Dissociation between the antinociceptive and anti-inflammatory effects of the nonsteroidal anti-inflammatory drugs. A survey of their analgesic efficacy

Ketoprofen lysine salt treatment in adolescents with acute upper respiratory infections: a primary-care experience

BACKGROUND

Acute upper respiratory infections (AURI) are widespread in adolescents. Infections are associated with inflammation which in turn is responsible for symptoms and fever occurrence. Ketoprofen lysine salt (KLS) has a potent anti-inflammatory activity associated with effective analgesic and antipyretic effects and has a valuable safety profile. In this regard, KLS could be advantageous in adolescents with AURI.

METHODS

A group of primary-care pediatricians retrospectively collected data from adolescents with AURI treated with KLS for three days. Fever and symptom perception were assessed by a visual analog scale and were monitored daily for five days. Adolescents (or parents) sent their data to doctors using a phone application (WhatsApp; Meta Platforms, Inc., Menlo Park, CA, USA).

RESULTS

This retrospective analysis included sixty-one adolescents (mean age 13.4 years, females and males). KLS treatment markedly and quickly reduced fever and symptoms severity. In addition, the treatment was very well tolerated by all adolescents.

CONCLUSIONS

Adolescents present peculiar psychological characteristics that may determine some difficulties in prompt management of AURI treatment, while an adolescent with a respiratory infection requires a prompt and adequate cure. KLS, thanks to its pharmacologic profile, could be favorably used in this context. In addition, the treatment was safe, and the acceptability was high.

Clinical use of ketoprofen lysine salt: a reappraisal in adolescents with acute respiratory infections

Upper respiratory infections are widespread, and they are mainly of viral etiology. It has to be remarked that every infection is always associated with an inflammatory response. Inflammation implicates a cascade of bothersome symptoms, including fever, pain (headache, myalgia, and arthralgia), malaise, and respiratory complaints. As a result, anti-inflammatory medications could be beneficial as they act on different pathogenetic pathways. The ketoprofen lysine salt (KLS) has a potent anti-inflammatory activity associated with effective analgesic and antipyretic effects and has a valuable safety profile. However, adolescents present peculiar psychological characteristics that determine their difficulty to be managed. In this regard, an adolescent with a respiratory infection requires a prompt and adequate cure. KLS, thanks to its pharmacologic profile, could be favorably used in this regard. A recent primary-care experience outlined its effectiveness in this issue.

Comparing preemptive injection of peri-articular-multimodal drug with oral celexocib for postoperative pain management in total knee arthroplasty: A randomized clinical trial

Background

Total knee arthroplasty (TKA) is associated with tremendous postoperative pain, and pain relief should concisely be considered. This study aims to compare the efficacy of preemptive periarticular multimodal drug injection versus placebo and oral celecoxib on postoperative pain control after TKA.

Materials and Methods

This study is a randomized clinical trial on 146 patients candidate for TKA who were randomly allocated to three treatment groups, including (1) a cocktail consisting of bupivacaine, morphine, epinephrine, and ketorolac (n = 48), (2) only epinephrine (placebo group) (n = 49), and (3) 400 mg celecoxib orally (control group) (n = 49) using the Random Allocation software. The injections and oral therapy were performed within 15 min before the surgical procedure. The study's primary outcome was the Knee Society Score (KSS) calculated at baseline, within 6 weeks and 6 months postoperatively. Range of motion (ROM) and Visual Analog Scale (VAS) to assess pain intensity as the other primary outcomes were evaluated before the procedure, within 24 h, 48 h, and 6 weeks postoperatively.

Results

The three studied groups were similar regarding demographic characteristics, including age (P = 0.33), gender distribution (P = 0.65), and involved knee side (P = 0.94). Baseline comparison of KSS (P = 0.39), VAS (P = 0.24), and ROM (P = 0.37) among the groups revealed insignificant differences. All the studied groups showed a statistically significant trend of improvement in KSS, VAS, and ROM (P < 0.001), while the comparison of the three groups in terms of KSS (P = 0.001), VAS (P < 0.001), and ROM (P < 0.001) revealed remarkable superiority of multimodal injection to the other treatments.

Conclusion

Preemptive periarticular multimodal drug injection, including bupivacaine, morphine, epinephrine, and ketorolac, can cause considerable postoperative pain relief and better ROM achievement in comparison to placebo or oral celecoxib.

Strategies Tackling Viral Replication and Inflammatory Pathways as Early Pharmacological Treatment for SARS-CoV-2 Infection: Any Potential Role for Ketoprofen Lysine Salt?

COVID-19 is an infective disease resulting in widespread respiratory and non-respiratory symptoms prompted by SARS-CoV-2 infection. Interaction between SARS-CoV-2 and host cell receptors prompts activation of pro-inflammatory pathways which are involved in epithelial and endothelial damage mechanisms even after viral clearance. Since inflammation has been recognized as a critical step in COVID-19, anti-inflammatory therapies, including both steroids and non-steroids as well as cytokine inhibitors, have been proposed. Early treatment of COVID-19 has the potential to affect the clinical course of the disease regardless of underlying comorbid conditions. Non-steroidal anti-inflammatory drugs (NSAIDs), which are widely used for symptomatic relief of upper airway infections, became the mainstay of early phase treatment of COVID-19. In this review, we discuss the current evidence for using NSAIDs in early phases of SARS-CoV-2 infection with focus on ketoprofen lysine salt based on its pharmacodynamic and pharmacokinetic features.

