A randomized, double-blind crossover trial of paracetamol 1000 mg four times daily vs ibuprofen 600 mg: effect on swelling and other postoperative events after third molar surgery

Paracetamol suppresses neutrophilic oxygen radicals through competitive inhibition and scavenging

Neutrophils, pivotal cells of innate and adaptive immune responses, employ reactive oxygen species (ROS) to combat pathogens and control gene expression. Paracetamol (acetaminophen) is widely used as an analgesic and antipyretic medication, yet its precise mechanisms of action are not yet fully understood. Here, we investigate the impact of both ingested and in-vitro paracetamol on neutrophil ROS activity, using flow cytometry and antioxidant assays. Our studies reveal that paracetamol significantly suppresses ROS activity ex-vivo in the short term. Additionally, both paracetamol and its metabolite N-acetyl-p-benzoquinone imine exhibited direct in vitro antioxidant effects, and paracetamol suppressed neutrophil extracellular trap formation ex vivo. These findings suggest a connection between paracetamol use and altered neutrophil responses, with potential implications for use in some patient groups, such as immunocompromised individuals. Further investigation into paracetamol's effects on neutrophil antimicrobial functions is warranted to elucidate possible risks, particularly when taken frequently or in conjunction with other treatments such as vaccinations.

Effect of Preemptive Analgesia on Pain Perception in Children: A Randomized Controlled Trial

Background

Efforts have been made to minimize pain, prevent the development of needle fear, and promote positive experiences for children. The present study is designed to evaluate the effect of premedication with Ibugesic Plus before the administration of local anesthesia and extraction in children.

Aim

The aim of the study is to assess the efficacy of preemptive analgesia on pain perception during local anesthesia administration and extraction in pediatric patients.

Materials and methods

A total of 104 patients aged 7-10 years were selected who needed primary molar extraction. Group -Ibugesic Plus syrup was given 30 minutes prior to extraction. Group II-Placebo solution (B-Folcin syrup) was given 30 minutes prior to extraction. Pain level, pulse rate, and SpO2 were assessed using the Wong-Baker Faces Pain Rating Scale (WBFS) and pulse oximeter after injection, after extraction, and postoperatively.

Results

The highest scores of pain were recorded after the time of injection and extraction. The patients who received preemptive analgesics (group I) reported significantly less pain than the placebo group (group II) at the time immediately after injection, after extraction, and 2 hours after extraction.

Conclusion

The present study showed that preemptive analgesic administration may be considered a routine and rational pain management strategy in primary tooth extraction procedures in children.

Clinical significance

Preemptive analgesia can be given to patients prior to dental procedures to reduce postoperative pain.

How to cite this article

Virda M, Panda A, Kataria K. Effect of Preemptive Analgesia on Pain Perception in Children: A Randomized Controlled Trial. Int J Clin Pediatr Dent 2024;17(8):913-917.

Assessment of the pre-emptive effect of photobiomodulation in the postoperative period of impacted lower third molar extractions: A randomized, controlled, double-blind study protocol

Photobiomodulation is a safe option for controlling pain, edema, and trismus when applied postoperatively in third molar surgery. However, administration prior to surgery has been under-explored. This study aims to explore the effectiveness of pre-emptive photobiomodulation in reducing postoperative edema in impacted lower third molar extractions. Two groups of healthy individuals undergoing tooth extraction will be randomly assigned: Control group receiving pre-emptive corticosteroid and simulated photobiomodulation, and Photobiomodulation Group receiving intraoral low-intensity laser and extraoral LED cluster application. The primary outcome will be postoperative edema after 48 h. The secondary outcomes will be pain, trismus dysphagia, and analgesic intake (paracetamol). These outcomes will be assessed at baseline as well as two and seven days after surgery. Adverse effects will be recorded. Data will be presented as means ± SD and a p-value < 0.05 will be indicative of statistical significance.

Three-dimensional facial swelling evaluation of pre-operative single-dose of prednisone in third molar surgery: a split-mouth randomized controlled trial

BACKGROUND

Facial swelling, pain, and trismus are the most common postoperative sequelae after mandibular third molar (M3M) surgery. Corticosteroids are the most used drugs to reduce the severity of inflammatory symptoms after M3M surgery. This study aimed to evaluate the effect of a single pre-operative dose of prednisone on pain, trismus, and swelling after M3M surgery.

METHODS

This study was designed as a split-mouth randomized, controlled, triple-blind trial with two treatment groups, prednisone (PG) and control (CG). All the parameters were assessed before the extraction (T0), two days (T1), and seven days after surgery (T2). Three-dimensional evaluation of facial swelling was performed with Bellus 3D Face App. A visual analogue scale (VAS) was used to assess pain. The maximum incisal distance was recorded with a calibrated rule to evaluate the trismus. The Shapiro-Wilk test was used to evaluate the normal distribution of each variable. To compare the two study groups, the analysis of variance was performed using a two-tailed Student t-test for normal distributions. The level of significance was set at a = 0.05. Statistical analysis was conducted using the software STATA (STATA 11, StataCorp, College Station, TX).

RESULTS

Thirty-two patients were recruited with a mean age of 23.6 ± 3.7 years, with a male-to-female ratio of 1:3. A total of 64 M3Ms (32 right and 32 left) were randomly assigned to PG or CG. Surgery time recorded a mean value of 15.6 ± 3.7 min, without statistically significant difference between the groups. At T1, PG showed a significantly lower facial swelling compared to CG (PG: 3.3 ± 2.1 mm; CG: 4.2 ± 1.7 mm; p = 0.02). Similar results were recorded comparing the groups one week after surgery (PG: 1.2 ± 1.2; CG: 2.1 ± 1.3; p = 0.0005). All patients reported a decrease in facial swelling from T1 to T2 without differences between the two groups. At T1, the maximum buccal opening was significantly reduced than T0, and no difference between PG (35.6 ± 8.2 mm) and CG (33.7 ± 7.3 mm) (p > 0.05) was shown. Similar results were reported one week after surgery (PG: 33.2 ± 14.4 mm; CG: 33.7 ± 13.1 mm; p > 0.05). PG showed significantly lower pain values compared to CG, both at T1 (PG: 3.1 ± 1.5; CG: 4.6 ± 1.8; p = 0.0006) and T2 (PG: 1.0 ± 0.8; CG: 1.9 ± 1.4; p = 0.0063).

CONCLUSION

Our results showed that pre-operative low-dose prednisone administration could reduce postoperative sequelae by improving patient comfort after M3M surgery and reducing facial swelling two days and one week after surgical procedures.

TRIAL REGISTRATION

www.

CLINICALTRIALS

gov - NCT05830747 retrospectively recorded-Date of registration: 26/04/2023.

Analgesic effect of oral paracetamol 1000 mg/ibuprofen 400 mg, paracetamol 1000 mg/codeine 60 mg, paracetamol 1000 mg/ibuprofen 400 mg/codeine 60 mg, or placebo on acute postoperative pain: a single-dose, randomized, and double-blind study

PURPOSE

Combining analgesics with different mechanisms of action may increase the analgesic efficacy. The multidimensional pharmacodynamic profiles of ibuprofen 400 mg/paracetamol 1000 mg, ibuprofen 400 mg/paracetamol 1000 mg/codeine 60 mg, and paracetamol 1000 mg/codeine 60 mg and placebo were compared.

METHODS

A randomized, double-blind, placebo-controlled, parallel-group, single-centre, outpatient, and single-dose study used 200 patients of both sexes and homogenous ethnicity after third molar surgery (mean age 24 years, range 19-30 years). Primary outcome was sum pain intensity over 6 h (SPI). Secondary outcomes were time to analgesic onset, duration of analgesia, time to rescue drug intake, number of patients taking rescue drug, sum pain intensity difference (SPID), maximum pain intensity difference, time to maximum pain intensity difference, number needed to treat, prevent remedication and harm values, adverse effects, and patient-reported outcome measure (PROM).

