Paracetamol: new vistas of an old drug

Evaluation of Low Level Laser Therapy on Pain Perception Following Orthodontic Elastomeric Separation: A Randomized Controlled Trial

INTRODUCTION

Periodontal pain caused by elastomeric separators is a very common problem in the commencement of orthodontic treatment. Previous studies have shown good results in reducing this pain by Low Level Laser Therapy (LLLT) and different protocols of application have been suggested in the literature.

AIM

This trial aimed to evaluate LLLT on managing orthodontic pain caused by elastomeric separators and to compare single versus double irradiation in possible pain reduction.

MATERIALS AND METHODS

A clinical randomized compound (parallel-group and split-mouth design) trial was conducted on 36 patients between 12 and 26 years of age. Elastomeric separators were placed at the mesial and distal surfaces of the first molars in one jaw (upper or lower) for each patient and in only one side of the mouth (the other side served as the placebo side). The trial had two groups: the first group received single irradiation of LLLT [Gallium Aluminum Arsenide (GaAlAs): 830 nm, 4J/cm², 100mW] immediately after separators insertion, where as the second group received double irradiation immediately after separators insertion and after 24hours. All patients were instructed to rate the level of pain at 1, 6, 24, 48, 96 hours on a Visual Analog Scale (VAS). The student 't' tests, repeated measures ANOVA and LSD post-hoc tests were employed.

RESULTS

LLLT was successful in reducing post-separation pain when the experimental side was compared to the placebo side at all assessment times in each group (p<0.05). There were no statistically significant differences between single and double irradiation groups in terms of pain reduction (p>0.05).

CONCLUSION

GaAlAs LLLT application reduced early orthodontic pain caused by elastomeric separators by single or double irradiation.

Acetaminophen Increases Aldosterone Secretion While Suppressing Cortisol and Androgens: A Possible Link to Increased Risk of Hypertension

BACKGROUND

Acetaminophen (paracetamol) is a widely used analgesic and antipyretic drug. Potential side effects are of public health concern, and liver toxicity from acute overdose is well known. More recently, a regular use of acetaminophen has been associated with an increased risk of hypertension.

METHODS

We investigated effects of acetaminophen on steroidogenesis as a possible mechanism for the hypertensive action by using the human adrenocortical cell line, H295R. Cells were treated with 0.1, 0.5, and 1mM of acetaminophen for 24 hours, and secretion of steroids and gene expression of key steps in the steroidogenesis were investigated.

RESULTS

Progesterone and aldosterone secretion were increased dose dependently, while secretion of 17α-OH-progesterone and cortisol as well as dehydroepiandrosterone and androstenedione was decreased. CYP17α-hydroxylase activity, assessed by the ratio 17α-OH-progesterone/progesterone, and CYP17-lyase activity, assessed by the ratio androstenedione/17α-OH-progesterone, were both dose-dependently decreased by acetaminophen. No effects were revealed on cell viability. Treatment of cells with 0.5mM of acetaminophen did not cause any effects on the expression of 10 genes in the steroidogenic pathways.

CONCLUSIONS

The pattern of steroid secretion caused by acetaminophen can be explained by inhibition of CYP17A1 enzyme activity. A decreased secretion of glucocorticoids and androgens, as demonstrated by acetaminophen, would, in an in vivo situation, induce adrenocorticotropic hormone release via negative feedback in the hypothalamic-pituitary-adrenal axis and result in an upregulation of aldosterone secretion. Our results suggest a novel possible mechanism for acetaminophen-induced hypertension, which needs to be further elucidated in clinical investigations.

Influence of the Time of Intravenous Administration of Paracetamol on its Pharmacokinetics and Ocular Disposition in Rabbits

BACKGROUND AND OBJECTIVES

Paracetamol is one of the most common analgesics and antipyretics applied in health care. The aim of the study was to investigate the influence of the time-of-day administration on the paracetamol pharmacokinetics and its penetration into aqueous humour (AH).

METHODS

Rabbits were divided into three groups: I-receiving paracetamol at 08.00 h, II-receiving paracetamol at 16.00 h, and III-receiving paracetamol at 24.00 h. Paracetamol was administered intravenously at a single dose of 35 mg/kg. The concentrations of paracetamol and its metabolite (paracetamol glucuronide) in the plasma, as well as in AH were measured with the validated HPLC-UV method.

RESULTS

No significant differences in the pharmacokinetic parameters of paracetamol was observed. When the drug was administered at 24.00 h,  elimination half-life (t _1/2kel) of paracetamol glucuronide was longer than when the drug was administered 08.00 h (P = 0.0193). In addition, a statistically significant increase in the paracetamol glucuronide/paracetamol ratio was observed when the drug was administered at 08.00 vs. 16.00 h (P ≤ 0.0001) and 24.00 h (P ≤ 0.0001).

CONCLUSIONS

There was no chronobiological effect on the pharmacokinetic parameters of paracetamol.

Effects of Oxidative Stress and Testosterone on Pro-Inflammatory Signaling in a Female Rat Dopaminergic Neuronal Cell Line

Parkinson's disease, a progressive neurodegenerative disorder, is associated with oxidative stress and neuroinflammation. These pathological markers can contribute to the loss of dopamine neurons in the midbrain. Interestingly, men have a 2-fold increased incidence for Parkinson's disease than women. Although the mechanisms underlying this sex difference remain elusive, we propose that the primary male sex hormone, testosterone, is involved. Our previous studies show that testosterone, through a putative membrane androgen receptor, can increase oxidative stress-induced neurotoxicity in dopamine neurons. Based on these results, this study examines the role of nuclear factor κ B (NF-κB), cyclooxygenase-2 (COX2), and apoptosis in the deleterious effects of androgens in an oxidative stress environment. We hypothesize, under oxidative stress environment, testosterone via a putative membrane androgen receptor will exacerbate oxidative stress-induced NF-κB/COX2 signaling in N27 dopaminergic neurons, leading to apoptosis. Our data show that testosterone increased the expression of COX2 and apoptosis in dopamine neurons. Inhibiting the NF-κB and COX2 pathway with CAPE and ibuprofen, respectively, blocked testosterone's negative effects on cell viability, indicating that NF-κB/COX2 cascade plays a role in the negative interaction between testosterone and oxidative stress on neuroinflammation. These data further support the role of testosterone mediating the loss of dopamine neurons under oxidative stress conditions, which may be a key mechanism contributing to the increased incidence of Parkinson's disease in men compared with women.