Comparative evaluation of anti-inflammatory activity between n-butanol fraction, leaf and stem methanolic extract obtained from Olaxpsittacorum

ETHNOPHARMACOLOGICAL RELEVANCE

Olax psittacorum (Lam.) Vahl. traditionally used by the tribal communities of 'INDIA' to heal conditions such as pain, psoriasis, mouthulcer, anemia, constipation as well as diabetes followed by scientific evidences like antipyretic, anti-inflammatory, antimicrobial, anti-viral, and anti-cancer property too.

AIM OF THE EXPERIMENT

Solvent fractionation process by using chloroform, distilled water and n-butanol has been developed to get the precipitate as a fraction (encrypted as FrAE-ISO) of leaf methanolic extract (LME) and established GC-MS and antiinflammatory evaluation. The aim was to enumerate the potency against inflammation of FrAE-ISO comparing with LME, SME (Stem methanolic extract) and Diclofenac. TLC of LME extract has been developed too for separation & evaluation of the compounds appeared as bands obtained by scraping process. The motive of the experiment was to acquire an isolate from LME that can able to show an emense anti-inflammatory action compared to LME and SME.

MATERIALS AND METHODS

Priliminary phytochemical screening upon LME, SME and FrAE-ISO preformed by the standard methods of literatures. Scrapped portions of developed TLC plate (G-254 graded silica) of LME (n-Hexane:Ethylacetate; 7.5:2.5) were introduced to GC-MS evaluation. FrAE-ISO has introduced at a minute quantity (5 and 10 mg/kg/bw) within Wister albino rats (per os) against inflammation (model: carrageenan-induced paw edema) to evaluate its potency as compared to LME (25 mg/kg/bw), SME (25 mg/kg/bw) and Diclofenac (100 mg/kg). GC-MS evaluation has been conducted in both FrAE-ISO and scrapped sections to evaluate the presence of compounds qualitatively.

RESULTS

LME and SME, qualitatively through different screening processes confirm the presence of glycosides, flavonoids, amino acids, tannins, and saponins respectively. According to the quantitative study of the extracts concerning total phenolic, flavonoid, tannin, and saponin content equivalent to gallic acid, quercetin, tannic acid, and diosgenin respectively have shown less amount of phenolic, flavonoid, and saponin content in SME (30.95, 205.33 and 30.82 mg/g extract respectively) as compared to LME (95.68, 713.33 and 66.41 mg/g extract respectively). Quantitative estimation has shown the presence of 825.27 mg of saponin equivalent to diosgenin per gram of FrAE-ISO. The GC-MS study has revealed that every section of the leaf extract has " Hexadecanoic acid, methyl ester " in common with other important compounds responsible for its potent contribution towards the anti-inflammatory property. The scrapped portions of the TLC plate having mixture of compounds but FrAE-ISO has shown a sharp peak in GC-MS (up to 34 min of run time) as well as few crystals like structures under the binocular microscope. Compact doses of FrAEISO (yield = 1.645%) i.e. 5 and 10 mg/kg body weight was able to compete with 100 mg/kg Diclofenac portraying 88%-95% inhibition respectively throughout all phases of inflammation with no-significant differences compared to standard evaluated by ANOVA (in SPSS).

CONCLUSION

Olax psittacorum (Lam.) Vahl. could be a good choice to explore its importance within the pharmacognostic field of drug development and might be a better source of herbal-derived lead compounds which can help to treat other various activities like ulcer healing or anti-anemic property etc.

How effective is periarticular multimodal drug injection in open elbow arthrolysis? A prospective double-blind randomized controlled trial

BACKGROUND

Evidence on the efficacy and safety of periarticular multimodal drug injection (PMDI) in open elbow arthrolysis (OEA) is limited. This study aimed to investigate differences in postoperative pain, blood loss, and range of motion (ROM) between PMDI vs. no injection among patients undergoing OEA, and the presence of PMDI-related complications.

METHODS

This prospective, double-blind randomized controlled trial included 59 patients who underwent OEA. Patients randomly received PMDI (ropivacaine, epinephrine, ketoprofen) before wound closure or no injection. The primary outcomes were elbow pain over the first postoperative week at rest and during motion, measured using the visual analog scale (VAS). VAS scores were compared to attain the 20-mm threshold values for a minimum clinically important difference. Parecoxib consumption on OEA night and postoperative days (PODs) 1-3 and total consumption during the first postoperative week were recorded. Blood loss was recorded every 24 hours until POD 3. ROM during rehabilitation was measured daily from day 1 to day 7 after surgery, as well as at 3-month follow-up. Medication-related side effects were recorded prospectively.

RESULTS

The mean VAS score showed clinically important differences between PMDI and control groups at rest on OEA night (mean difference [MD], 25 mm; P < .001) and first 3 PODs with motion (POD 1: MD, 28 mm, P < .001; POD 2: MD, 21 mm, P < .001; POD 3: MD, 21 mm, P < .001) but not in other postoperative assessments. Parecoxib consumption was lower in the PMDI group on OEA night and PODs 1-3. Total parecoxib consumption during the first postoperative week was lower in the PMDI group vs. the control group (MD, 148 mg; P < .001). Blood drainage was less in the PMDI group vs. the control group on POD 1 (MD, 38 mL; P = .016) but not on POD 2 (P = .950), POD 3 (P = .259), or total (P = .184). The PMDI group exhibited significantly better ROM during the first 4 PODs than the control group, whereas there was no difference at 3-month follow-up. No medication-related side effects were noted in the PMDI group.