RESULTS

Analgesia following ibuprofen and paracetamol combination with or without codeine was comparable. Both were better than paracetamol combined with codeine. Secondary variables supported this finding. Post hoc analysis of SPI and SPID revealed a sex/drug interaction trend in the codeine-containing groups where females experienced less analgesia. PROM showed a significant sex/drug interaction in the paracetamol and codeine group, but not in the other codeine-containing group. Especially females reported known and mild side effects in the codeine-containing groups.

CONCLUSION

Codeine added to ibuprofen/paracetamol does not seem to add analgesia in a sex-mixed study population. Sex may be a confounding factor when testing weak opioid analgesics such as codeine. PROM seems to be more sensitive than traditional outcome measures.

TRIAL REGISTRATION

ClinicalTrials.gov June 2009 NCT00921700.

Effect of preemptive photobiomodulation associated with nimesulide on the postsurgical outcomes, oxidative stress, and quality of life after third molar surgery: a randomized, split-mouth, controlled clinical trial

OBJECTIVE

The aim of this study is to compare the effect of photobiomodulation with low-level laser therapy (LLLT) and nimesulide on inflammatory parameters, biomarkers of oxidative stress and inflammation, and quality of life after lower third molar (L3M) surgery.

MATERIAL AND METHODS

A randomized, two-factor, triple-blind, controlled, split-mouth clinical trial was performed with 40 volunteers who required bilateral L3M removal. Patients were allocated depending on the use or not of 100 mg nimesulide 1 hbefore surgery, as well as the use or not of LLLT in the preoperative period.

RESULTS

Pain peaks occurred after 6 h (nimesulide-placebo [N-P] group) and 8 h (nimesulide group). In the N-P group, LLLT resulted in significantly lower mean pain scores than the subgroup without LLLT after 4 h (p = 0.009) and 6 h (p = 0.048). As for edema, a shorter distance between the mandibular angle and the outer canthus of the eyes after 7 days (p = 0.037) and a smaller cumulative effect (p = 0.036) were observed in the N-P group associated with LLLT. A direct effect between LLLT (p = 0.047) and a reduction in the mean scores of overall dissatisfaction with quality of life was detected.

CONCLUSIONS

Preemptive use of nimesulide only delayed peak pain. LLLT reduced edema, trismus, and contributed to a better perception of quality of life. Nimesulide inhibits peroxidation by increasing GSH and stopping neutrophil migration. The benefit of the association of both strategies was not superior to the use of LLLT alone.

CLINICAL RELEVANCE

Translational study with impact on clinical-surgical protocols involving L3M surgery related to pharmacological and non-pharmacological methods.

Single-Dose Ibuprofen-Arginine as a Preventive for Pain, Edema, and Trismus After Impacted Lower Third Molar Surgery: A Randomized Split-Mouth Clinical Trial

Objective  We examined if the association of ibuprofen with arginine has a better anti-inflammatory effect on pain, edema, and trismus after surgery of the impacted mandibular third molar than ibuprofen alone.

Materials and Methods  The study included 21 patients, 18 to 30 years of age, each with an impacted, and bilateral and symmetric third molar (total n  = 21) that required transalveolar extraction. Patients were randomly assigned numbers from 1 to 21. Group A received ibuprofen-arginine as preoperative medication, while Group B received only ibuprofen. Both groups received the same postoperative medications: amoxicillin + acetaminophen. All patients were evaluated for pain at 6, 12, and 24 hours. They were evaluated for edema and trismus before surgery; immediately after surgery; and at 24, 48, and 72 hours postoperatively. Postoperative pain scores used the visual analog scale (BS-11). For facial edema and trismus, linear measurements used the method modified by Gabka and Matsumura.

Statistical Analysis  For the evaluation of data between Group A and Group B, we used the statistical software SPSS version 22. The Shapiro-Wilk, analysis of variance, the Bonferroni comparisons, and the Wilcoxon test were used. All tests were based on a significance level of 0.05.

Results  The study results reveal that the facial edema scores of Group A and Group B presented statistically significant differences ( p  < 0.05), while for postoperative trismus, there was no statistically significant difference ( p  > 0.05) between the scores of Group A and Group B.

Conclusion  As a conclusion, we can state that the use of ibuprofen-arginine allows for significantly better control of pain and edema, and shows a tendency toward better recovery from trismus, although without statistical significance. Based on this, we can assert that arginine improves the anti-inflammatory power of ibuprofen, thus generating better tissue healing after surgery of the impacted third molar.

Analgesic effect of oral ibuprofen 400, 600, and 800 mg; paracetamol 500 and 1000 mg; and paracetamol 1000 mg plus 60 mg codeine in acute postoperative pain: a single-dose, randomized, placebo-controlled, and double-blind study

PURPOSE

Effect size estimates of analgesic drugs can be misleading. Ibuprofen (400 mg, 600 mg, 800 mg), paracetamol (1000 mg, 500 mg), paracetamol 1000 mg/codeine 60 mg, and placebo were investigated to establish the multidimensional pharmacodynamic profiles of each drug on acute pain with calculated effect size estimates.

METHODS

A randomized, double-blind, single-dose, placebo-controlled, parallel-group, single-centre, outpatient, and single-dose study used 350 patients (mean age 25 year, range 18 to 30 years) of homogenous ethnicity after third molar surgery. Primary outcome was sum pain intensity over 6 h. Secondary outcomes were time to analgesic onset, duration of analgesia, time to rescue drug intake, number of patients taking rescue drug, sum pain intensity difference, maximum pain intensity difference, time to maximum pain intensity difference, number needed to treat values, adverse effects, overall drug assessment as patient-reported outcome measure (PROM), and the effect size estimates NNT and NNTp.

RESULTS

Ibuprofen doses above 400 mg do not significantly increase analgesic effect. Paracetamol has a very flat analgesic dose-response profile. Paracetamol 1000/codeine 60 mg gives similar analgesia as ibuprofen from 400 mg, but has a shorter time to analgesic onset. Active drugs show no significant difference in maximal analgesic effect. Other secondary outcomes support these findings. The frequencies of adverse effects were low, mild to moderate in all active groups. NNT and NTTp values did not coincide well with PROMs.

CONCLUSION

Ibuprofen doses above 400 mg for acute pain offer limited analgesic gain. Paracetamol 1000 mg/codeine 60 mg is comparable to ibuprofen doses from 400 mg. Calculated effect size estimates and PROM in our study seem not to relate well as clinical analgesic efficacy estimators.

TRIAL REGISTRATION

NCT00699114.

Comparison of preemptive ibuprofen, acetaminophen, and placebo administration in reducing peri- and postoperative pain in primary tooth extraction: A randomized clinical trial

Background

The management of pain resulting from anesthesia injection, tooth extraction and in the period after extraction is of great importance in pediatric dentistry.

Objective

The aim of this study was to compare the efficacy of the preemptive administration of ibuprofen or acetaminophen with placebo in reducing the pain during injection, extraction and postoperatively in children undergoing primary tooth extraction.

Material and methods

A randomized, placebo‐controlled, triple‐blinded clinical trial of cooperative children who needed primary molar extraction by local anesthesia. Sixty‐six children aged between 6 and 8 years were randomly assigned to one of three groups: (a) Acetaminophen syrup (320 mg/10 ml); (b) placebo solution; and (c) ibuprofen syrup (200 mg/10 ml). Each of the three solutions was given 30 min before administration of the local anesthetic agent. The Pain level was assessed using the Wong–Baker faces® pain rating scale after injection, extraction, and postoperatively. The Kruskal–Wallis and Mann–Whitney U test were used to evaluate the pain scores between groups at confidence level of 95%.

