophen. Patients randomized to the experimental arm received 1000 mg of intravenous acetaminophen and oral placebo capsules resembling acetaminophen. Maternal temperatures and fetal heart rates were recorded at consecutive intervals following administration of the first dose of acetaminophen. Maternal blood, collected at the onset of fever and after delivery, and neonatal cord blood collected at delivery were evaluated for oxidative stress (glutathione levels), levels of RANTES and cytokines (interferon-δ, interleukin 1β, interleukin 2, interleukin 4, interleukin 6, interleukin 8, interleukin 10, interleukin 13, and tumor necrosis factor-α). Placentas were collected for pathologic review. A P value of <.05 was considered statically significant.

RESULTS

A total of 121 patients (55 in the intravenous and 66 in the oral group) were recruited from December 1, 2016, to February 28, 2018. Patient demographics and intrapartum factors were similar between both arms. The intravenous group showed a mean time of 54.86 minutes (95% confidence interval, 20.57-39.43) to defervescence vs 52.58 minutes (95% confidence interval, 16.58-43.42) in the oral group (P=.71). In addition, intravenous and oral acetaminophen showed similar results in percentage of patients being afebrile and percent reduction in maternal temperature 30 minutes after administration of the first dose. Histopathological findings, neonatal outcomes, oxidative stress markers, and RANTES and cytokine levels were not statistically significant between intravenous and oral acetaminophen groups.

CONCLUSION

Intravenous acetaminophen did not demonstrate a higher efficacy than oral acetaminophen in treating intrapartum maternal fever. Select patients may benefit from intravenous acetaminophen for treatment of intrapartum fever, including those who cannot tolerate oral medication.

How to manage fever in brain-injured patients

Fever represents a frequent and dangerous secondary insult for the injured brain and is often associated with worsened neurological outcomes. The identification of fever in the Neuro-Intensive Care Unit requires careful monitoring and rapid and effective treatment. The main objective of this article was to provide practical information regarding temperature monitoring, triggers for intervention and fever management in brain injured patients.

Hospitalization costs and resource allocation in cholecystectomy with use of intravenous versus oral acetaminophen

OBJECTIVE

To evaluate intravenous (IV) acetaminophen (APAP) vs oral APAP use as adjunctive analgesics in cholecystectomy patients by comparing associated hospital length of stay (LOS), hospital costs, opioid use, and rates of nausea/vomiting, respiratory depression, and bowel obstruction.

METHODS

We conducted a retrospective analysis of the Premier Database (January 2012 to September 2015) including cholecystectomy patients who received either IV APAP or oral APAP. Differences in LOS, hospitalization costs, mean daily morphine equivalent dose (MED), and potential opioid-related adverse events were estimated. Multivariable logistic regression was performed for the binary outcomes and instrumental variable regressions, using the quarterly rate of IV APAP use for all hospitalizations by hospital as the instrument in two-stage least squares regressions for continuous outcomes. Models were adjusted for patient demographics, clinical risk factors, and hospital characteristics.

RESULTS

Among 61,017 cholecystectomy patients, 31,133 (51%) received IV APAP. Subjects averaged 51 and 57 years of age, respectively, in the IV and oral APAP cohorts. In the adjusted models, IV APAP was associated with 0.42 days shorter LOS (95% CI = -0.58 to -0.27; p < .0001), $1,045 lower hospitalization costs (95% CI = -$1,521 to -$569; p < .0001), 2 mg lower average daily MED (95% CI = -3 mg to -0.9 mg; p = .0005), and lower rates of respiratory depression (odds ratio [OR] = 0.89, 95% CI = 0.82-0.97; p = .006), and nausea and vomiting (OR = 0.86, 95% CI = 0.86-0.86; p < .0001).

CONCLUSIONS

In patients having cholecystectomy, the addition of IV APAP to perioperative pain management is associated with shorter LOS, lower costs, reduced opioid use, and less frequent nausea/vomiting and respiratory depression compared to oral APAP. These findings should be confirmed in a prospective study comparing IV and oral APAP.