CONCLUSION

PMDI effectively relieves pain and reduces analgesic consumption for OEA patients, without an apparent increase in risks.

Spezielle Schmerztherapie bei rheumatischen Erkrankungen

Schmerz als Hauptsymptom vieler chronisch-entzündlicher Erkrankungen stellt für den Patienten, aber auch für den behandelnden Arzt besonders in seiner chronifizierten Form eine große Herausforderung dar. Es gibt leider keine „Wunderpille“ mit der man Schmerzen für jeden gleich zuverlässig beseitigen kann. Es gibt aber viele Ansätze pharmakologischer als auch nicht-pharmakologischer Art und deren Kombination, um für den einzelnen Patienten wirksame Behandlungsstrategien zu finden. Um diese Strategien für jeden Patienten individuell optimal festzulegen, bedarf es zum einen eines fundamentierten Wissens über das Spektrum zur Verfügung stehender Mittel, zum anderen aber auch Erkenntnis darüber, wie diese sinnvoll nach Art der vorliegenden Schmerzformen einzusetzen sind. In dieser Übersicht wird beides behandelt, mit einem Fokus auf die medikamentöse Therapie von Schmerzen bei entzündlich-rheumatischen Erkrankungen. Dabei wird herausgearbeitet, dass es für die in diesem Zusammenhang relevantesten Formen des Schmerzes, akut-entzündlich nozizeptiv, neuropathisch und durch periphere und zentrale Sensibilisierung chronifizierte Schmerzen, jeweils andere wirksame Konzepte gibt.

Inhibition of Fast Nerve Conduction Produced by Analgesics and Analgesic Adjuvants-Possible Involvement in Pain Alleviation

Nociceptive information is transmitted from the periphery to the cerebral cortex mainly by action potential (AP) conduction in nerve fibers and chemical transmission at synapses. Although this nociceptive transmission is largely inhibited at synapses by analgesics and their adjuvants, it is possible that the antinociceptive drugs inhibit nerve AP conduction, contributing to their antinociceptive effects. Many of the drugs are reported to inhibit the nerve conduction of AP and voltage-gated Na⁺ and K⁺ channels involved in its production. Compound action potential (CAP) is a useful measure to know whether drugs act on nerve AP conduction. Clinically-used analgesics and analgesic adjuvants (opioids, non-steroidal anti-inflammatory drugs, ₂-adrenoceptor agonists, antiepileptics, antidepressants and local anesthetics) were found to inhibit fast-conducting CAPs recorded from the frog sciatic nerve by using the air-gap method. Similar actions were produced by antinociceptive plant-derived chemicals. Their inhibitory actions depended on the concentrations and chemical structures of the drugs. This review article will mention the inhibitory actions of the antinociceptive compounds on CAPs in frog and mammalian peripheral (particularly, sciatic) nerves and on voltage-gated Na⁺ and K⁺ channels involved in AP production. Nerve AP conduction inhibition produced by analgesics and analgesic adjuvants is suggested to contribute to at least a part of their antinociceptive effects.

Towards an Effective and Safe Treatment of Inflammatory Pain: A Delphi-Guided Expert Consensus

OBJECTIVE

The clinical management of inflammatory pain requires an optimal balance between effective analgesia and associated safety risks. To date, mechanisms associated with inflammatory pain are not completely understood because of their complex nature and the involvement of both peripheral and central mechanisms. This Expert Consensus document is intended to update clinicians about evolving areas of clinical practice and/or available treatment options for the management of patients with inflammatory pain.

METHOD

An international group of experts in pain management covering the pharmacology, neurology and rheumatology fields carried out an independent qualitative systematic literature search using MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials.

RESULTS

Existing guidelines for pain management provide recommendations that do not satisfactorily address the complex nature of pain. To achieve optimal outcomes, drug choices should be individualized to guarantee the best match between the characteristics of the patient and the properties of the medication. NSAIDs represent an important prescribing choice in the management of inflammatory pain, and the recent results on paracetamol question its appropriate use in clinical practice, raising the need for re-evaluation of the recommendations in the clinical practice guidelines.

CONCLUSIONS

Increasing clinicians' knowledge of the available pharmacologic options to treat different pain mechanisms offers the potential for safe, individualized treatment decisions. We hope that it will help implement the needed changes in the management of inflammatory pain by providing the best strategies and new insights to achieve the ultimate goal of managing the disease and obtaining optimal benefits for patients.

FUNDING

Dompé Farmaceutici SPA and Paolo Procacci Foundation.

Radical cyanomethylation via vinyl azide cascade-fragmentation

Herein, a novel methodology for radical cyanomethylation is described. The process is initiated by radical addition to the vinyl azide reagent 3-azido-2-methylbut-3-en-2-ol which triggers a cascade-fragmentation mechanism driven by the loss of dinitrogen and the stabilised 2-hydroxypropyl radical, ultimately effecting cyanomethylation. Cyanomethyl groups can be efficiently introduced into a range of substrates via trapping of α-carbonyl, heterobenzylic, alkyl, sulfonyl and aryl radicals, generated from a variety of functional groups under both photoredox catalysis and non-catalytic conditions. The value of this approach is exemplified by the late-stage cyanomethylation of pharmaceuticals.