Efficacy of intravenous paracetamol on pressor response in patients undergoing cesarean section under general anesthesia

BACKGROUND AND AIMS

Profound hemodynamic alterations due to stress and pain during endotracheal intubation may cause deleterious effects. The purpose of this study was to evaluate the effect of intravenous (IV) paracetamol on hemodynamic changes due to endotracheal intubation during cesarean section under general anesthesia.

MATERIAL AND METHODS

Random allocation of one hundred and ten patients in two groups (Group A - placebo and Group B - paracetamol), was achieved as per computer generated table. The placebo (normal saline) and paracetamol solutions looked identical as both were available in 100 ml piggy bags and were labeled as study drug. Infusion of the drug was given 1 h before surgery. Two baseline readings of heart rate, systolic blood pressure (BP), diastolic BP and mean BP were recorded before induction, and these readings were repeated during intubation. Detrimental effect on neonate was evaluated by Apgar score measured at 1 and 5 min after birth.

RESULTS

There were no significant demographic differences found between the two groups. Hemodyamic changes during intubation also did not differ between the two groups.

CONCLUSION

Administration of IV paracetamol 1 h before cesarean section has no significant effect in preventing hemodynamic changes at the time of endotracheal intubation.

Escape Mutations in NS4B Render Dengue Virus Insensitive to the Antiviral Activity of the Paracetamol Metabolite AM404

Despite the enormous disease burden associated with dengue virus infections, a licensed antiviral drug is lacking. Here, we show that the paracetamol (acetaminophen) metabolite AM404 inhibits dengue virus replication. Moreover, we find that mutations in NS4B that were previously found to confer resistance to the antiviral compounds NITD-618 and SDM25N also render dengue virus insensitive to AM404. Our work provides further support for NS4B as a direct or indirect target for antiviral drug development.

Acetaminophen Use for Fever in Children Associated with Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is characterized by persistent deficits in social communication and restrictive behavior, interests, and activities. Our previous case-control study showed that use of acetaminophen at age 12-18 months is associated with increased likelihood for ASD (OR 8.37, 95% CI 2.08-33.7). In this study, we again show that acetaminophen use is associated with ASD (p = 0.013). Because these children are older than in our first study, the association is reversed; fewer children with ASD vs. non-ASD children use acetaminophen as a "first choice" compared to "never use" (OR 0.165, 95% CI 0.045, 0.599). We found significantly more children with ASD vs. non- ASD children change to the use of ibuprofen when acetaminophen is not effective at reducing fever (p = 0.033) and theorize this change in use is due to endocannabinoid system dysfunction. We also found that children with ASD vs. non-ASD children are significantly more likely to show an increase in sociability when they have a fever (p = 0.037) and theorize that this increase is due to anandamide activation of the endocannabinoid system in ASD children with low endocannabinoid tone from early acetaminophen use. In light of this we recommend that acetaminophen use be reviewed for safety in children.

Pharmacokinetics of paracetamol in patients with chronic pancreatitis

BACKGROUND

Chronic pancreatitis (CP) is a progressive, irreversible disease causing damage of the gland. Abdominal pains are a typical symptom of pancreatitis both in the chronic and acute form. Paracetamol is one of analgesics used for treating mild or moderate pain. Functional and anatomical changes in the gastrointestinal tract caused by pancreatitis may influence on the pharmacokinetics of administered drugs.

METHODS

In the present study we analysed the pharmacokinetics of paracetamol after oral and intravenous administration to patients with CP. The patients were allocated to one of the two groups of the drug under study: I iv, intravenous administration of paracetamol 1000mg (n=17; mean [SD] age, 46.18 [13.78] years; and BMI, 22.03 [2.62]kg/m(2)) and II po, oral administration of paracetamol 1000mg (n=17; mean [SD] age, 48.29 [10.08] years; and BMI, 22.50 [2.92]kg/m(2). The plasma concentrations of paracetamol and its metabolite (glucuronide) were measured with the validated high-pressure liquid chromatography (HPLC) method with ultraviolet (UV) detection.

RESULTS

The main pharmacokinetic parameters for paracetamol after iv and po administration to patients with CP were as follows: Cmax, 19.00 [4.50] and Cmax, 9.26 [3.35]μg/ml; AUC0-t, 42.37 [13.92] and 36.68 [11.7]μg×h/mL, respectively. After iv and po administration the AUC ratio between the metabolite (glucuronide) and paracetamol was enhanced.

CONCLUSIONS

The research findings revealed that patients with chronic pancreatitis had lower concentrations of paracetamol. Therefore, it may be necessary to apply additional analgesic therapy. Moreover, we observed enhanced glucuronidation in our patients.

Pain Part 3: Acute Orofacial Pain

Acute trigeminal pain is a common presentation in the dental surgery, with a reported 22% of the US adult population experiencing orofacial pain more than once during a 6-month period. This article discusses the mechanisms underlying the pain experience, diagnosis and subsequent management of acute trigeminal pain, encompassing pre-, peri- and post-operative analgesia. The dental team spend most of their working lives managing patients and acute pain. The patient may present to the clinician in existing pain, which may often provide a diagnostic challenge. Prevention and managing intra-operative and post-surgical pain are implicit in providing your patient with optimum care. CPD/CLINICAL RELEVANCE: This paper aims to provide an overview of conditions that may present with acute orofacial pain and their management using the most recent evidence base. Intra-operative and post-surgical pain management are also scrutinized and evidence based treatment is recommended.