Results

The use of preemptive analgesics showed lower pain scores compared to placebo. Additionally, only ibuprofen significantly reduced pain scores compared to placebo at the points immediately after injection (p = 0.001), immediately after extraction (p = 0.0001) and 5 h after extraction (p = 0.002).

Conclusion

Preemptive usage of ibuprofen reduces injection pain and relieves both extraction and postoperative pain in children undergoing primary tooth extraction.

What this paper or case report adds

It adds the knowledge regarding pain relief of injection and extraction in children.

Preemptive analgesic medications have a beneficial effect on alleviating postoperative pain following tooth extraction in children.

Ibuprofen is an effective analgesic for postoperative pain relief in children undergoing primary tooth extraction.

Why this paper or case report is important to pediatric dentists

Pediatric dentists may consider preemptive ibuprofen in children before injection and extractions.

Identifies that Ibuprofen is an effective method of reducing postoperative pain.

Paracetamol (acetaminophen): A familiar drug with an unexplained mechanism of action

Paracetamol (acetaminophen) is undoubtedly one of the most widely used drugs worldwide. As an over-the-counter medication, paracetamol is the standard and first-line treatment for fever and acute pain and is believed to remain so for many years to come. Despite being in clinical use for over a century, the precise mechanism of action of this familiar drug remains a mystery. The oldest and most prevailing theory on the mechanism of analgesic and antipyretic actions of paracetamol relates to the inhibition of CNS cyclooxygenase (COX) enzyme activities, with conflicting views on the COX isoenzyme/variant targeted by paracetamol and on the nature of the molecular interactions with these enzymes. Paracetamol has been proposed to selectively inhibit COX-2 by working as a reducing agent, despite the fact that in vitro screens demonstrate low potency on the inhibition of COX-1 and COX-2. In vivo data from COX-1 transgenic mice suggest that paracetamol works through inhibition of a COX-1 variant enzyme to mediate its analgesic and particularly thermoregulatory actions (antipyresis and hypothermia). A separate line of research provides evidence on potentiation of the descending inhibitory serotonergic pathway to mediate the analgesic action of paracetamol, but with no evidence of binding to serotonergic molecules. AM404 as a metabolite for paracetamol has been proposed to activate the endocannabinoid and the transient receptor potential vanilloid-1 (TRPV1) systems. The current review gives an update and in some cases challenges the different theories on the pharmacology of paracetamol and raises questions on some of the inadequately explored actions of paracetamol. List of Abbreviations: AM404, N-(4-hydroxyphenyl)-arachidonamide; CB1R, Cannabinoid receptor-1; Cmax, Maximum concentration; CNS, Central nervous system; COX, Cyclooxygenase; CSF, Cerebrospinal fluid; ED50, 50% of maximal effective dose; FAAH, Fatty acid amidohydrolase; IC50, 50% of the maximal inhibitor concentration; LPS, Lipopolysaccharide; NSAIDs, Non-steroidal anti-inflammatory drugs; PGE2, Prostaglandin E2; TRPV1, Transient receptor potential vanilloid-1.

Comparison between isolated and associated with codeine acetaminophen in pain control of acute apical abscess: a randomized clinical trial

OBJECTIVES

The study aimed to compare the acetaminophen administration efficacy or its combination with codeine for pain control in acute apical abscesses cases.

MATERIALS AND METHODS

Thirty-nine patients who sought emergency treatment in the Faculty of Dentistry of the Federal University of Rio Grande do Sul were included, all of them with acute apical abscess diagnosis. These patients were divided into two groups: acetaminophen group-prescription of acetaminophen (1000 mg) and acetaminophen-codeine group-prescription of acetaminophen (1000 mg) + codeine (30 mg), both with oral intake every 6 h for 3 days. The pain scores were recorded by the patients on their own at 6, 12, 24, 48, and 72 h after finishing clinical assistance, by filling a pain evolution journal, containing a visual analogue scale (VAS). Student t test was conducted to investigate different mean ages between groups 1 and 2. A comparison of weight and means of initial pain scores between groups was carried out using the Mann-Whitney U test. Chi-square test was performed to compare gender, affected tooth, education, initial swelling, and frequency of adverse effect between test and control groups. Mann-Whitney U test was applied to compare groups in the same period. Friedman's test was used to compare results from the same group over time.

RESULTS

Both groups showed score reduction over time (P < 0.05). Paracetamol-codeine group showed significant pain score reduction at 48 h registers when compared to baseline and at 6 h scores (P < 0.05). Further, pain scores at 72 h were significantly lower, when compared to the baseline, at 6 h, and at 12 h scores (P < 0.05). Acetaminophen group showed significant pain score reduction observed at 72 h, when compared to the baseline and at 6 h scores (P < 0.05). There were no significant differences in pain score reduction over time between groups (P > 0.05). There was no difference between the groups regarding the frequency of adverse reactions (P > 0.05).

CONCLUSION

Both medications were effective for pain control in acute apical abscess cases. The findings might have inferred in pain control of acute apical abscess associated pain in patients who used an antibiotic drug. External validity of the findings for acute apical abscess cases with no need for an antibiotic prescription is uncertain.

CLINICAL RELEVANCE

This paper suggests acetaminophen 1000 mg can be used for pain control in the treatment of acute apical abscess associated with systemic manifestation.

Evaluation of photobiomodulation effects on pain, edema, paresthesia, and bone regeneration after surgically assisted rapid maxillary expansion: Study protocol for a randomized, controlled, and double blind clinical trial

BACKGROUND

Surgically assisted rapid maxillary expansion (SARME) generates an uncomfortable postoperative period accompanied by pain, edema, and paresthesia. There are few studies on the effect of photobiomodulation (PBM) after SARME and it was not possible to find studies on the efficacy of light emitted by diode (LED) after this type of intervention. The main objective of the study will be to evaluate the efficacy of PBM with LED in the control of pain, facial edema, paresthesia, and bone repair after SARME.

METHODS

A randomized, double-blind, placebo-controlled clinical trial involving 72 participants aged from 18 to 45 years, who search the Department of Buccomaxillofacial Surgery and Traumatology of Mandaqui Hospital Complex, will be conducted. Immediately after surgeries, the participant will be inserted into the placebo or LED group. In the LED group, the participants will receive PBM with an extraoral device (660 and 850 nm with 6 J per point) and an intraoral device (660 nm with 2 J per point) and in the control group the person in charge of the application will simulate the irradiation with the devices kept off. The applications will be in the immediate postoperative period, 1, 2, 7, 14, 30, 60, 90, and 120 days after the end of the surgeries, when the evaluations will also be performed. Facial measurements, extra and intraoral sensitivity, pain and bone repair will be evaluated. Secondarily, data regarding the occurrence of headache; otalgia; nausea; bruising; nasolacrimation; epistaxis; dysphagia; systemic and superficial temperature in the operated region; use of analgesics and anti-inflammatories; anxiety and impact of oral health on the participants' quality of life will be computed.

DISCUSSION

Since PBM has shown positive effects on postoperative complications of other types of oral surgery and also has a positive effect on bone repair after maxillary disjunction, surgically assisted or not, it seems clear the need to evaluate its performance regarding pain, edema, and paresthesia after these surgeries.

TRIAL REGISTRATION

This protocol was registered in Clinical Trials platform (https://clinicaltrials.gov/) with the number NCT03814525, first published and last updated on January 24, 2019.