Effects of Pranoprofen on Aqueous Humor Monocyte Chemoattractant Protein-1 Level and Pain Relief During Second-Eye Cataract Surgery

The aim of our present study is to evaluate the efficacy of pranoprofen eye drops as pain relief during sequential second-eye cataract surgery and to investigate the possible mechanism. Seventy-six patients scheduled for bilateral sequential cataract surgery were randomly assigned to two groups: (1) treatment group (administered pranoprofen eye drops), or (2) control group (administered artificial tears). Preoperative anxiety and intraoperative pain were assessed. Monocyte chemoattractant protein 1 (MCP-1) in the aqueous humor was measured with a suspension cytokine array. An extracapsular lens extraction model was established in the Wistar rat and the MCP-1 concentrations were measured with an enzyme-linked immunosorbent assay. We found that in the control group, the pain scores were significantly higher during second-eye surgery than during first-eye surgery (both scores P < 0.001). In the treatment group, there was no significant difference in the pain scores during first-eye and second-eye surgery (both scores P > 0.1). The pain during second-eye surgery was significantly lower in the treatment group than in the control group (both scores P < 0.01). And in the 1-week and 6-week interval subgroups, the pain scores during second-eye surgery were significantly lower in the treatment group than the control group (P = 0.047 and P = 0.035, respectively). While the second-eye MCP-1 level was significantly lower after a 1-week interval in the treatment group than in the control group (P = 0.012), but did not differ significantly after a 6-week interval (P > 0.1). A parallel trend in the MCP-1 concentration was detected in the rat model. In conclusion, the preoperative administration of pranoprofen eye drops reduced the perceived pain during second-eye cataract surgery, especially when performed after 1-week and 6-week intervals between the first-eye and second-eye surgery. MCP-1, a pain-related cytokine, was associated with the pain-relief mechanism of pranoprofen when second-eye surgery was performed 1 week after second-eye surgery.

Inhibition by non-steroidal anti-inflammatory drugs of compound action potentials in frog sciatic nerve fibers

AIMS

Although antinociception produced by non-steroidal anti-inflammatory drugs (NSAIDs) is partly attributed to nerve conduction inhibition, this has not been thoroughly examined yet. The aim of the present study was to reveal quantitatively how various types of NSAIDs affect compound action potentials (CAPs), a measure of nerve conduction.

MAIN METHODS

CAPs were recorded from the frog sciatic nerve by using the air-gap method.

KEY FINDINGS

Soaking the sciatic nerve with acetic acid-based NSAIDs (diclofenac and aceclofenac) reduced the peak amplitude of CAP in a concentration-dependent manner; their IC₅₀ values were 0.94 and 0.47 mM, respectively. Other acetic acid-based NSAIDs (indomethacin, acemetacin and etodolac) also inhibited CAPs [the extent of inhibition: some 40% (1 mM), 40% (0.5 mM) and 15% (1 mM), respectively], except for sulindac and felbinac at 1 mM that had no effects on CAP peak amplitudes. A similar inhibition was produced by fenamic acid-based NSAIDs [tolfenamic acid (IC₅₀ = 0.29 mM), meclofenamic acid (0.19 mM), flufenamic acid (0.22 mM) and mefenamic acid] which are similar in chemical structure to diclofenac and aceclofenac; their derivatives (2,6-dichlorodiphenylamine and N-phenylanthranilic acid) also inhibited. On the other hand, salicylic acid-based (aspirin), propionic acid-based (ketoprofen, naproxen, ibuprofen, loxoprofen and flurbiprofen) and enolic acid-based (meloxicam and piroxicam) NSAIDs had no effects on CAP peak amplitudes.

SIGNIFICANCE

At least a part of antinociception produced by NSAIDs used as a dermatological drug to alleviate pain may be attributed to their inhibitory effects on nerve conduction, which depend on the chemical structures of NSAIDs.

Efficacy of multimodal drug injection after supramalleolar osteotomy for varus ankle osteoarthritis: A prospective randomized study

BACKGROUND

Optimal management of postoperative pain is important to ensure patient comfort and functional improvement. Despite the frequent use of multimodal drug injection for pain control after orthopedic surgery, few studies have evaluated its use after supramalleolar osteotomy.

METHODS

Supramalleolar osteotomy was performed in 62 patients (65 ankles). Thirty patients (31 ankles) were randomly assigned to receive multimodal drug injection (injection group) and 32 patients (34 ankles) were assigned to receive no multimodal drug injection (control group). The two groups were compared with regard to the degree of postoperative pain, the number of times patients pushed the patient-controlled analgesia (PCA) button, the total amount of fentanyl administered, and the frequency of additional diclofenac sodium injections.

RESULTS

The injection group had significant pain reduction during the first 36 postoperative hours compared to the control group. There were significant differences between the groups in the number of times that patients pushed the PCA button as well as the total amount of fentanyl administered up to 24 h postoperatively. The mean frequency of additional diclofenac sodium injections in the first 12 postoperative hours was significantly less in the injection group compared to that in the control group.

CONCLUSION

Multimodal drug injection was effective in reducing pain and decreasing both fentanyl and diclofenac sodium usage in patients undergoing supramalleolar osteotomy. Therefore, multimodal drug injection should be considered for improved pain control and patient comfort in the early postoperative period after supramalleolar osteotomy.