Phytochemical analysis, antimicrobial and antioxidant activities of Euphorbia golondrina L.C. Wheeler (Euphorbiaceae Juss.): an unexplored medicinal herb reported from Cameroon

This study aimed at determining the phytochemical constituents of Euphorbia golondrina L.C. Wheeler, an alien invasive medicinal herb that is used for the treatment of gastroenteritis related ailments, diabetes, conjunctivitis, gastritis, enterocolitis, tonsillitis, vaginitis, hemorrhoids, prostatism, warts and painful swellings by the Mundani people of the mount Bambouto Caldera in SouthWestern Cameroon, and to evaluate its in vitro antimicrobial and antioxidant activities. Susceptibility testing by agar well diffusion assay revealed good antibacterial activity with inhibition zone diameter of 20 ± 1.1 mm against Bacillus cereus followed by Staphylococcus aureus with inhibition zone diameter of 17 ± 1.6 mm which was significantly lower (P < 0.05) than the positive control (amoxicillin). None of the fungi was inhibited by the acetone extract of E. golondrina except Candida albicans wherein the zone of inhibition was not significantly different from that of the positive control (Amphotericin B). The ABTS scavenging activity of E. golondrina was higher than that of gallic acid and BHT at concentrations greater than 0.1 and 0.2 mg/mL respectively while at all concentrations, nitric oxide scavenging activity was higher than those of both rutin and vitamin C. GC–MS profile of E. golondrina steam distilled volatiles revealed that the plant has potent phytoconstituent classes such as sesquiterpenes, monoterpenes, alkaloids, phenolics and aromatic hydrocarbons. Among the 30 compounds identified, caryophyllene oxide (14.16 %), camphor (9.41 %) and phytol (5.75 %) were the major compounds. Further structural characterisation based on ¹H and ¹³C NMR is required to demonstrate structural integrity including correct stereochemistry. The current study partially justifies the ethnomedicinal uses of E. golondrina in Cameroon.

Comparison of the effects of treatment with celecoxib, loxoprofen, and acetaminophen on postoperative acute pain after arthroscopic knee surgery: A randomized, parallel-group trial

BACKGROUND

Selective cyclooxygenase-2 (COX-2) inhibitors, conventional non-selective nonsteroidal anti-inflammatory drugs (NSAIDs), and acetaminophen have been adopted for the relief of mild to moderate acute and chronic pain. However, it remains unclarified whether the therapeutic differences in pain sensation exist among these agents. The aim of this study was to compare the efficacy of different types of analgesic agents for postoperative acute pain management.

METHODS

A single-center, randomized, controlled study was performed in consecutive patients who underwent the second-look procedure with removal of internal fixation after anterior cruciate ligament reconstruction or arthroscopic meniscal repair/meniscectomy. Celecoxib (400 mg for the first dose and then 200 mg), loxoprofen (60 mg), or acetaminophen (600 mg) was orally administered from postoperative 3 h. The pain intensity on a 100-mm VAS scale and subjective assessment of therapeutic pain-relief were compared among these three treatment groups until postoperative 2 days. The acquired data were analyzed according to the per-protocol analysis principle.

RESULTS

A total of 432 patients were screened, and 160 were enrolled. The VAS score tended to decrease over time in all groups. There was a significant improvement in the pain score both at rest and on movement, and subjective impression in the celecoxib-treated group compared with acetaminophen at postoperative 2 days. On the other hand, loxoprofen resulted in the benefit only in the pain score at rest in comparison with acetaminophen. Any comparisons between celecoxib and loxoprofen showed insignificant differences throughout observations. No adverse effects were confirmed in each group.

CONCLUSIONS

These obtained findings in our dose setting conditions suggest that celecoxib and loxoprofen treatments were superior to acetaminophen in pain-relief, though the superiority of loxoprofen over acetaminophen was modest. Overall, selective COX-2 inhibitors including conventional NSAIDs seem to have a possible advantage in acute pain management of relatively less invasive surgery.

Acetaminophen from liver to brain: New insights into drug pharmacological action and toxicity

Acetaminophen (APAP) is a well-known analgesic and antipyretic drug. It is considered to be safe when administered within its therapeutic range, but in cases of acute intoxication, hepatotoxicity can occur. APAP overdose is the leading cause of acute liver failure in the northern hemisphere. Historically, studies on APAP toxicity have been focused on liver, with alterations in brain function attributed to secondary effects of acute liver failure. However, in the last decade the pharmacological mechanism of APAP as a cannabinoid system modulator has been documented and some articles have reported "in situ" toxicity by APAP in brain tissue at high doses. Paradoxically, low doses of APAP have been reported to produce the opposite, neuroprotective effects. In this paper we present a comprehensive, up-to-date overview of hepatic toxicity as well as a thorough review of both toxic and beneficial effects of APAP in brain.

Acetaminophen attenuates error evaluation in cortex

Acetaminophen has recently been recognized as having impacts that extend into the affective domain. In particular, double blind placebo controlled trials have revealed that acetaminophen reduces the magnitude of reactivity to social rejection, frustration, dissonance and to both negatively and positively valenced attitude objects. Given this diversity of consequences, it has been proposed that the psychological effects of acetaminophen may reflect a widespread blunting of evaluative processing. We tested this hypothesis using event-related potentials (ERPs). Sixty-two participants received acetaminophen or a placebo in a double-blind protocol and completed the Go/NoGo task. Participants' ERPs were observed following errors on the Go/NoGo task, in particular the error-related negativity (ERN; measured at FCz) and error-related positivity (Pe; measured at Pz and CPz). Results show that acetaminophen inhibits the Pe, but not the ERN, and the magnitude of an individual's Pe correlates positively with omission errors, partially mediating the effects of acetaminophen on the error rate. These results suggest that recently documented affective blunting caused by acetaminophen may best be described as an inhibition of evaluative processing. They also contribute to the growing work suggesting that the Pe is more strongly associated with conscious awareness of errors relative to the ERN.