Attitude and Awareness of Dentists Practicing in Southern India Toward Non-steroidal Anti-inflammatory Drugs

Background:

Pain management is an everyday challenge in dentistry. Analgesics are the group of drugs prescribed for effective pain management, of which nonsteroidal anti-inflammatory drugs (NSAIDs) are the most commonly prescribed drugs. Selection of NSAIDs must be judiciously made considering their pharmacological properties and adverse effects.

Aim:

This study aimed to analyze the attitude toward analgesic prescription among practicing dentists and the awareness to update their knowledge about them.

Materials and Methods:

The study was carried out among 100 dental practitioners, where a questionnaire consisting of 16 questions was formulated based on the awareness of indication and contraindication, actual practice, and required future trends for updating the knowledge. The questionnaire was distributed among the practitioners; the answered questionnaire was collected and tabulated. Statistical analysis included χ² test to evaluate the significance.

Results:

Of 100 dental practitioners, 63% prescribed drugs based on the diagnosis. Aceclofenac was found to be the effective drug in postoperative pain management, whereas paracetamol was considered to be the safest among NSAIDs in clinical conditions such as bleeding disorders, gastric irritation, chronic kidney disease, and during pregnancy. All practicing dentists showed their willingness to participate in awareness programs in updating their knowledge.

Conclusion:

This study showed that dental clinical practitioners are well aware of the drugs to be prescribed in different clinical conditions but pitfalls have been observed in areas of systemic complication, where continuous educational programs are needed to overcome the same.

Acetaminophen Relieves Inflammatory Pain through CB1 Cannabinoid Receptors in the Rostral Ventromedial Medulla

Acetaminophen (paracetamol) is a widely used analgesic and antipyretic drug with only incompletely understood mechanisms of action. Previous work, using models of acute nociceptive pain, indicated that analgesia by acetaminophen involves an indirect activation of CB₁ receptors by the acetaminophen metabolite and endocannabinoid reuptake inhibitor AM 404. However, the contribution of the cannabinoid system to antihyperalgesia against inflammatory pain, the main indication of acetaminophen, and the precise site of the relevant CB₁ receptors have remained elusive. Here, we analyzed acetaminophen analgesia in mice of either sex with inflammatory pain and found that acetaminophen exerted a dose-dependent antihyperalgesic action, which was mimicked by intrathecally injected AM 404. Both compounds lost their antihyperalgesic activity in CB₁^-/- mice, confirming the involvement of the cannabinoid system. Consistent with a mechanism downstream of proinflammatory prostaglandin formation, acetaminophen also reversed hyperalgesia induced by intrathecal prostaglandin E₂ To distinguish between a peripheral/spinal and a supraspinal action, we administered acetaminophen and AM 404 to hoxB8-CB₁^-/- mice, which lack CB₁ receptors from the peripheral nervous system and the spinal cord. These mice exhibited unchanged antihyperalgesia indicating a supraspinal site of action. Accordingly, local injection of the CB₁ receptor antagonist rimonabant into the rostral ventromedial medulla blocked acetaminophen-induced antihyperalgesia, while local rostral ventromedial medulla injection of AM 404 reduced hyperalgesia in wild-type mice but not in CB₁^-/- mice. Our results indicate that the cannabinoid system contributes not only to acetaminophen analgesia against acute pain but also against inflammatory pain, and suggest that the relevant CB₁ receptors reside in the rostral ventromedial medulla.SIGNIFICANCE STATEMENT Acetaminophen is a widely used analgesic drug with multiple but only incompletely understood mechanisms of action, including a facilitation of endogenous cannabinoid signaling via one of its metabolites. Our present data indicate that enhanced cannabinoid signaling is also responsible for the analgesic effects of acetaminophen against inflammatory pain. Local injections of the acetaminophen metabolite AM 404 and of cannabinoid receptor antagonists as well as data from tissue-specific CB₁ receptor-deficient mice suggest the rostral ventromedial medulla as an important site of the cannabinoid-mediated analgesia by acetaminophen.

Decreased post-operative pain using a sublingual injection of dexamethasone (8 mg) in lower third molar surgery

Background

Every patient who undergoes mandibular third molar surgery is concerned about post-operative pain. Indeed, previous researchers have used various methods to treat such pain. This study aimed to assess the effectiveness of sublingual injection of dexamethasone (8 mg) to treat post-operative pain after mandibular third molar surgery.

Method

This was a randomized, double-blind, split-mouth, clinical trial, involving 48 healthy patients who required surgical removal of two mandibular third molars with similar bilateral positions. All operations were performed by the same experienced surgeon. The patients were randomized into a study group (8 mg dexamethasone injection) and a placebo group (normal saline injection). Both interventions were injected into the sublingual space immediately after local anesthesia, 30 min before the first incision. The study group received an 8 mg dexamethasone injection, while the placebo group received a normal saline injection. The wash period between the patients' two operations was 3 to 4 weeks. Pain was assessed by recording the number of analgesic tablets (rescue drug) consumed, as well as by noting the patients' responses to the visual analog scale (VAS) on the first, second, and third days after surgery.

Results

The study group differed significantly from the placebo group in terms of VAS score and analgesic consumption.

Conclusion

Dexamethasone (8 mg), injected sublingually, significantly eased post-operative pain after surgical removal of the mandibular third molar.

Identifying adults at risk of paracetamol toxicity in the acute dental setting: development of a clinical algorithm

Paracetamol is widely used and effective for the management of dental pain in the UK. Acute dental pain is a recognised precipitant of unintentional paracetamol overdose and in a small but significant number of cases this results in hepatotoxicity. Patients' understanding of the risks of excess paracetamol ingestion remains poor and risk of over-medication before presentation is increased due to a variety of factors including dental anxiety and fragmented provision of dental emergency services. Early recognition of overdose is crucial to preventing significant hepatotoxicity and death. Dentists have a role to play in recognising unintentional overdose cases and directing patients timeously to appropriate medical care. Guidelines on the treatment of paracetamol toxicity are readily available but our data suggests some dental settings may present a weak link in the care pathway and overdose may not be readily recognised. We have developed an algorithm and training package targeted at dentists in the acute dental setting with the aim of improving recognition of paracetamol toxicity in adults and directing onward referral appropriately. This paper also revises the key pharmacokinetics and pharmacodynamics of paracetamol and is intended to raise awareness of issues of toxicity for dentists.

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.

Comparison of the efficacy of low doses of methylprednisolone, acetaminophen, and dexketoprofen trometamol on the swelling developed after the removal of impacted third molar

BACKGROUND

The aim of the present study was to compare the efficacy of low doses of methylprednisolone, acetaminophen and dexketoprofen trometamol, which are among the drug groups used in our clinic, on postoperative swelling developing after removal of impacted third molar.

MATERIAL AND METHODS

The three group of patients received either 40 mg methylprednisolone or 300 mg acetaminophen or 12.5 mg dexketoprofen trometamol one hour before the procedure, according to the patient groups. The patients in the methylprednisolone group were injected with methylprednisolone at a dose of 20 mg 24 hour after the procedure and prescribed 300 mg acetaminophen as rescue analgesic. During the postoperative period, the doses that were given before the procedure were continued 3 times a day for 2 days in the acetaminophen and dexketoprofen trometamol groups. Maximal swelling was assessed preoperatively and at the postoperative 48 hours by ultrasound images.

RESULTS

Swelling was 34% lower in the methylprednisolone than in the other groups; however, no statistically significant difference was found between the groups. The acetaminophen and dexketoprofen trometamol groups exhibited clinical results close to each other.

CONCLUSIONS

Combination of low doses of methylprednisolone and acetaminophen provide a safe and adequate clinical success on swelling.