Cerebral analgesic response to nonsteroidal anti-inflammatory drug ibuprofen

Nonopioid agents, such as nonsteroidal anti-inflammatory drugs (NSAIDs), are the most commonly used class of analgesics. Increasing evidence suggests that cyclooxygenase (COX) inhibition at both peripheral and central sites can contribute to the antihyperalgesic effects of NSAIDs, with the predominant clinical effect being mediated centrally. In this study, we examined the cerebral response to ibuprofen in presurgical and postsurgical states and looked at the analgesic interaction between surgical state and treatment. We used an established clinical pain model involving third molar extraction, and quantitative arterial spin labelling (ASL) imaging to measure changes in tonic/ongoing neural activity. Concurrent to the ASL scans, we presented visual analogue scales inside the scanner to evaluate the subjective experience of pain. This novel methodology was incorporated into a randomized double-blind placebo-controlled design, with an open method of drug administration. We found that independent of its antinociceptive action, ibuprofen has no effect on regional cerebral blood flow under pain-free conditions (presurgery). However, in the postsurgical state, we observed increased activation of top-down modulatory circuits, which was accompanied by decreases in the areas engaged because of ongoing pain. Our findings demonstrate that ibuprofen has a measurable analgesic response in the human brain, with the subjective effects of pain relief reflected in two distinct brain networks. The observed activation of descending modulatory circuits warrants further investigation, as this may provide new insights into the inhibitory mechanisms of analgesia that might be exploited to improve safety and efficacy in pain management.

Indomethacin inhibits tetrodotoxin-resistant Na(+) channels at acidic pH in rat nociceptive neurons

Non-steroidal anti-inflammatory drugs (NSAIDs) are well-known inhibitors of cyclooxygenases (COXs) and are widely used for the treatment of inflammatory pain; however several NSAIDs display COX-independent analgesic action including the inhibition of voltage-gated Na(+) channels expressed in primary afferent neurons. In the present study, we examined whether NSAIDs modulate tetrodotoxin-resistant (TTX-R) Na(+) channels and if this modulation depends on the extracellular pH. The TTX-R Na(+) currents were recorded from small-sized trigeminal ganglion neurons by using a whole-cell patch clamp technique. Among eight NSAIDs tested in this study, several drugs, including aspirin and ibuprofen, did not affect TTX-R Na(+) channels either at pH 7.4 or at pH 6.0. However, we found that indomethacin, and, to a lesser extent, ibuprofen and naproxen potently inhibited the peak amplitude of TTX-R Na(+) currents at pH 6.0. The indomethacin-induced inhibition of TTX-R Na(+) channels was more potent at depolarized membrane potentials. Indomethacin significantly shifted both the voltage-activation and voltage-inactivation relationships to depolarizing potentials at pH 6.0. Indomethacin accelerated the development of inactivation and retarded the recovery from inactivation of TTX-R Na(+) channels at pH 6.0. Given that indomethacin and several other NSAIDs could further suppress local nociceptive signals by inhibiting TTX-R Na(+) channels at an acidic pH in addition to the classical COX inhibition, these drugs could be particularly useful for the treatment of inflammatory pain.

Comparison of clinical efficacy of intravenous acetaminophen with intravenous morphine in acute renal colic: a randomized, double-blind, controlled trial

The aim of this study was to compare the clinical efficacy of intravenous acetaminophen with intravenous morphine in acute renal colic pain management. In this double-blind controlled trial, patients aged 18–55 years, diagnosed with acute renal colic, who met the inclusion and exclusion criteria, were randomized into two groups. First, using the visual analogue scale (VAS), intensity of pain was assessed in both groups. Then, one gram of intravenous acetaminophen or 0.1 mg/kg morphine was infused in 100 mL normal saline to either acetaminophen or morphine group. Intensity of pain was reassessed in 15, 30, 45, and 60 minutes according to VAS criteria. Finally, data from 108 patients were analyzed, 54 patients in each group. No significant difference was observed between the two groups in regard to sex (P = 0.13), mean age (P = 0.54), and baseline visual analogue score (P = 0.21). A repeated measure analysis of variance revealed that the difference between the two treatments was significant (P = 0.0001). The VAS reduction at primary endpoint (30 min after drug administration) was significantly higher in the acetaminophen group than in the morphine group (P = 0.0001). This study demonstrated that intravenous acetaminophen could be more effective than intravenous morphine in acute renal colic patients' pain relief.

A study to compare circulating flunixin, meloxicam and gabapentin concentrations with prostaglandin E₂ levels in calves undergoing dehorning

The purpose of this study was to investigate the pharmacokinetics of intravenous flunixin (2.2 mg/kg b.w.), oral meloxicam (1mg/kg b.w.), oral gabapentin (15 mg/kg b.w.) alone or co-administrated with meloxicam as well as the effects of these compounds on prostaglandin E2 (PGE2) synthesis in calves subjected to surgical dehorning. Plasma samples collected up to 24h after drug administration were analyzed by liquid chromatography/mass spectrometry, whereas blood PGE2 levels were measured by immunoenzymatic assay. In plasma, the terminal half-live of flunixin, meloxicam and gabapentin were 6.0 h (range, 3.4-11.0 h), 16.7h (range, 13.7-21.3h) and 15.3h (range, 11-32.9h), respectively. The co-administration of single doses of gabapentin and meloxicam did not seem to affect the pharmacokinetic profile of the two drugs except for gabapentin that reached significantly (P<0.05) higher maximum serum concentration (Cmax) when co-administered with meloxicam, than when administered alone. At 5, 360 and 720 min after dehorning, a significant (P<0.01) decrease in PGE2 concentration was observed in flunixin-treated animals compared with control calves. Moreover, circulating log PGE2 concentrations were inversely proportional to log flunixin concentrations (R(2)=0.75; P<0.0001). None of the other drugs significantly affected blood PGE2 levels. Further assessment of oral meloxicam and gabapentin in established pain models is required to formulate science based analgesic recommendations to enhance animal well-being after dehorning.