Comparison of the analgesic effect of intravenous acetaminophen with that of flurbiprofen axetil on post-breast surgery pain: a randomized controlled trial

OBJECTIVE

Acetaminophen is known to be a relatively weak analgesic with fewer side effects than nonsteroidal anti-inflammatory drugs (NSAIDs). This study aimed to determine whether intravenous (iv) acetaminophen produces comparable analgesic effects to those of flurbiprofen (positive control drug), an intravenously injectable NSAID, after partial mastectomies. The primary outcome assessed was pain intensity during the first 24 h after the operation, and the secondary outcome was the satisfaction rating at discharge.

METHODS

After obtaining Institutional Ethics Committee approval, a series of 40 consecutive female patients who were scheduled for partial mastectomies were enrolled. Participants were randomly divided into two groups: an acetaminophen (1000 mg × 3) group (group A) and a flurbiprofen (50 mg × 3) group (group F). Each drug was administered 15 min before the end of surgery, and at 6 and 12 h after the operation. Postoperative pain was evaluated using a 100-mm visual analog scale (VAS) at 3, 6, and 24 h postoperatively. Satisfaction rating was evaluated on a 5-point scale (very good, good, well, bad, and very bad).

RESULTS

VAS scores (mm) with movement in groups A and F at 3, 6, and 24 h after the surgery were 22 vs. 28, 14 vs. 24, and 12 vs. 20.5 (median), respectively, with no significant differences between the two groups. Eighteen of 20 patients in group A and 20 of 20 patients in group F expressed a satisfaction rating of greater than good.

CONCLUSIONS

Acetaminophen produces an equivalent analgesic effect to flurbiprofen in post-partial mastectomy patients.

Options for perioperative pain management in neurosurgery

Moderate-to-severe pain following neurosurgery is common but often does not get attention and is therefore underdiagnosed and undertreated. Compounding this problem is the traditional belief that neurosurgical pain is inconsequential and even dangerous to treat. Concerns about problematic effects associated with opioid analgesics such as nausea, vomiting, oversedation, and increased intracranial pressure secondary to elevated carbon dioxide tension from respiratory depression have often led to suboptimal postoperative analgesic strategies in caring for neurosurgical patients. Neurosurgical patients may have difficulty or be incapable of communicating their need for analgesics due to neurologic deficits, which poses an additional challenge. Postoperative pain control should be a priority, because pain adversely affects recovery and patient outcomes. Inconsistent practices and the quality of current analgesic strategies for neurosurgical patients still leave room for improvement. Given the complexity of postoperative pain management for these patients, multimodal strategies are often required to optimize pain control and at the same time limit undesired side effects.

Characterizing protein modifications by reactive metabolites using magnetic bead bioreactors and LC-MS/MS

We report here label-free metabolite-protein adduct detection and identification employing magnetic beads coated with metabolic enzymes as bioreactors to generate metabolites and possible metabolite-protein adducts for analysis by liquid chromatography-tandem mass spectrometry.

Metabolism of AM404 From Acetaminophen at Human Therapeutic Dosages in the Rat Brain

Background:

Acetaminophen, an analgesic and antipyretic drug, has been used clinically for more than a century. Previous studies showed that acetaminophen undergoes metabolic transformations to form an analgesic compound, N-(4-hydroxyphenyl) arachidonamide (AM404), in the rodent brain. However, these studies were performed with higher concentrations of acetaminophen than are used in humans.

Objectives:

The aim of the present study was to examine the metabolism of AM404 from acetaminophen in the rat brain at a concentration of 20 mg/kg, which is used in therapeutic practice in humans, and to compare the pharmacokinetics between them.

Materials and Methods:

We used rat brains to investigate the metabolism of AM404 from acetaminophen at concentrations (20 mg/kg) used in humans. In addition, we determined the mean pharmacokinetic parameters for acetaminophen and its metabolites, including AM404.

Results:

The maximum plasma concentrations of acetaminophen and AM404 in the rat brain were 15.8 µg/g and 150 pg/g, respectively, with corresponding AUC_0-2h values of 8.96 μg hour/g and 117 pg hour/g. The t_max for both acetaminophen and AM404 was 0.25 hour.

Conclusions:

These data suggest that AM404’s concentration-time profile in the brain is similar to those of acetaminophen and its other metabolites. Measurement of blood acetaminophen concentration seems to reflect the concentration of the prospective bioactive substance, AM404.

Simultaneous determination of ciprofloxacin and paracetamol by adsorptive stripping voltammetry using copper zinc ferrite nanoparticles modified carbon paste electrode

Development of copper zinc ferrite nanoparticles modified carbon paste electrode for the simultaneous determination of ciprofloxacin and paracetamol using adsorptive stripping differential pulse voltammetry.

A Mechanism-Based Approach to the Management of Osteoarthritis Pain

Pain from osteoarthritis (OA) affects millions of people worldwide, yet treatments are limited to acetaminophen, NSAIDs, physical therapy, and ultimately, surgery when there is significant disability. In recent years, our understanding of pain pathways in OA has developed considerably. Though joint damage and inflammation play a significant role in pain generation, it is now understood that both central and peripheral nervous system mechanisms exacerbate symptoms. Evolving management strategies for OA address central factors (e.g., sleep difficulties, catastrophizing, and depression) with treatments such as cognitive behavioral therapy and exercise. In addition, emerging data suggest that antibodies against peripheral signaling neuropeptides, such as nerve growth factor-1 (NGF-1), may significantly alleviate pain. However, concerns regarding potential adverse effects, such as rapidly progressive OA, still remain. A nuanced understanding is essential if we are to make headway in developing more effective treatments for OA.

Effect of Acetaminophen Alone and in Combination with Morphine and Tramadol on the Minimum Alveolar Concentration of Isoflurane in Rats

Background

It has been observed that acetaminophen potentiates the analgesic effect of morphine and tramadol in postoperative pain management. Its capacity as an analgesic drug or in combinations thereof to reduce the minimum alveolar concentration (MAC) of inhalational anesthetics represents an objective measure of this effect during general anesthesia. In this study, the effect of acetaminophen with and without morphine or tramadol was evaluated on the isoflurane MAC.