Comparison of Antipyretic Efficacy of Intravenous (IV) Acetaminophen versus Oral (PO) Acetaminophen in the Management of Fever in Children

OBJECTIVE

To assess the dynamics of the onset of antipyretic efficacy of intravenous (IV) acetaminophen vs. oral (PO) acetaminophen in the management of fever in children.

METHODS

This observational single-dose study was conducted at Department of Pedriatrics, Army Hospital (Research and Referral), a multispecialty tertiary care center in New Delhi in fever patients to assess the antipyretic efficacy of IV acetaminophen 15 mg/kg/dose vs. PO acetaminophen 15 mg/kg/dose over 6 h. Subjects were randomly assigned to receive either IV acetaminophen (n = 200) or PO acetaminophen (n = 200).

RESULTS

Demographics and baseline characteristics were similar between the two groups and were normally distributed. Allergic reaction was found in 7 (3.5%) patients in IV acetaminophen group and was absent in PO acetaminophen group. Onset of constipation and dry mouth was found in 8 patients (4%) in IV acetaminophen group and was absent in PO acetaminophen group. Additional dose was required in 6 patients (3%) in intravenous acetaminophen group and 10 patients (5%) in oral acetaminophen group respectively. Statistically significant differences in the rate of fall in temperature through 180 min were observed in favor of the IV acetaminophen group when compared to those receiving PO acetaminophen.

CONCLUSIONS

A single dose of intravenous acetaminophen is safe and effective in reducing fever where patients are unable to tolerate oral administration or when rapid reduction of temperature is desirable.

Randomized, controlled, multicentre clinical trial of the antipyretic effect of intravenous paracetamol in patients admitted to hospital with infection

Aim

No randomized study has been conducted to investigate the use of intravenous paracetamol (acetaminophen, APAP) for the management of fever due to infection. The present study evaluated a new ready‐made infusion of paracetamol.

Methods

Eighty patients with a body temperature onset ≥38.5°C in the previous 24 h due to infection were randomized to a single administration of placebo (n = 39) or 1 g paracetamol (n = 41), and their temperature was recorded at standard intervals. Rescue medication with 1 g paracetamol was allowed. Serum samples were collected for the measurement of APAP and its metabolites. The primary endpoint was defervescence, defined as a core temperature ≤37.1°C.

Results

During the first 6 h, defervescence was achieved in 15 (38.5%) patients treated with placebo compared with 33 (80.5%) patients treated with paracetamol 1 g (P < 0.0001). The median time to defervescence with paracetamol 1 g was 3 h. Rescue medication was given to 15 (38.5%) and five (12.2%) patients allocated to placebo and paracetamol, respectively (P = 0.007); nine (60.0%) and two (40.0%) of these patients, respectively, experienced defervescence. No further antipyretic medication was needed for patients becoming afebrile with rescue medication. Serum glucuronide‐APAP concentrations were significantly greater in the serum of patients who did not experience defervescence with paracetamol. The efficacy of paracetamol was not affected by serum creatinine. No drug‐related adverse events were reported.

Conclusions

The 1 g paracetamol formulation has a rapid and sustainable antipyretic effect on fever due to infection. Its efficacy is dependent on hepatic metabolism.

IV Acetaminophen Results in Lower Hospital Costs and Emergency Room Visits Following Bariatric Surgery: a Double-Blind, Prospective, Randomized Trial in a Single Accredited Bariatric Center

BACKGROUND

Postoperative pain control in bariatric surgery is challenging, despite use of intravenous (IV) narcotics. IV acetaminophen is one pain control alternative.

OBJECTIVE

The aim of this study was to investigate the economic impact of IV acetaminophen in bariatric surgery and its effect on patients' pain, satisfaction, and hospital length of stay.