Insights into the effects of diclofenac and other non-steroidal anti-inflammatory agents on ion channels

OBJECTIVES

Diclofenac and other non-steroidal anti-inflammatory drugs (NSAIDs) are widely used in the treatment of inflammation and pain. Most effects of NSAIDs are attributed to the inhibition of cyclooxygenases (COX). However, many NSAIDs may have other effects not related to COX, including the modulation of various ion channels. The clinical implications of the effects on channels are not fully understood. This review outlines the effects of NSAIDs, with special attention to diclofenac, on ion channels and highlights the possible underlying mechanisms.

KEY FINDINGS

NSAIDs have effects on channels such as inhibition, activation or changes in expression patterns. The channels affected include voltage-gated Na(+) , Ca(2+) , or K(+) channels, ligand-gated K(+) channels, transient receptor potential and other cation channels as well as chloride channels in several types of cells. The mechanisms of drug actions not related to COX inhibition may involve drug-channel interactions, interference with the generation of second messengers, changes in channel expression, or synergistic/antagonist interactions with other channel modulators.

SUMMARY

The effects on ion channels may account for novel therapeutic actions of NSAIDs or for adverse effects. Among the NSAIDs, diclofenac may serve as a template for developing new channel modulators and as a tool for investigating the actions of other drugs.

Comparison of multi-drug injection versus placebo after hallux valgus surgery

BACKGROUND

Hallux valgus surgery is followed by a significant amount of postoperative pain. Local multi-drug injection can be an option for pain control, but few clinical studies exist.

METHODS

Between May 2008 and July 2009, 30 consecutive patients (60 feet) received simultaneous bilateral proximal osteotomies for the correction of hallux valgus deformities. Each patient received local infiltration of the test solution made with ropivacaine, morphine, ketorolac, and epinephrine on one foot and same amount of normal saline on the other foot. The test side and the control side were randomly selected and both the patient and the surgeon remained blinded until the end of the data collection.

RESULTS

The multi-drug injection resulted in significantly less pain at 4 hours after the operation through the night of the first postoperative day. The difference in visual analogue scale (VAS) between the two sides was most significant at 8 hours after the operation, and then gradually decreased through the first and second postoperative day. Mean satisfaction VAS was significantly higher on the injection side (8.2+/-0.9) compared to the control side (6.2+/-1.9, p<0.0001).

CONCLUSION

Local multi-drug injection was easy to perform and safe and effective in reducing pain and enhancing patient satisfaction after hallux valgus surgery.

Acute castration and/or tailing distress and its alleviation in lambs

PURPOSES AND APPROACH: Acute castration and/or tailing distress in lambs has been examined extensively during the last decade. At least 59 different approaches to assessing and alleviating this distress have been reported so that the literature is quite complex. The purpose of this paper is to provide an overview of the literature on castration and/or tailing distress, where the distress was assessed using acute changes in plasma cortisol concentrations. A method of analysis involving the integrated cortisol response (i.e. the areas under the cortisol curves while the plasma concentration is above pretreatment values) to each treatment and using treatments which were common to different studies as reference points, allowed meaningful comparison within and between studies. A 6-point ranking scale emerged, where rank 1 represented the least distress and rank 6 the most distress.

COMPARISON OF ACUTE DISTRESS RESPONSES

This analysis revealed the following major points. Surgical methods of castration and/or tailing cause the greatest cortisol responses (rank 5 or 6). Most ring and ring plus clamp methods of castration plus tailing or castration, used without a local anaesthetic or systemic analgesic, cause rank 4 responses. One form of ring plus clamp castration (i.e. applying the clamp for 10 s across the full width of the scrotum distal to the ring in lambs aged no more than 1 week) reduces the cortisol response to rank 1. When these lambs are also tailed by applying a ring and clamp in a similar manner to the tail, they also exhibit a rank 1 response. Local anaesthetic given 10-20 or 12 min or 10-15 s before or immediately after ring only castration and/or tailing can virtually abolish the cortisol response (rank 1), depending on the site(s) of injection. For ring or ring plus clamp castration, the most effective sites (as judged by cortisol responses) are the neck of the scrotum or the testes. Delivery of local anaesthetic to achieve successful nerve blockade can be by needle, high-pressure needleless administration or, for the tail only, by an aerosol spray. Local anaesthetic injected into the scrotal neck, spermatic cords and/or testes has little effect on the overall cortisol response to clamp castration. Reductions in cortisol responses to clamp castration or to ring tailing can occur after administration of non-steroidal anti-inflammatory drugs. Most tailing methods elicit cortisol responses that are several ranks lower than those caused by castration plus tailing or castration alone. Although tailing by most methods elicits rank 1 cortisol responses, the use of local anaesthetic or non-steroidal anti-inflammatory drugs can reduce the response within the rank 1 range.