Methods

Forty-eight male Wistar rats were anesthetized with isoflurane in oxygen. MAC_ISO was determined from alveolar gas samples at the time of tail clamping without the drug, after administering acetaminophen (300 mg/kg), morphine (3 mg/kg), tramadol (10 mg/kg), acetaminophen (300 mg/kg) + morphine (3 mg/kg), and acetaminophen (300 mg/kg) + tramadol (10 mg/kg).

Results

The control and acetaminophen groups did not present statistically significant differences (p = 0.98). The values determined for MAC_ISO after treatment with acetaminophen + morphine, acetaminophen + tramadol, morphine, and tramadol were 0.98% ± 0.04%, 0.99% ± 0.009%, 0.97% ± 0.02%, and 0.99% ± 0.01%, respectively.

Conclusions

The administration of acetaminophen did not reduce the MAC of isoflurane and did not potentiate the reduction in MAC_ISO by morphine and tramadol in rats, and therefore does not present a sparing effect of morphine or tramadol in rats anesthetized with isoflurane.

Prediction of color changes in acetaminophen solution using the time-temperature superposition principle

A prediction method for color changes based on the time-temperature superposition principle (TTSP) was developed for acetaminophen solution. Color changes of acetaminophen solution are caused by the degradation of acetaminophen, such as hydrolysis and oxidation. In principle, the TTSP can be applied to only thermal aging. Therefore, the impact of oxidation on the color changes of acetaminophen solution was verified. The results of our experiment suggested that the oxidation products enhanced the color changes in acetaminophen solution. Next, the color changes of acetaminophen solution samples of the same head space volume after accelerated aging at various temperatures were investigated using the Commission Internationale de l'Eclairage (CIE) LAB color space (a*, b*, L* and ΔE*ab), following which the TTSP was adopted to kinetic analysis of the color changes. The apparent activation energies using the time-temperature shift factor of a*, b*, L* and ΔE*ab were calculated as 72.4, 69.2, 72.3 and 70.9 (kJ/mol), respectively, which are similar to the values for acetaminophen hydrolysis reported in the literature. The predicted values of a*, b*, L* and ΔE*ab at 40 °C were obtained by calculation using Arrhenius plots. A comparison between the experimental and predicted values for each color parameter revealed sufficiently high R(2) values (>0.98), suggesting the high reliability of the prediction. The kinetic analysis using TTSP was successfully applied to predicting the color changes under the controlled oxygen amount at any temperature and for any length of time.

Fever and sickness behavior: Friend or foe?

Fever has been recognized as an important symptom of disease since ancient times. For many years, fever was treated as a putative life-threatening phenomenon. More recently, it has been recognized as an important part of the body's defense mechanisms; indeed at times it has even been used as a therapeutic agent. The knowledge of the functional role of the central nervous system in the genesis of fever has greatly improved over the last decade. It is clear that the febrile process, which develops in the sick individual, is just one of many brain-controlled sickness symptoms. Not only will the sick individual appear "feverish" but they may also display a range of behavioral changes, such as anorexia, fatigue, loss of interest in usual daily activities, social withdrawal, listlessness or malaise, hyperalgesia, sleep disturbances and cognitive dysfunction, collectively termed "sickness behavior". In this review we consider the issue of whether fever and sickness behaviors are friend or foe during: a critical illness, the common cold or influenza, in pregnancy and in the newborn. Deciding whether these sickness responses are beneficial or harmful will very much shape our approach to the use of antipyretics during illness.

AtomicChargeCalculator: interactive web-based calculation of atomic charges in large biomolecular complexes and drug-like molecules

Background

Partial atomic charges are a well-established concept, useful in understanding and modeling the chemical behavior of molecules, from simple compounds, to large biomolecular complexes with many reactive sites.

Results

This paper introduces AtomicChargeCalculator (ACC), a web-based application for the calculation and analysis of atomic charges which respond to changes in molecular conformation and chemical environment. ACC relies on an empirical method to rapidly compute atomic charges with accuracy comparable to quantum mechanical approaches. Due to its efficient implementation, ACC can handle any type of molecular system, regardless of size and chemical complexity, from drug-like molecules to biomacromolecular complexes with hundreds of thousands of atoms. ACC writes out atomic charges into common molecular structure files, and offers interactive facilities for statistical analysis and comparison of the results, in both tabular and graphical form.

Conclusions

Due to high customizability and speed, easy streamlining and the unified platform for calculation and analysis, ACC caters to all fields of life sciences, from drug design to nanocarriers. ACC is freely available via the Internet at http://ncbr.muni.cz/ACC.

Electronic supplementary material

The online version of this article (doi:10.1186/s13321-015-0099-x) contains supplementary material, which is available to authorized users.

Chromatography as Method for Analytical Confirmation of Paracetamol in Postmortem Material Together with Psychoactive Substances

Introduction:

Paracetamol (Acetaminophen) in addition to aspirin is the most commonly used analgesic and antipyretic medication by millions of patients worldwide. It is an example that paracetamol as medicine that in the world is provided without a doctor’s prescription, can lead to death. Today paracetamol became an integral part of a heroin mixture and is very popular at the street market. The main reason for this is that it can be obtained without a prescription, it is cheap, and by most people well tolerated without side effects. It is probably used for “cutting” the pure heroin, as it says in the jargon, and in that manner from small amount of pure drug is obtained greater amount, which is then sold on the street. The goal is to identify presence of paracetamol, by analytical method of gas chromatography mass spectrometer (GC-MS) in postmortem material together with psychoactive substances.

Material and methods:

For chemical-toxicological analysis is used biological material collected trough autopsy of 20 deceased people, suspected to have died due to psychoactive substance overdose. All received samples are stored at -20 ° C until analysis at our laboratory. From processed 47 samples that were analyzed in the period from 2014 to 2015, 19 are blood samples, urine 19, 3 samples of stomach contents, and 6 samples of bile content. Deceased were middle-aged, of which only 7 were female. The tested samples were processed according to two methods of extraction. Extraction by XAD-2 resin, and the extraction by the method of salting out with sodium tungstate. Extracts of the samples were then dissolved in chloroform and continued analysis at the analytical instrument. Identification of the paracetamol presence, in the test biological samples is demonstrated by the technique of gas chromatography with mass spectometry (hereinafter referred to as GC-MS). The technique of GC-MS is a selective, sensitive and reliable, and is therefore considered a “gold standard” for determining the drug, and the drug substance. Used GC-MS instrument was an Agilent 7890A with helium as the carrier gas.