METHODS

In a randomized controlled trial, Group 1 (treatment) received IV acetaminophen plus IV narcotics 30 min before surgery, then medication plus IV narcotics/PO narcotics for the remaining 18 h. Group 2 (control) received IV normal saline plus IV/PO narcotics. Patients underwent laparoscopic Roux-en-Y gastric bypass (LRYGB) or laparoscopic sleeve gastrectomy (SG). Primary outcomes included direct hospital costs, length of stay, postoperative pain, and patient satisfaction. Secondary outcomes included indirect costs, rescue narcotics dosage, and 30-day outcomes.

RESULTS

Mean direct hospital cost in the treatment group (n = 50) was $3089.18 versus $2991.62 for the control group (n = 50) (p > 0.05). Pain scores did not differ significantly (p = 0.61). After adjusting for surgery type, there was no significant difference in length of stay (p = 0.95). Significantly more control group patients incurred surgery-related indirect costs (10 versus 2%, p < 0.05), with greater presentation to the emergency department (ED) for abdominal pain (5/50 versus 1/50), yielding higher total indirect costs ($39,293 versus $13,185).

CONCLUSIONS

Using IV acetaminophen for postoperative pain management produced notable indirect cost savings and reduced ED visits in the first 30 days postoperatively, with good safety and tolerance. Decreased statistical power may have accounted for certain non-significant findings.

Postmarketing review of intravenous acetaminophen dosing based on Food and Drug Administration prescribing guidelines

STUDY OBJECTIVES

To evaluate the appropriateness of intravenous acetaminophen dosing-prescribed dose, frequency, duration, and indication-based on United States Food and Drug Administration (FDA)-approved prescribing guidelines and to evaluate the adverse effect profile of intravenous acetaminophen.

DESIGN

Retrospective chart review.

SETTING

United States Navy medical center.

PATIENTS

Three hundred patients who received intravenous acetaminophen from August 1, 2011, to August 1, 2012.

MEASUREMENTS AND MAIN RESULTS

The indications, dose, frequency, and duration of intravenous acetaminophen were recorded for each patient. Adverse effects of intravenous acetaminophen were analyzed by thoroughly reviewing any adverse effects documented, including nausea, vomiting, headache, or any symptom specifically attributed to the drug. Baseline liver function tests, including aspartate aminotransferase and alanine aminotransferase levels, and elevations 3 times the upper limit of normal during intravenous acetaminophen therapy were recorded. The average patient weight was 78±21 kg, with 12 patients (4%) weighing less than 50 kg and 288 (96%) patients weighing 50 kg or greater. Two hundred forty-one patients (80%) were appropriately dosed, whereas 59 (20%) patients were not appropriately dosed based on the FDA-approved dosing. No patients exceeded the FDA-approved maximum daily dosing recommendations for intravenous acetaminophen (4 g). Sixty-five patients (22%) received intravenous acetaminophen for longer than 24 hours. Intravenous acetaminophen was well tolerated, without any reported adverse effects, including the commonly reported adverse effects of nausea, vomiting, headache, and insomnia. Ten patients (3%) had a documented history of liver disease and did not experience any adverse effects or increases in liver function tests after the administration of intravenous acetaminophen.

CONCLUSION

Intravenous acetaminophen appeared to be a safe and effective analgesic and antipyretic agent. Dosing for patients weighing less than 50 kg needs to be appropriately weight adjusted. Intravenous acetaminophen can be used alone or in conjunction with opioids and other analgesics. Limitations of this study include its retrospective design, inability to assess outcomes of reducing opioid use, and short-term observation period.

Intravenous acetaminophen use in pediatrics

Acetaminophen is a commonly used pediatric medication that has recently been approved for intravenous use in the United States. The purpose of this article was to review the pharmacodynamics, indications, contraindications, and precautions for the use of intravenous acetaminophen in pediatrics.

Intravenous paracetamol for fever control in acute brain injury patients: cerebral and hemodynamic effects

BACKGROUND

Fever occurs frequently in acute brain injury patients, and its occurrence is associated with poorer outcomes. Paracetamol, an antipyretic frequently employed in patients with cerebral damage, may cause hypotension. We evaluated the cerebral and hemodynamic effects of intravenous (IV) paracetamol for the control of fever in Neuro-Intensive Care Unit (NICU) patients.