RECOMMENDATION

Farmers should be encouraged to choose the lowest ranked method that is economically and practically feasible for them. Specific methods such as surgical castration should be discouraged.

Ketoprofen in piglets: enantioselective pharmacokinetics, pharmacodynamics and PK/PD modelling

The chiral pharmacokinetics and pharmacodynamics of ketoprofen were investigated in a placebo-controlled study in piglets after intramuscular administration of 6 mg/kg racemic ketoprofen. The absorption half-lives of both enantiomers were short, and S-ketoprofen predominated over R-ketoprofen in plasma. A kaolin-induced inflammation model was used to evaluate the anti-inflammatory, antipyretic and analgesic effects of ketoprofen. Skin temperatures increased after the kaolin injection, but the effect of ketoprofen was small. No significant antipyretic effects could be detected, but body temperatures tended to be lower in the ketoprofen-treated piglets. Mechanical nociceptive threshold testing was used to evaluate the analgesic effects. The piglets in the ketoprofen-treated group had significantly higher mechanical nociceptive thresholds compared to the piglets in the placebo group for 12-24 h following the treatment. Pharmacokinetic/pharmacodynamic modelling of the results from the mechanical nociceptive threshold testing gave a median IC(50) for S-ketoprofen of 26.7 μg/mL and an IC(50) for R-ketoprofen of 1.6 μg/mL. This indicates that R-ketoprofen is a more potent analgesic than S-ketoprofen in piglets. Estimated ED(50) for racemic ketoprofen was 2.5 mg/kg.

Diclofenac: an update on its mechanism of action and safety profile

BACKGROUND

Diclofenac is a proven, commonly prescribed nonsteroidal anti-inflammatory drug (NSAID) that has analgesic, anti-inflammatory, and antipyretic properties, and has been shown to be effective in treating a variety of acute and chronic pain and inflammatory conditions. As with all NSAIDs, diclofenac exerts its action via inhibition of prostaglandin synthesis by inhibiting cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) with relative equipotency. However, extensive research shows the pharmacologic activity of diclofenac goes beyond COX inhibition, and includes multimodal and, in some instances, novel mechanisms of action (MOA).

DATA SOURCES

Literature retrieval was performed through PubMed/MEDLINE (through May 2009) using combinations of the terms diclofenac, NSAID, mechanism of action, COX-1, COX-2, and pharmacology. Reference citations resulting from publications identified in the literature search were reviewed when appropriate.

METHODS

This article reviews the established, putative, and emerging MOAs of diclofenac; compares the drug's pharmacologic and pharmacodynamic properties with other NSAIDs to delineate its potentially unique qualities; hypothesizes why it has been chosen for further recent formulation enhancement; and evaluates the potential effect of its MOA characteristics on safety.

DISCUSSION

Research suggests diclofenac can inhibit the thromboxane-prostanoid receptor, affect arachidonic acid release and uptake, inhibit lipoxygenase enzymes, and activate the nitric oxide-cGMP antinociceptive pathway. Other novel MOAs may include the inhibition of substrate P, inhibition of peroxisome proliferator activated receptor gamma (PPARgamma), blockage of acid-sensing ion channels, alteration of interleukin-6 production, and inhibition of N-methyl-D-aspartate (NMDA) receptor hyperalgesia. The review was not designed to compare MOAs of diclofenac with other NSAIDs. Additionally, as the highlighted putative and emerging MOAs do not have clinical data to demonstrate that these models are correct, further research is necessary to ascertain if the proposed pathways will translate into clinical benefits. The diversity in diclofenac's MOA may suggest the potential for a relatively more favorable profile compared with other NSAIDs.

Mechanisms of non-opioid analgesics beyond cyclooxygenase enzyme inhibition

Non-opioid analgesics including both selective and non-selective cyclooxygenase (COX) inhibitors and acetaminophen are the most widely used treatments for pain. Inhibition of COX is thought to be largely responsible for both the therapeutic and adverse effects of this class of drugs. Accumulating evidence over the past two decades has demonstrated effects of non-opioids beyond the inhibition of COX and prostaglandin synthesis that might also explain their therapeutic and adverse effects. These include their interaction with endocannabinoids, nitric oxide, monoaminergic, and cholinergic systems. Moreover, the recent development of microarray technology that allows the study of human gene expression suggests multiple pathways that may be related to the analgesic and anti-inflammatory effects of non-opioids. The present review will discuss the multiple actions of non-opioids and their interactions with these systems during inflammation and pain, suggesting that COX inhibition is an incomplete explanation for the actions of non-opioids and proposes the involvement of multiple selective targets for their analgesic, as well as, their adverse effects.

[Postoperative use of nonsteroidal anti-inflammatory agents in orthopedic surgery]

Nonsteroidal antiinflamatory drugs (NSAIDs) lead to satisfactory acute and chronic pain relief. Besides that, they exert potent antiinflamatory effect. Their analgesic potency is dose related and limited. Orthopedic patients are often on these medications preoperatively and experience opioid-sparing effect in the postoperative period. Chronic NSAIDs use is related to higher rate of sistemic adverse effects, but even short time exposure in the postoperative period is not risk-free. Although Coxibs reduce GIT bleeding incidence due to prolonged use of NSAIDs, there has to be judicious decision considering their cardiovascular adverse effects. There is evidence that NSAIDs producing moderate, dose-dependent increased bleeding time within normal values. High risk of bleeding have patients with established coagulopathy, alcohol abuse and on anticoagulant treatment. There is no strong evidence on influence of NSAIDs on bone growth. Nevertheless, there is evidence that NSAIDs do prevent heterotropic ossification. Prostaglandins are vital contributors for maintainig tissue homeostasis and NSAIDs use can lead to many unwanted effects. Those adverse effect are more common with prolonged exposure, are dose-related and risks have to be carefully and individually assesed in the postoperative pain management.