Prospective double-blind clinical trial evaluating the effectiveness of Bromelain in the third molar extraction postoperative period

OBJECTIVES

To evaluate the anti-inflammatory and analgesic effect of Bromelain (pineapple extract) administered orally in the postoperative after extraction of impacted lower molars.

STUDY DESIGN

This is a prospective, placebo-controlled, unicentric, double-blind study; the sample size was 34 patients. The pre and postoperative outcomes, evaluated on the third (D3) and eighth day (D8), included inflamtion, pain and oral aperture, as well as the need for analgesics. One group received Bromelain 150mg per day for three days and 100mg on days 4 to 7. The other group received placebo in the same dosage. All outcomes werrecorded quantitatively and analyzed with the Mann-Whitney U test for independent samples.

RESULTS

Although there were no statistically significant differences between the treatment groups, a trend towards less inflammation and improved oral aperture was observed in the group that received Bromelain, compared to the group that received placebo. This trend can be attributed completely to random reasons, since there is no statistical difference in the results.

CONCLUSIONS

Further studies are necessary to analyze different administration patterns and doses of Bromelain for the use in the postoperative of impacted third molars.

Effect of low-level laser therapy on the post-surgical inflammatory process after third molar removal: study protocol for a double-blind randomized controlled trial

Background

Low-level laser therapy (LLLT) has been shown to modulate the inflammatory process without adverse effects , by reducing pain and swelling and promoting the repair of damaged tissues. Because pain, swelling and muscle spasm are complications found in virtually all patients following oral surgery for the removal of impacted teeth, this model has been widely used to evaluate the effects of LLLT on the inflammatory process involving bone and, connective tissue and the muscles involved in mastication.

Methods/Design

After meeting the eligibility criteria, 60 patients treated at a Specialty Dental Center for the removal of impacted lower third molars will be randomly divided into five groups according to the type of laser therapy used at the end of surgery (intraoral irradiation with 660 nm laser; extraoral irradiation with 660 nm laser; intraoral irradiation with 808 nm laser; extraoral irradiation with 808 nm laser and no irradiation). To ensure that patients are blinded to the type of treatment they are receiving, the hand piece of the laser apparatus will be applied both intraorally and extraorally to all participants, but the device will be turned on only at the appropriate time, as determined by the randomization process. At 2 and 7 days after surgery, the patients will be evaluated by three blinded evaluators who will measure of swelling, mouth opening (muscle spasm evaluation) and pain (using two different pain scales). The 14-item Oral Health Impact Profile (OHIP-14) will be used to assess QOL. All data will be analyzed with respect to the normality of distribution using the Shapiro-Wilk test. Statistically significant differences between the experimental groups will be determined using analysis of variance, followed by a suitable post hoc test, when necessary. The significance level will be set at α = 0.05.

Discussion

The lack of standardization in studies with regard to the samples, methods and LLLT parameters complicates the determination of the actual effect of laser therapy on this model. The present study aims to provide a randomized, controlled, double-blind trial to compare four different LLLT parameters in relation to the outcomes of pain, swelling and muscle spasm following surgery for the extraction of impacted third molars and evaluate the effects os surgery on patients' quality os life (QOL).

Trial registration

Brazilian Registry of Clinical Trials - Rebec (RBR-6XSB5H).

The modern pharmacology of paracetamol: therapeutic actions, mechanism of action, metabolism, toxicity and recent pharmacological findings

Paracetamol is used worldwide for its analgesic and antipyretic actions. It has a spectrum of action similar to that of NSAIDs and resembles particularly the COX-2 selective inhibitors. Paracetamol is, on average, a weaker analgesic than NSAIDs or COX-2 selective inhibitors but is often preferred because of its better tolerance. Despite the similarities to NSAIDs, the mode of action of paracetamol has been uncertain, but it is now generally accepted that it inhibits COX-1 and COX-2 through metabolism by the peroxidase function of these isoenzymes. This results in inhibition of phenoxyl radical formation from a critical tyrosine residue essential for the cyclooxygenase activity of COX-1 and COX-2 and prostaglandin (PG) synthesis. Paracetamol shows selectivity for inhibition of the synthesis of PGs and related factors when low levels of arachidonic acid and peroxides are available but conversely, it has little activity at substantial levels of arachidonic acid and peroxides. The result is that paracetamol does not suppress the severe inflammation of rheumatoid arthritis and acute gout but does inhibit the lesser inflammation resulting from extraction of teeth and is also active in a variety of inflammatory tests in experimental animals. Paracetamol often appears to have COX-2 selectivity. The apparent COX-2 selectivity of action of paracetamol is shown by its poor anti-platelet activity and good gastrointestinal tolerance. Unlike both non-selective NSAIDs and selective COX-2 inhibitors, paracetamol inhibits other peroxidase enzymes including myeloperoxidase. Inhibition of myeloperoxidase involves paracetamol oxidation and concomitant decreased formation of halogenating oxidants (e.g. hypochlorous acid, hypobromous acid) that may be associated with multiple inflammatory pathologies including atherosclerosis and rheumatic diseases. Paracetamol may, therefore, slow the development of these diseases. Paracetamol, NSAIDs and selective COX-2 inhibitors all have central and peripheral effects. As is the case with the NSAIDs, including the selective COX-2 inhibitors, the analgesic effects of paracetamol are reduced by inhibitors of many endogenous neurotransmitter systems including serotonergic, opioid and cannabinoid systems. There is considerable debate about the hepatotoxicity of therapeutic doses of paracetamol. Much of the toxicity may result from overuse of combinations of paracetamol with opioids which are widely used, particularly in USA.

Paracetamol and cyclooxygenase inhibition: is there a cause for concern?

Paracetamol is recommended as first-line therapy for pain associated with osteoarthrosis and is one of the most widely used over-the-counter analgesic drugs worldwide. Despite its extensive use, its mode of action is still unclear. Although it is commonly stated that paracetamol acts centrally, recent data imply an inhibitory effect on the activity of peripheral prostaglandin-synthesising cyclooxygenase enzymes. In this context paracetamol has been suggested to inhibit both isoforms in tissues with low levels of peroxide by reducing the higher oxidation state of cyclooxygenase enzymes. Two recent studies have also demonstrated a preferential cyclooxygenase 2 (COX-2) inhibition by paracetamol under different clinically relevant conditions. This review attempts to relate data on paracetamol's inhibitory action on peripheral cyclooxygenase enzymes to the published literature on its anti-inflammatory action and its hitherto underestimated side-effects elicited by cyclooxygenase inhibition. As a result, a pronounced COX-2 inhibition by paracetamol is expected to occur in the endothelium, possibly explaining its cardiovascular risk in epidemiological studies. A careful analysis of paracetamol's cardiovascular side-effects in randomised studies is therefore strongly advised. On the basis of epidemiological data showing an increased gastrointestinal risk of paracetamol at high doses or when co-administered with classic cyclooxygenase inhibitors, paracetamol's long-term gastrointestinal impact should be investigated in randomised trials. Finally, paracetamol's fast elimination and consequently short-lived COX-2 inhibition, which requires repetitive dosing, should be definitely considered to avoid overdosage leading to hepatotoxicity.

Comparison of pre-emptive ibuprofen, paracetamol, and placebo administration in reducing post-operative pain in primary tooth extraction

BACKGROUND

This study investigates preliminary investigations that a pre-emptive analgesia administration may reduce post-extraction pain.

AIM

This prospective, placebo-controlled, randomized, double-blind trial was planned to compare the efficacy of the pre-emptive administration of ibuprofen, paracetamol, and placebo in reducing post-extraction pain in children.