METHODS

This is a prospective observational study in which we enrolled 32 NICU patients: Subarachnoid Hemorrhage (SAH, n = 18), Traumatic Brain Injury (TBI, n = 10), Intracerebral Hemorrhage (ICH, n = 2) and Acute Ischemic Stroke (AIS, n = 2).

RESULTS

The administration of paracetamol resulted in a decrease of core body temperature (Tc) (p = 0,0001), mean arterial pressure (MAP) (p = 0,0006), cerebral perfusion pressure (CPP) (p = 0,0033), and jugular venous oxygen saturation (SjVO2) (p = 0.0193), and in an increase of arteriojugular venous differences of oxygen (AVDO2) (p = 0.0012). The proportion of patients who had an infusion of norepinephrine increased from 47 % to 75 % (p = 0.0039 McNemar Test). When intracranial pressure (ICP) at the start of paracetamol infusion (t-0) was compared with the measurement of ICP after 2 h, a significant correlation was observed (r = 0.669, p = 0.0002). This marked and significant correlation can be explained by the fact that for the higher levels of ICP assessed at t-0 (greater than 15 mmHg), we observed a marked reduction of ICP concomitant with the decrease of Tc. No problems related to norepinephrine administration and/or increase in dosage were observed.

CONCLUSION

Paracetamol administration is effective but exposes patients to hypotensive episodes that must be recognized and treated expeditiously to prevent further damage to the injured brain.

Best practice for fever management with intravenous acetaminophen in pediatric oncology

Intravenous (IV) acetaminophen was introduced in the United States in 2011 for use as an analgesic and antipyretic agent. While no studies have looked at its utilization specifically in the pediatric oncology population, existing literature suggests IV acetaminophen is safe and effective to use in both children and adults. This article aims to review and apply current data in evaluating whether or not children with cancer can safely benefit from its use. This article provides clinical indications, safety and efficacy profiles, and nursing implications along with recommendations for future study regarding the use of IV acetaminophen in this population.

Drug utilization, dosing, and costs after implementation of intravenous acetaminophen guidelines for pediatric patients

OBJECTIVES

The objectives of this evaluation of medication use were to characterize the use of intravenous acetaminophen at our institution and to determine if acetaminophen was prescribed at age-appropriate dosages per institutional guidelines, as well as to evaluate compliance with restrictions for use. Total acquisition costs associated with intravenous acetaminophen usage is described as well.

METHODS

This retrospective study evaluated the use of acetaminophen in pediatric patients younger than 18 years of age, admitted to a tertiary care hospital, who received at least 1 dose of intravenous acet-aminophen between August 1, 2011, and January 31, 2012.

RESULTS

A total of 52 doses of intravenous acetaminophen were administered to 31 patients during the 6-month study period. Most patients were admitted to the otorhinolaryngology service (55%), and the majority of doses were administered either in the operating room (46%) or in the intensive care unit (46%). Nineteen doses (37%) of intravenous acetaminophen were administered to patients who did not meet institutional guidelines' eligibility criteria. Three patients received single doses of intravenous acetaminophen that were greater than the dose recommended for their age. One patient during the study period received more than the recommended 24-hour maximum cumulative dose for acetaminophen. Total acquisition cost of intravenous acetaminophen therapy over the 6-month study period was $530.40.

CONCLUSIONS

Intravenous acetaminophen was used most frequently among pediatric patients admitted to the otorhinolaryngology service during the perioperative period. Nineteen doses (37%) were administered to patients who did not meet the institutional guidelines' eligibility criteria. Our data support reinforcing the availability of institutional guidelines to promote cost-effective use of intravenous acetaminophen while minimizing the prescription of inappropriate doses.

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.

Physical and chemical compatibility of injectable acetaminophen during simulated y-site administration

PURPOSE

The physical and chemical compatibility of intravenous acetaminophen with commonly administered injectable medications was evaluated.