Results:

The analysis of blood samples, urine, bile and stomach contents, obtained after the autopsy of deceased persons, by using gas chromatography with mass spectrometry, in analytical manner confirmed the fact that paracetamol is a very common component of psychoactive substances poisoning. In our assay of samples we detected psychoactive substances (heroin, codeine, morphine, sertraline, diazepam), and almost all were found in the combination with paracetamol, indicating the poor quality of illicit drugs sold on the market.

Discussion:

Paracetamol (Acetaminophen) is a very common component in mixtures of street drugs. Such mixtures almost anyone can afford, but the very quality of these drugs has become extremely low, because it does not sell the pure substance, but is mixed with various medications. According to research Pantazia et al. the heroin mixture proportion of the heroin is very small so a lot of that mixture has only 3% of heroin, a large number of cases can be only 1% of pure heroin. Most of the time it replaces caffeine and paracetamol. According to the Risser et al. reason why acetaminophen component is present in these mixtures is because it can be purchased without a prescription, it is cheap, well tolerated by most people and shows no side effects.

Conclusion:

When we talk about illegal drugs, we must emphasize the fact that there is no quality control, or the composition of the drug. The composition of the drug purchased on the black market is still unknown to potential user. While reaching the final drug users it pass through many hands, and at each step something is added to increase earnings. Most often present additives or impurities in narcotic drugs that are added are caffeine, ephedrine, acetaminophen, acetylsalicylic acid (aspirin) and additives such as powders, cement and chalk.

Non-Steroid Anti-Inflammatory Drugs Are Better than Acetaminophen on Fever Control at Acute Stage of Fracture

In addition to adequate surgical fixation and an aggressive rehabilitation program, pain relief is one of the most critical factors in the acute stage of fracture treatment. The most common analgesics are nonsteroid anti-inflammatory drugs and Acetaminophen, both of which relieve pain and reduce body temperature. In clinical experiences, they exhibit effective pain control; however, their influence on body temperature remains controversial. This study is aimed at determining the effects of analgesics at the acute stage of traumatic fracture by performing a clinical retrospective study of patients with fractures and a fracture animal model. The retrospective study revealed that, in the acetaminophen group, the mean value of postmedication body temperature (BT) was significantly higher than that of the premedication BT. The change in BT was highly related with the medication rather than other risk factors. Forty eight 12-week-old male Wistar rats were divided into 6 groups: a control group, fracture group, fracture-Acetaminophen group, Acetaminophen group, fracture-Arcoxia group, and Arcoxia group. Fracture rats were prepared by breaking their unilateral tibia and fibula. Their inflammation conditions were evaluated by measuring their serum cytokine level and their physiological status was evaluated by estimating their central temperature, heart rate, and mean blood pressure. The hepatic adverse effects were assessed by measuring the serum levels of aspartate aminotransferase (sGOT) and alanine aminotransferase (sGPT). The central temperature in the fracture-Acetaminophen group exceeded that in the groups fed normal saline water or Arcoxia. Accumulated hepatic injury was presented as steadily ascending curves of sGOT and sGPT. Inflammation-related cytokine levels were not higher in the Acetaminophen fracture group and were significantly lower in the fracture-Arcoxia group. Fever appeared to be aggravated by acetaminophen and more related to the elevation of hepatic enzymes than to the change in the inflammation-related cytokines. We suggest that acetaminophen may aggravate fever at the acute stage of fracture. This response is highly related to the accumulated and exacerbated side effects of hepatitis that are caused by the medication and trauma.

High-Throughput Cytotoxicity Testing System of Acetaminophen Using a Microfluidic Device (MFD) in HepG2 Cells

A lab-on-a-chip (LOC) is a microfluidic device (MFD) that integrates several lab functions into a single chip of only millimeters in size. LOC provides several advantages, such as low fluidic volumes consumption, faster analysis, compactness, and massive parallelization. These properties enable a microfluidic-based high-throughput drug screening (HTDS) system to acquire cell-based abundant cytotoxicity results depending on linear gradient concentration of drug with only few hundreds of microliters of the drug. Therefore, a microfluidic device was developed containing an array of eight separate microchambers for cultivating HepG2 cells to be exposed to eight different concentrations of acetaminophen (APAP) through a diffusive-mixing-based concentration gradient generator. Every chamber array with eight different concentrations (0, 5.7, 11.4, 17.1, 22.8, 28.5, 34.2, or 40 mM) APAP had four replicating cell culture chambers. Consequently, 32 experimental results were acquired with a single microfluidic device experiment. The microfluidic high-throughput cytotoxicity device (μHTCD) and 96-well culture system showed comparable cytotoxicity results with increasing APAP concentration of 0 to 40 mM. The HTDS system yields progressive concentration-dependent cytotoxicity results using minimal reagent and time. Data suggest that the HTDS system may be applicable as alternative method for cytotoxicity screening for new drugs in diverse cell types.

Drug induced hypertension--An unappreciated cause of secondary hypertension

Most patients with hypertension have essential hypertension or well-known forms of secondary hypertension, such as renal disease, renal artery stenosis, or common endocrine diseases (hyperaldosteronism or pheochromocytoma). Physicians are less aware of drug induced hypertension. A variety of therapeutic agents or chemical substances may increase blood pressure. When a patient with well controlled hypertension is presented with acute blood pressure elevation, use of drug or chemical substance which increases blood pressure should be suspected. Drug-induced blood pressure increases are usually minor and short-lived, although rare hypertensive emergencies associated with use of certain drugs have been reported. Careful evaluation of prescription and non-prescription medications is crucial in the evaluation of the hypertensive individual and may obviate the need for expensive and unnecessary evaluations. Discontinuation of the offending agent will usually achieve adequate blood pressure control. When use of a chemical agent which increases blood pressure is mandatory, anti-hypertensive therapy may facilitate continued use of this agent. We summarize the therapeutic agents or chemical substances that elevate blood pressure and their mechanisms of action.