DESIGN

Forty-five children, ages 6-12, who needed primary mandibular molar tooth extraction were treated in paediatric dental clinics, with treatment preceded by local anaesthesia and analgesic drugs during the preoperative period. A five-face scale was used to evaluate pain reaction during the injection, extraction, and post-operative period. Self-report scores were recorded when the local anaesthesia had been administered in soft tissues and both before and after the extraction was completed. The Kruskal-Wallis and Mann-Whitney U tests (with Bonferroni correction paired t-test as the post hoc test) were used at a confidence level of 95%.

RESULTS

The use of pre-emptive analgesics showed lower scores compared to the placebo, irrespective of the age, weight, gender of the child, and the number of teeth extracted during the study period. Additionally, ibuprofen exhibited lower pain scores (P < 0.05) compared to paracetamol at the 15-min (P < 0.001) and 4-h (P < 0.009) periods.

CONCLUSIONS

Preoperative use of ibuprofen and paracetamol may provide a pre-emptive analgesic effect in paediatric patients who receive adequate analgesia during mandibular primary tooth extraction.

Prevention of pain on injection of propofol: a comparison of lidocaine with different doses of paracetamol

BACKGROUND AND OBJECTIVE

The aim of this study was to compare the efficacy of pretreatment with paracetamol 0.5 mg kg(-1), 1 mg kg(-1), 2 mg kg(-1) and lidocaine 0.5 mg kg(-1) for prevention of propofol induced pain.

METHODS

In this double-blind, placebo-controlled study, 250 adult patients ASA I or II, scheduled to undergo elective surgery, were randomly assigned into five groups of 50 each. Group P0.5, group P1 and group P2 received 0.5, 1 and 2 mg kg(-1) paracetamol respectively; group L received 0.5 mg kg(-1) lidocaine; and the control group, group C, received isotonic saline pretreatment in the dorsum of the hand, followed by propofol 1 min later. A blinded researcher assessed the patient's pain level via a four-point scale.

RESULTS

There were no significant differences in patient characteristics among the groups. The incidence of propofol injection pain in all treatment groups was significantly lower than in the control group (P < 0.001). When the paracetamol 0.5 mg kg(-1) group was compared with both the paracetamol 1 mg kg(-1) group (P < 0.01) and the paracetamol 2 mg kg(-1) group (P < 0.001), significant differences were observed. In the lidocaine 0.5 mg kg(-1) group propofol injection pain was significantly reduced compared with the paracetamol 0.5 mg kg(-1) group (P < 0.01). However, in the paracetamol 2 mg kg(-1) group pain was more significantly reduced than in the lidocaine 0.5 mg kg(-1) group (P < 0.001). In the paracetamol 2 mg kg(-1) group the incidence of pain was significantly less than in paracetamol 1 mg kg(-1) group (P < 0.001).

CONCLUSION

When given as venous retention pretreatments 1 min before propofol, paracetamol 1 mg kg(-1) and lidocaine 0.5 mg kg(-1) were equally effective in attenuating pain during intravenous (i.v.) injection of propofol whereas pretreatment with paracetamol 2 mg kg(-1) was shown to be the most effective treatment.

Efficacy and Safety of Ibuprofen and Acetaminophen in Children and Adults: A Meta-Analysis and Qualitative Review

Objective:

To evaluate the analgesic and antipyretic efficacy and safety of ibuprofen compared to acetaminophen in children and adults.

Data Sources:

Literature searches were performed using PubMed/MEDLINE (through August 2009) and EMBASE (through January 2008) and were restricted to the English language. In PubMed/MEDLINE, search terms used were ibuprofen, acetaminophen, paracetamol, clinical trials, and randomized controlled trials. EMBASE search terms included ibuprofen and acetaminophen, restricted to human and clinical trials.

Study Selection And Data Extraction:

All English-language articles identified from the data sources were reviewed. Multiple review articles were studied for any pertinent references and this yielded additional articles. Only articles that directly compared ibuprofen and acetaminophen were eligible for this review.

Data Synthesis:

Eighty-five studies that directly compared ibuprofen to acetaminophen were identified; 54 contained analgesic efficacy data, 35 contained antipyretic/temperature reduction data, and 66 contained safety data (some articles contained more than 1 type of data). Qualitative review of the literature revealed that, for the most part, ibuprofen was more efficacious than acetaminophen for the treatment of pain and fever in both pediatric and adult populations, and that these 2 drugs were equally safe. Meta-analyses on the subset of randomized clinical trial articles that reported sufficient quantitative information to calculate either an odds ratio (adverse event [AE]) or standardized mean difference (pain and fever) confirmed the qualitative results for adult (standardized mean difference [SMD] 0.69; 95% CI 0.57 to 0.81) and pediatric (SMD 0.28; 95% CI 0.10 to 0.46) pain at 2 hours postdose and pediatric fever (SMD 0.26; 95% CI 0.10 to 0.41) at 4 hours postdose. Conclusions regarding adult fever/temperature reduction could not be made due to a lack of evaluable data. The combined odds ratio for the proportion of adult subjects experiencing at least 1 AE slightly favored ibuprofen; however, the difference was not statistically significant (1.12; 95% CI 1.00 to 1.25). No significant difference between drugs in AE incidence was found for pediatric patients (0.82; 95% CI 0.60 to 1.12).

Conclusions:

Ibuprofen is as or more efficacious than acetaminophen for the treatment of pain and fever in adult and pediatric populations and is equally safe.

Pain management in patients with chronic kidney disease

Pain has been reported to be a common problem in the general population and end-stage renal disease (ESRD) patients. Although similar data for pre-ESRD patients are lacking, we recently reported that the prevalence of pain is also very high (>70%) among pre-ESRD patients at a Los Angeles County tertiary referral centre. The high prevalence of pain in the CKD population is particularly concerning because pain has been shown to be associated with poor quality of life. Of greater concern, poor quality of life, at least in dialysis patients, has been shown to be associated with poor survival. We herein discuss the pathophysiology of common pain conditions, review a commonly accepted approach to the management of pain in the general population, and discuss analgesic-induced renal complications and therapeutic issues specific for patients with reduced renal function.

Peri-operative use of paracetamol

This article is a review of the peri-operative use of paracetamol. It reviews the pharmacology of paracetamol, highlighting new information about the mechanism of action, and examines its therapeutic use in the peri-operative period, focusing on efficacy, route of administration, and the use of a loading dose to improve early postoperative analgesia.

Single dose oral paracetamol (acetaminophen) for postoperative pain in adults

BACKGROUND

This is an updated version of the original Cochrane review published in Issue 1, 2004 - this original review had been split from a previous title on 'Single dose paracetamol (acetaminophen) with and without codeine for postoperative pain'. The last version of this review concluded that paracetamol is an effective analgesic for postoperative pain, but additional trials have since been published. This review sought to evaluate the efficacy and safety of paracetamol using current data, and to compare the findings with other analgesics evaluated in the same way.

OBJECTIVES

To assess the efficacy of single dose oral paracetamol for the treatment of acute postoperative pain.

SEARCH STRATEGY

We searched The Cochrane Library, MEDLINE, EMBASE, the Oxford Pain Relief Database and reference lists of articles to update an existing version of the review in July 2008.

SELECTION CRITERIA

Randomised, double-blind, placebo-controlled clinical trials of paracetamol for acute postoperative pain in adults.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. Area under the "pain relief versus time" curve was used to derive the proportion of participants with paracetamol or placebo experiencing at least 50% pain relief over four to six hours, using validated equations. Number-needed-to-treat-to-benefit (NNT) was calculated, with 95% confidence intervals (CI). The proportion of participants using rescue analgesia over a specified time period, and time to use, were sought as measures of duration of analgesia. Information on adverse events and withdrawals was also collected.