METHODS

Simulated Y-site evaluation was accomplished by mixing 2 mL of acetaminophen (10 mg/mL) with 2 mL of an alternative intravenous medication and subsequently storing the mixture in a polypropylene syringe for 4 hours. The aliquot solutions were visually inspected and evaluated for crystal content at 4 hours by infusing 4 mL of the medication mixture through a 0.45-μm nitrocellulose filter disc. Medication mixtures that were selected for chemical stability testing were analyzed by high-performance liquid chromatography at 0, 1, and 4 hours using a Zorbax Eclipse Plus C18, 4.6 x 100 mm, 3.5-μm column for separation of analytes with subsequent diode-array detection. Medications were considered chemically compatible if the concentrations of all components were >90% of the original concentrations during the 4 hour simulated Y-site compatibility test.

RESULTS

U.S. Pharmacopeial Convention (USP) standards for physical particle counts were met for acetaminophen injection (10 mg/mL) when combined with cefoxitin, ceftriaxone, clindamycin, dexamethasone, diphenhydramine, dolasetron, fentanyl, granisetron, hydrocortisone, hydromorphone, ketorolac, meperidine, methylprednisolone, midazolam, morphine, nalbuphine, ondansetron, piperacillin/tazobactam, ranitidine, and vancomycin. Injectable acetaminophen is incompatible with acyclovir and diazepam and therefore should not be administered concomitantly with either of these products. Further testing confirmed the chemical compatibility of acetaminophen with ceftriaxone, diphenhydramine, granisetron, ketorolac, nalbuphine, ondansetron, piperacillin/tazobactam, and vancomycin.

CONCLUSION

All medications tested with acetaminophen were physically compatible except for acyclovir and diazepam. All 8 medications tested for chemical compatibility with acetaminophen were stable over the 4 hour simulated Y-site administration study.

Randomized controlled study of the antipyretic efficacy of oral paracetamol, intravenous paracetamol, and intramuscular diclofenac in patients presenting with fever to the emergency department

Background

Fever is a common problem in adults visiting the emergency department. Extensive studies have been done in children comparing the efficacy of various antipyretics. However, studies on the efficacy of antipyretic drugs in adults are very scarce. To the best of our knowledge, no controlled trial has been carried out comparing the antipyretic efficacy of paracetamol (oral and intravenous) and intramuscular diclofenac in adults.

Methods

In this parallel-group, open-label trial, participants aged 14–75 years presenting with fever who had a temperature of more than 38.5°C were enrolled and treated. Participants were randomly allocated to receive treatment with 1,000 mg oral paracetamol (n = 145), 1,000 mg intravenous paracetamol (n = 139), or 75 mg intramuscular diclofenac (n = 150). The primary outcome was degree of reduction in mean oral temperature at 90 minutes. The efficacy of diclofenac versus oral and intravenous paracetamol was assessed by superiority comparison. Analysis was done using intention to treat principles.

Results

After 90 minutes, all three groups showed a significant reduction in mean temperature, with intramuscular diclofenac showing the greatest reduction (−1.44 ± 0.43, 95% confidence interval [CI] −1.4 to −2.5) and oral paracetamol the least (−1.08 ± 0.51, 95% CI −0.99 to −2.2). After 120 minutes, there was a significant difference observed in the mean change from baseline temperature between the three treatment groups (P < 0.0001). Significant changes in temperature were observed in favor of intramuscular diclofenac over oral and intravenous paracetamol at each time point from 60 minutes through 120 minutes inclusive.

Conclusion

Both intramuscular diclofenac and intravenous paracetamol showed superior antipyretic activity than oral paracetamol. However, in view of its ease of administration, intramuscular diclofenac can be used as a first-choice antipyretic in febrile adults in the emergency department.