Single crystal XRD, vibrational and quantum chemical calculation of pharmaceutical drug paracetamol: A new synthesis form

The common house hold pharmaceutical drug, paracetamol (PAR), has been synthesized from 4-chloroaniline as a first ever report. After the synthesis, good quality single crystals were obtained for slow evaporation technique under the room temperature. The crystal and molecular structures were re-determined by the single crystal X-ray diffraction. The vibrational spectral measurements were carried out using FT-IR and FT-Raman spectroscopy in the range of 4000-400 cm(-1). The single crystal X-ray studies shows that the drug crystallized in the monoclinic system polymorph (Form-I). The crystal packing is dominated by N-H⋯O and O-H⋯O classical hydrogen bonds. The ac diagonal of the unit cell features two chain C(7) and C(9) motifs running in the opposite directions. These two chain motifs are cross-linked to each other to form a ring R4(4)(22) motif and a chain C2(2)(6) motif which is running along the a-axis of the unit cell. Along with the classical hydrogen bonds, the methyl group forms a weak C-H⋯O interactions in the crystal packing. It offers the support for molecular assembly especially in the hydrophilic regions. Further, the strength of the hydrogen bonds are studied the shifting of vibrational bands. Geometrical optimizations of the drug molecule were done by the Density Functional Theory (DFT) using the B3LYP function and Hartree-Fock (HF) level with 6-311++G(d,p) basis set. The optimized molecular geometry and computed vibrational spectra are compared with experimental results which show significant agreement. The factor group analysis of the molecule was carried out by the various molecular symmetry, site and factor group species using the standard correlation method. The Natural Bond Orbital (NBO) analysis was carried out to interpret hyperconjugative interaction and intramolecular charge transfer (ICT). The chemical softness, chemical hardness, electro-negativity, chemical potential and electrophilicity index of the molecule were found out first time by HOMO-LUMO plot. The frontier orbitals shows lower band gap values signify the possible biological/pharmaceutical activity of the molecule. The thermodynamical properties are also obtained from the calculated frequencies of the optimized structures.

The protective effects of aqueous extract of Carica papaya seeds in paracetamol induced nephrotoxicity in male wistar rats

BACKGROUND

Oxidative stress plays a crucial role in the development of drug induced nephrotoxicity. The study aimed to determine the nephroprotective and ameliorative effects of Carica papaya seed extract in paracetamol-induced nephrotoxicity in rats.

OBJECTIVES

To carry out phytochemical screening of Carica papaya, measure serum urea, creatinine and uric acid and describe the histopathological status of the kidneys in the treated and untreated groups.

METHODS

Phytochemical screening of the extract was done. Thirty two adult male Wistar rats were divided into four groups (n= 8 in each group). Group A (control) animals received normal saline for seven days, group B (paracetamol group) received normal saline, and paracetamol single dose on the 8th day. Group C received Carica papaya extract (CPE) 500 mg/kg, and paracetamol on the 8th day, while group D, rats were pretreated with CPE 750 mg/kg/day,and paracetamol administration on the 8th day. Samples of kidney tissue were removed for histopathological examination.

RESULTS

Screening of Carica papaya showed presence of nephroprotective pytochemicals. Paracetamol administration resulted in significant elevation of renal function markers. CPE ameliorated the effect of paracetamol by reducing the markers as well as reversing the paracetamol-induced changes in kidney architecture.

CONCLUSION

Carica papaya contains nephroprotective phytochemicals and may be useful in preventing kidney damage induced by paracetamol.

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.

[Pediatric perioperative systemic pain therapy: Austrian interdisciplinary recommendations on pediatric perioperative pain management]

BACKGROUND

Many analgesics used in adult medicine are not licensed for pediatric use. Licensing limitations do not, however, justify that children are deprived of a sufficient pain therapy particularly in perioperative pain therapy. The treatment is principally oriented to the strength of the pain. Due to the degree of pain caused, intramuscular and subcutaneous injections should be avoided generally.

NON-OPIOIDS

The basis of systemic pain therapy for children are non-opioids and primarily non-steroidal anti-inflammatory drugs (NSAIDs). They should be used prophylactically. The NSAIDs are clearly more effective than paracetamol for acute posttraumatic and postoperative pain and additionally allow economization of opioids. Severe side effects are rare in children but administration should be carefully considered especially in cases of hepatic and renal dysfunction or coagulation disorders. Paracetamol should only be taken in pregnancy and by children when there are appropriate indications because a possible causal connection with bronchial asthma exists. To ensure a safe dosing the age, body weight, duration of therapy, maximum daily dose and dosing intervals must be taken into account. Dipyrone is used in children for treatment of visceral pain and cholic. According to the current state of knowledge the rare but severe side effect of agranulocytosis does not justify a general rejection for short-term perioperative administration.

OPIOIDS

In cases of insufficient analgesia with non-opioid analgesics, the complementary use of opioids is also appropriate for children of all age groups. They are the medication of choice for episodes of medium to strong pain and are administered in a titrated form oriented to effectiveness. If severe pain is expected to last for more than 24 h, patient-controlled anesthesia should be implemented but requires a comprehensive surveillance by nursing personnel.

KETAMINE

Ketamine is used as an adjuvant in postoperative pain therapy and is recommended for use in pediatric sedation and analgosedation.

Biocatalytic approaches applied to the synthesis of nucleoside prodrugs

Nucleosides are valuable bioactive molecules, which display antiviral and antitumour activities. Diverse types of prodrugs are designed to enhance their therapeutic efficacy, however this strategy faces the troublesome selectivity issues of nucleoside chemistry. In this context, the aim of this review is to give an overview of the opportunities provided by biocatalytic procedures in the preparation of nucleoside prodrugs. The potential of biocatalysis in this research area will be presented through examples covering the different types of nucleoside prodrugs: nucleoside analogues as prodrugs, nucleoside lipophilic prodrugs and nucleoside hydrophilic prodrugs.