MAIN RESULTS

Fifty-one studies, with 5762 participants, were included: 3277 participants were treated with a single oral dose of paracetamol and 2425 with placebo. About half of participants treated with paracetamol at standard doses achieved at least 50% pain relief over four to six hours, compared with about 20% treated with placebo. NNTs for at least 50% pain relief over four to six hours following a single dose of paracetamol were as follows: 500 mg NNT 3.5 (2.7 to 4.8); 600 to 650 mg NNT 4.6 (3.9 to 5.5); 975 to 1000 mg NNT 3.6 (3.4 to 4.0). There was no dose response. Sensitivity analysis showed no significant effect of trial size or quality on this outcome.About half of participants needed additional analgesia over four to six hours, compared with about 70% with placebo. Five people would need to be treated with 1000 mg paracetamol, the most commonly used dose, to prevent one needing rescue medication over four to six hours, who would have needed it with placebo. Adverse event reporting was inconsistent and often incomplete. Reported adverse events were mainly mild and transient, and occurred at similar rates with 1000 mg paracetamol and placebo. No serious adverse events were reported. Withdrawals due to adverse events were uncommon and occurred in both paracetamol and placebo treatment arms.

AUTHORS' CONCLUSIONS

A single dose of paracetamol provides effective analgesia for about half of patients with acute postoperative pain, for a period of about four hours, and is associated with few, mainly mild, adverse events.

Acetaminophen (paracetamol) is a selective cyclooxygenase-2 inhibitor in man

For more than three decades, acetaminophen (INN, paracetamol) has been claimed to be devoid of significant inhibition of peripheral prostanoids. Meanwhile, attempts to explain its action by inhibition of a central cyclooxygenase (COX)-3 have been rejected. The fact that acetaminophen acts functionally as a selective COX-2 inhibitor led us to investigate the hypothesis of whether it works via preferential COX-2 blockade. Ex vivo COX inhibition and pharmacokinetics of acetaminophen were assessed in 5 volunteers receiving single 1000 mg doses orally. Coagulation-induced thromboxane B(2) and lipopolysaccharide-induced prostaglandin E(2) were measured ex vivo and in vitro in human whole blood as indices of COX-1 and COX-2 activity. In vitro, acetaminophen elicited a 4.4-fold selectivity toward COX-2 inhibition (IC(50)=113.7 micromol/L for COX-1; IC(50)=25.8 micromol/L for COX-2). Following oral administration of the drug, maximal ex vivo inhibitions were 56% (COX-1) and 83% (COX-2). Acetaminophen plasma concentrations remained above the in vitro IC(50) for COX-2 for at least 5 h postadministration. Ex vivo IC(50) values (COX-1: 105.2 micromol/L; COX-2: 26.3 micromol/L) of acetaminophen compared favorably with its in vitro IC(50) values. In contrast to previous concepts, acetaminophen inhibited COX-2 by more than 80%, i.e., to a degree comparable to nonsteroidal antiinflammatory drugs (NSAIDs) and selective COX-2 inhibitors. However, a >95% COX-1 blockade relevant for suppression of platelet function was not achieved. Our data may explain acetaminophen's analgesic and antiinflammatory action as well as its superior overall gastrointestinal safety profile compared with NSAIDs. In view of its substantial COX-2 inhibition, recently defined cardiovascular warnings for use of COX-2 inhibitors should also be considered for acetaminophen.

Effect estimates and methodological quality of randomized controlled trials about prevention of alveolar osteitis following tooth extraction: a systematic review

OBJECTIVE

To systematically review the scientific evidence derived from randomized controlled trials (RCT) about prevention of alveolar osteitis (AO).

STUDY DESIGN

Literature searches were conducted to locate RCTs about prevention of AO. The RCTs were scrutinized for methodological details and categorized according to the preventive intervention studied. Data were analyzed in relation to the frequency of AO. Absolute risk reductions (ARR), and numbers needed to treat were calculated with 95% confidence limits.

RESULTS

There was a wide variation in the design and quality of the RCTs (N = 32). The greatest risk reduction for AO was seen for local treatment with tetracycline (ARR, 12%-31%). For a majority of the preventive interventions, the evidence was absent or inconclusive.

CONCLUSIONS

Local treatment with tetracycline, and also 0.12% chlorhexidine rinsing preoperatively and 7 days postoperatively, seem to have significant and clinically relevant preventive effect on AO following surgical removal of lower third molars.

Randomized controlled noninferiority trial to compare extended release acetaminophen and ibuprofen for the treatment of ankle sprains

STUDY OBJECTIVE

To compare acetaminophen extended release 1,300 mg 3 times daily and ibuprofen 400 mg 3 times daily for treatment of signs and symptoms of grade I or II lateral ankle sprains.

METHODS

Patients (N=260) 18 years or older and with grade I or II lateral ankle sprains were randomized to receive acetaminophen extended release 1,300 mg 3 times daily or ibuprofen 400 mg 3 times daily for 9 days. Primary endpoint was change from baseline at day 4 in pain on walking. Other endpoints included change from baseline at day 9 in pain on walking; change from baseline at days 4 and 9 in ability to walk and ankle swelling, bruising, and range of motion; satisfaction with treatment on days 4 and 9; percentage of patients with positive anterior drawer test on day 4; and time to resume normal activity. Safety assessments consisted of reported adverse events. This study had a noninferiority design in which the hypothesis was that acetaminophen extended release was not inferior to ibuprofen for treatment of signs and symptoms of grade I or II lateral ankle sprains.

RESULTS

The difference in least squares means (acetaminophen extended release, ibuprofen) with respect to the primary endpoint within the per-protocol population was -0.88; acetaminophen extended release was comparable to ibuprofen for the primary endpoint because the upper limit (3.26) of the 1-sided 95% confidence interval (CI) for the difference in least squares means did not exceed the noninferiority limit of 6.90. The intention-to-treat population was used to test the second step of the 2-step testing process because the null hypothesis was rejected in the noninferiority test. For this analysis, the difference between acetaminophen extended release and ibuprofen in the least squares mean change from baseline for the primary endpoint was -1.63 (not significant). Results showed that acetaminophen extended release was noninferior to ibuprofen with respect to the secondary endpoints. No serious drug-related adverse events were reported. The most common adverse events, reported by 6.5% of patients, were in the gastrointestinal system (mainly nausea and upper abdominal pain).

CONCLUSION

Acetaminophen extended release 3,900 mg daily was comparable to ibuprofen 1,200 mg daily for treatment of grade I or II lateral ankle sprains. Both treatments were well tolerated.

Acetaminophen, like conventional NSAIDs, may reduce synovitis in osteoarthritic knees

OBJECTIVE

To determine the extent to which treatment of patients with symptomatic knee osteoarthritis (OA) with non-steroidal anti-inflammatory drugs (NSAIDs) and acetaminophen (ACET) reduces total effusion volume and synovial tissue volume, as quantified by magnetic resonance imaging (MRI).

METHODS

Sequential pilot studies used subjects whose knee OA was treated with NSAIDs (n=10) or with ACET <or=4 g/day (n=20), respectively. After a five half-lives washout of their pain medication, the OA knee with the higher pain score >or=15 of 25 on the Western Ontario and McMaster Universities' pain scale underwent l.5T MRI. Effusion was quantified in axial short tau inversion recovery images; to measure synovial tissue volume, fat-suppressed T1-weighted axial images were obtained 3 min after i.v. injection of gadolinium contrast. After the initial MRI examination, patients resumed their customary pain medications until the severity of knee pain returned to baseline, when pain was again measured and the MRI was repeated.