Transformation of acetaminophen using manganese dioxide-mediated oxidative processes: reaction rates and pathways

This study investigates the oxidative transformation kinetics of acetaminophen (APAP) by δ-MnO2 under different conditions. APAP was rapidly oxidized by δ-MnO2 with the generation of Mn(2+). The measured APAP reaction rate considerably increased with an increase in initial δ-MnO2 and APAP concentration, but decreased as pH increased. The APAP reaction rate also increased with an increase in temperature. The addition of inorganic ions (Mn(2+), Ca(2+), and Fe(3+)) and substituted phenols (guaiacol, caffeic acid, and p-coumaric acid) as co-solutes remarkably decreased the transformation rate of APAP. The UV-Vis absorption spectra exhibited the π → π* transition, typical for aromatic rings. In addition, the intensity of the absorption peak gradually improved with increasing reaction time, suggesting that APAP can polymerize to form oligomers. Moreover, the secondary mass spectra of the dimers elucidated that the dimers were formed by the covalent bonding of phenol aromatic rings. Moreover, the higher-degree oligomers were formed by the coupling polymerization of phenolic and anilidic groups of dimers. These results are useful in understanding the fate of APAP in natural systems.

In vitro clearance of intravenous acetaminophen in extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is a life support system used as a bridge to transplantation in critically ill patients who suffer from acute respiratory or cardiac failure with resultant hypoxemia and tissue hypoxia. This is not amendable to conventional support intervention. Previous studies have shown significant drug losses in the components of an ECMO circuit, leading to decreased plasma drug levels. An in vitro study was conducted to determine: (1) changes in intravenous acetaminophen levels over time and (2) changes in concentration observed between different sites of the ECMO circuit. A single bolus dose of intravenous (IV) acetaminophen was injected into a standard blood-primed ECMO circuit. Plasma drug concentrations in the circuit were then measured at specific time points at three different locations to determine concentrations of the drug at time 0, 15, 30, 60, 240 and 360 minutes. The three samples were drawn pre- and post-membrane oxygenator and the polyvinyl chloride (PVC) tubing. A second bolus dose was administered 24 hours after the first in order to compare "new" and "old" circuits. This entire process was repeated a total of three times. The results show that acetaminophen concentrations do not change significantly over time, with consistent levels seen in both new and old circuits (N=9). Average old circuit concentrations were approximately two times greater than the average new circuit concentrations after the circuit was re-dosed at 24 hours. Drug sequestration in the circuit was not significant in any of the three sites measured. It appears that, while acetaminophen levels remain relatively constant over a six hour period, dosing adjustments may be required for use in a circuit beyond the initial 24 hour period, depending on physiologic clearance of the drug. Assuming a six-hour dosing interval, levels should remain constant.

Clinical and economic evidence for intravenous acetaminophen

Intravenous acetaminophen received United States Food and Drug Administration approval in November 2010 for the management of mild-to-moderate pain, management of moderate-to-severe pain with adjunctive opioid analgesics, and reduction of fever. Although intravenous acetaminophen generally improved pain relief and demonstrated opioid-sparing effects compared with placebo, it did not consistently reduce the frequency of opioid-related adverse events (e.g., postoperative nausea and vomiting). The safety and efficacy of intravenous acetaminophen as an antipyretic agent have been documented in adults and children; however, its cost is several-fold higher than that of the oral and rectal formulations. Although use of intravenous acetaminophen has reduced other postoperative resource utilization (e.g., hospital length of stay) in some studies outside the United States in patients undergoing abdominal surgery, a full economic evaluation in the United States has yet to be undertaken. In addition, its administration time (15-min infusion) and packaging (glass, single-use vial) have the potential to adversely affect patient flow in the postanesthesia care unit, create burden on patient care units, and lead to drug waste. Furthermore, 1 g of intravenous acetaminophen is formulated in 100 ml of solution, which may be an issue for patients with fluid restrictions. Given the clinical and economic evidence currently available, intravenous acetaminophen should not replace oral or rectal acetaminophen, but its use may be considered in a limited number of patients who cannot receive drugs orally and rectally and who cannot tolerate other parenteral nonopioid analgesic or antipyretic agents.