Preventive effect of intrathecal paracetamol on spinal cord injury in rats

Background:

Ischemic injury of the spinal cord during the surgical repair of thoracoabdominal aortic aneurysms might lead to paraplegia. Although a number of different mechanisms have been proposed, the exact cause of paraplegia has remained unknown, hampering the development of effective pharmacologic or other strategies for prevention of this condition. A number of studies suggested that cyclooxygenases (COX) contribute to neural breakdown; thus, COX inhibitors might reduce injury.

Objectives:

We aimed to assess the preventive effect of intrathecal (IT) pretreatment with paracetamol on spinal cord injury in a rat model.

Materials and Methods:

This experimental study was performed in Ataturk University Animal Research Laboratory Center, Erzurum, Turkey. Adult male Wistar rats were randomly allocated to three experimental groups (n = 6) to receive IT physiologic saline (controls), 50 µg of paracetamol, or 100 µg paracetamol one hour before induction of spinal cord ischemia. Six other rats were considered as the sham group. For the assessment of ischemic injury, motor functions of the hind limbs and histopathologic changes of the lumbar spinal cord were evaluated. Additional 20 rats were divided into two equal groups for the second part of the study where the survival rates were recorded in controls and in animals receiving 100 µg of paracetamol during the 28-day observation period.

Results:

Pretreatment with 100 µg of paracetamol resulted in a significant improvement in motor functions and histopathologic findings (P < 0.05). Despite a higher rate of survival in 100 µg of paracetamol group (70%) at day 28, the difference was not statistically significant in comparison with controls.

Conclusions:

Our results suggest a protective effect of pretreatment with IT paracetamol on ischemic spinal cord injury during thoracolumbar aortic aneurysm surgery.

Electroencephalography and analgesics

To assess centrally mediated analgesic mechanisms in clinical trials with pain patients, objective standardized methods such as electroencephalography (EEG) has many advantages. The aim of this review is to provide the reader with an overview of present findings in analgesics assessed with spontaneous EEG and evoked brain potentials (EPs) in humans. Furthermore, EEG methodologies will be discussed with respect to translation from animals to humans and future perspectives in predicting analgesic efficacy. We searched PubMed with MeSH terms 'analgesics', 'electroencephalography' and 'evoked potentials' for relevant articles. Combined with a search in their reference lists 15 articles on spontaneous EEG and 55 papers on EPs were identified. Overall, opioids produced increased activity in the delta band in the spontaneous EEG, but increases in higher frequency bands were also seen. The EP amplitudes decreased in the majority of studies. Anticonvulsants used as analgesics showed inconsistent results. The N-methyl-D-aspartate receptor antagonist ketamine showed an increase in the theta band in spontaneous EEG and decreases in EP amplitudes. Tricyclic antidepressants increased the activity in the delta, theta and beta bands in the spontaneous EEG while EPs were inconsistently affected. Weak analgesics were mainly investigated with EPs and a decrease in amplitudes was generally observed. This review reveals that both spontaneous EEG and EPs are widely used as biomarkers for analgesic drug effects. Methodological differences are common and a more uniform approach will further enhance the value of such biomarkers for drug development and prediction of treatment response in individual patients.

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.

Intravenous acetaminophen in bariatric surgery: effects on opioid requirements

BACKGROUND

Opioids are commonly used after bariatric surgery for pain control because of their potent analgesic effects. Nevertheless, the morbidly obese patient has increased risk for developing adverse effects produced by opioids (such as sedation, apnea, hypoxemia, ileus, and vomiting). Intravenous acetaminophen (IVA) has been evaluated in some specialties showing a reduction in opioid consumption. The purpose of this study was to evaluate the effect on opioid consumption when IVA is administered in bariatric surgery patients.

MATERIAL AND METHODS

A retrospective study was performed in patients who underwent bariatric surgery. Group A included those patients who received IVA perioperatively and group B those who did not. The amount of opioids administered was calculated and compared for each group.

RESULTS

Group A included 38 cases (44.7%) and group B included 47 cases (55.3%). A comparison was performed in terms of age (P = 0.349), body mass index (P = 0.311), gender (P = 0.890), American Society of Anesthesiologist score (P = 0.438), total surgical time (P = 0.497), perioperative complications (P = 0.786), number of procedures per surgeon (P = 0.08), and type of surgical procedure (P ≤ 0.01). Group A had a mean 24-h total opioid dose of 99.5 mg, whereas group B of 164.6 mg (P = 0.018). Group A received 39.5% less opioids than group B. A post hoc analysis determined a statistical power of 0.74.

CONCLUSIONS

IVA used perioperatively can decrease opioid consumption in patients after bariatric surgery. Randomized trials are needed to corroborate these results.

Paracetamol: a review with specific focus on the haemodynamic effects of intravenous administration

Paracetamol is one of the most commonly used drugs worldwide with non-prescription sales exceeding 25 thousand million doses per year in the United States of America. The haemodynamic effects of the intravenous paracetamol formulations are largely understudied. There is an emerging body of evidence suggesting that intravenous paracetamol may cause iatrogenic hypotension. Little is known as to the mechanisms of this phenomenon or if intravenous paracetamol indeed does cause hypotension. As paracetamol has negligible solubility in aqueous solutions, many of the commercially available intravenous formulations contain mannitol (up to 3.91 g/100 mL paracetamol) as a stabilising ingredient. It is unknown if mannitol is a contributing factor in the observed hypotension. In this review, we outline the development of paracetamol's current intravenous formulations, describe the composition of these formulations, and overview the literature pertaining to the proposed phenomenon of paracetamol-induced altered hypotension. Understanding the pharmacokinetic and pharmacodymanic properties of intravenous paracetamol may have important clinical implications for vulnerable patients in subgroups where haemodynamic stability is at risk such as those undergoing elective and emergency surgery.