RESULTS

Pain severity after washout was similar in subjects taking ACET and NSAIDs. Reinstitution of ACET resulted in a 50% decrease in the mean of pain scores (P=1.7 x 10(-12)) that was comparable with that seen after the reinstitution of NSAID (49%, P=6.0 x 10(-7)). The mean total effusion volume measured during the flare of knee pain induced by the withdrawal of the two drugs was comparable (ACET 16.9 ml, NSAID 16.2 ml; P=0.884). Significant decreases in mean total effusion volume were observed after reinstitution of both ACET (-4.5 ml, P=0.009) and NSAID (-3.3 ml, P=0.013); the difference between drugs was not significant. Analyses of synovial volume yielded similar results.

CONCLUSION

While uncontrolled and derived from small samples, these data suggest that ACET may have a significant anti-inflammatory effect in patients with knee OA, comparable with that achieved with NSAIDs, possibly through an effect on neurogenic inflammation. Joint pain is the clinical feature of OA that most often leads the affected individual to seek medical attention. Because many patients with OA improve symptomatically with the use of NSAIDs, it has been widely assumed that the pain of OA is due to synovial inflammation. However, the origins of OA pain are numerous and may vary from patient to patient and, within the same subject, from visit to visit. Although the articular cartilage is usually the site of the most obvious pathological changes in this disease, it is aneural and, therefore, is not the source of joint pain. However, in addition to the synovium, the subchondral bone, joint capsule, osteophytes, menisci, ligaments, periarticular tendons, entheses and bursae all contain nociceptive nerve endings, stimulation of which by chemical or physical mediators may be a basis for OA pain.

Drugs for pain management in dentistry

Pain is one of the most common reasons patients seek dental treatment. It may be due to many different diseases/conditions or it may occur after treatment. Dentists must be able to diagnose the source of pain and have strategies for its management. The '3-D's' principle--diagnosis, dental treatment and drugs--should be used to manage pain. The first, and most important, step is to diagnose the condition causing the pain and identify what caused that condition. Appropriate dental treatment should then be undertaken to remove the cause of the condition as this usually provides rapid resolution of the symptoms. Drugs should only be used as an adjunct to the dental treatment. Most painful problems that require analgesics will be due to inflammation. Pain management drugs include non-narcotic analgesics (e.g., non-steroidal anti-inflammatory drugs, paracetamol, etc) or opioids (i.e., narcotics). Non-steroidal anti-inflammatory drugs (NSAIDs) provide excellent pain relief due to their anti-inflammatory and analgesic action. The most common NSAIDs are aspirin and ibuprofen. Paracetamol gives very effective analgesia but has little anti-inflammatory action. The opioids are powerful analgesics but have significant side effects and therefore they should be reserved for severe pain only. The most commonly-used opioid is codeine, usually in combination with paracetamol. Corticosteroids can also be used for managing inflammation but their use in dentistry is limited to a few very specific situations.

Effects of Ibuprofen and High-Voltage Electric Stimulation on Acute Edema Formation After Blunt Trauma to Limbs of Rats

Context: Ibuprofen is widely used to manage pain and inflammation after orthopaedic trauma, but its effect on acute swelling has not been investigated. Cathodal high-voltage pulsed current (CHVPC) at 120 pulses per second and 90% of visible motor threshold is known to curb edema formation after blunt trauma to the hind limbs of rats.Objective: To examine the effects of ibuprofen, continuous CHVPC, and simultaneous ibuprofen and CHVPC on acute edema formation after blunt trauma to the hind limbs of rats.Design: Randomized, parallel-group, repeated-measures design.Setting: Laboratory animal facility.Participants: A total of 21 3-month-old Zucker Lean rats (mass = 288 +/- 55 g) were studied.Intervention(s): We assessed the effects of ibuprofen, continuous CHVPC, and simultaneous ibuprofen and CHVPC on acute edema formation after blunt trauma to the hind limbs of rats.Main Outcome Measure(s): Limb volumes were measured immediately before and after trauma and every 30 minutes over the 4 hours of the experiment.Results: Volumes of treated limbs of all 3 experimental groups were smaller (P < .05) than those of untreated limbs, but no treatment was more effective than another.Conclusions: Ibuprofen, CHVPC, and simultaneous ibuprofen and CHVPC effectively curbed edema after blunt injury by roughly 50% relative to untreated but similarly injured control limbs of rats.

Mechanism of action of paracetamol

Paracetamol (acetaminophen) is generally considered to be a weak inhibitor of the synthesis of prostaglandins (PGs). However, the in vivo effects of paracetamol are similar to those of the selective cyclooxygenase-2 (COX-2) inhibitors. Paracetamol also decreases PG concentrations in vivo, but, unlike the selective COX-2 inhibitors, paracetamol does not suppress the inflammation of rheumatoid arthritis. It does, however, decrease swelling after oral surgery in humans and suppresses inflammation in rats and mice. Paracetamol is a weak inhibitor of PG synthesis of COX-1 and COX-2 in broken cell systems, but, by contrast, therapeutic concentrations of paracetamol inhibit PG synthesis in intact cells in vitro when the levels of the substrate arachidonic acid are low (less than about 5 mumol/L). When the levels of arachidonic acid are low, PGs are synthesized largely by COX-2 in cells that contain both COX-1 and COX-2. Thus, the apparent selectivity of paracetamol may be due to inhibition of COX-2-dependent pathways that are proceeding at low rates. This hypothesis is consistent with the similar pharmacological effects of paracetamol and the selective COX-2 inhibitors. COX-3, a splice variant of COX-1, has been suggested to be the site of action of paracetamol, but genomic and kinetic analysis indicates that this selective interaction is unlikely to be clinically relevant. There is considerable evidence that the analgesic effect of paracetamol is central and is due to activation of descending serotonergic pathways, but its primary site of action may still be inhibition of PG synthesis. The action of paracetamol at a molecular level is unclear but could be related to the production of reactive metabolites by the peroxidase function of COX-2, which could deplete glutathione, a cofactor of enzymes such as PGE synthase.

Colon perforation with acute peritonitis after taking clindamycin and diclofenac following wisdom tooth removal

INTRODUCTION

Non-steroidal anti-inflammatory drugs have a high analgesic and anti-inflammatory effect and are widely taken for acute and chronic pain. Especially following long-term use, they may cause gastrointestinal side effects such as mucosal ulceration, perforation and strictures in the small and large bowel.

PATIENT

A 16-year-old female developed colonic perforation and purulent peritonitis after wisdom tooth removal and short-term intake of non-steroidal anti-inflammatory drugs.

DISCUSSION

Non-steroidal anti-inflammatory drugs may exert their deleterious effects on the lower gastrointestinal tract through both local and systemic actions. Systemic effects are caused by the inhibition of cyclooxygenase and reduction of protective prostaglandins. The local damage of the intestinal mucosa in the distal bowel segments seems to be caused by sustained release formulation with a high enterohepatic circulation. The latter may act time and again on the intestinal mucosa through metabolites secreted in the gallbladder. Concomitant intake of clindamycin may have favoured this acute complication.

CONCLUSION

Intestinal perforation after short-term intake of non-steroidal anti-inflammatory drugs is very rare. However, it is life-threatening and illustrates the need for careful prescribing at as low an effective dose and as short a time as possible, especially when combining different drugs. Paracetamol only has a weak effect on cyclooxygenase and continues to be a possible alternative for postoperative dental pain with a favourable benefit-risk ratio. It is the drug of choice for children, adolescents and patients with an increased risk of non-steroidal anti-inflammatory drug-induced gastro-enteropathy.