Use of a pharmacokinetic/pharmacodynamic approach in the cat to determine a dosage regimen for the COX-2 selective drug robenacoxib

This study investigated the analgesic, anti-inflammatory and antipyretic efficacy of the new COX-2 selective inhibitor robenacoxib in the cat and established pharmacodynamic (PD) parameters for these effects. Robenacoxib, at a dosage of 2 mg/kg administered subcutaneously, was evaluated in a kaolin-induced paw inflammation model in 10 cats, using both clinically relevant endpoints (lameness scoring, locomotion tests) and other indicators of inflammation (body and skin temperature, thermal pain threshold) to establish its pharmacological profile. A pharmacokinetic/pharmacodynamic (PK/PD) modelling approach, based on indirect response models, was used to describe the time course and magnitude of the responses to robenacoxib. All endpoints demonstrated good responsiveness to robenacoxib administration and both the magnitude and time courses of responses were well described by the indirect pharmacodynamic response models. Pharmacokinetic and clinically relevant pharmacodynamic parameters were used to simulate dosage regimens that will assist the planning of clinical trials and the selection of an optimal dosage regimen for robenacoxib in the cat.

The effects and safety of dexibuprofen compared with ibuprofen in febrile children caused by upper respiratory tract infection

AIM

To evaluate the antipyretic efficacy and tolerability of dexibuprofen compared with ibuprofen in children with fever caused by upper respiratory tract infection (URTI).

METHODS

The study population consisted of children aged 6 months to 14 years. At the time of visit to the hospital, the children had fever; the cause of fever was determined to be URTI by a paediatrician based on history taking and physical examination. The study was a multicentre, randomized, double-blind, controlled parallel group, comparative, Phase 3 clinical trial, conducted at three hospitals. By using a computer-based random assignment program, the subjects were allocated to the following three groups: 5 mg kg(-1) dexibuprofen group, 7 mg kg(-1) dexibuprofen group, and 10 mg kg(-1) ibuprofen group.

RESULTS

In the clinical trial of the antipyretic action of dexibuprofen in patients with fever caused by URTI, there was no statistically significant difference in maximal decrease of temperature and mean time to become apyrexial among the 5 mg kg(-1) dexibuprofen, 7 mg kg(-1) dexibuprofen and 10 mg kg(-1) ibuprofen groups (P > 0.05). There also was no significant difference in adverse drug reaction (P > 0.05).

CONCLUSIONS

Dexibuprofen is as effective and tolerable as ibuprofen. A dose of 5 mg kg(-1) and 7 mg kg(-1) dexibuprofen in place of 10 mg kg(-1) ibuprofen would be sufficient to control fever caused by URTI in children.

The analgesic efficacy of preoperative versus postoperative lornoxicam in varicocele repair

STUDY OBJECTIVE

To determine whether intravenous injection of lornoxicam 30 minutes before skin incision provides better pain relief after varicocelectomy than postoperative administration of lornoxicam.

DESIGN

Prospective, double-blind, randomized clinical investigation.

SETTING

Operating room and postoperative recovery area.

PATIENTS

44 ASA physical status I and II adult male patients undergoing varicocelectomy.

INTERVENTIONS

Patients were randomized either to receive 8 mg lornoxicam infusion 30 minutes before skin incision, followed by saline infusion immediately after skin closure (group 1), or to receive the identical injections but in reverse order (group 2). All patients received local anesthesia with bupivacaine.

MEASUREMENTS

Postoperative pain scores were evaluated hourly for the first 8 hours after surgery, then at 12, 16, 20, and 24 hours after surgery, using a 10-cm visual analog scale. Time to first analgesic request and patients' global assessments also were recorded.

MAIN RESULTS

Patients in group 1 reported significantly lower pain scores (P < 0.05) at all time intervals except at 24 hours and better global assessment (P = 0.001) than did group 2. There were significantly fewer patients in the preemptive group than group 2 who required rescue analgesic within the first 24 hours (0% vs 22.7%; P = 0.024). Mean time to first analgesic request was also significantly longer in the preemptive group (P = 0.001).

CONCLUSION

Intravenous lornoxicam administered before surgery has a better analgesic effect for varicocelectomy than when administered postoperatively.

Constitutive cyclooxygenase-2 is involved in central nociceptive processes in humans

BACKGROUND

Prostaglandins play a major role in inflammation and pain. They are synthesized by the two cyclooxygenase (COX) isoforms: COX-1, which is expressed constitutively in many cell types, and COX-2, which is induced at the site of inflammation. However, unlike peripheral tissues, COX-2 is expressed constitutively in the central nervous system and may play a role in nociceptive processes. The current study aimed to investigate the role of constitutive COX-2 in the spinal transmission of nociceptive signals in humans.

METHODS

The authors used 12 healthy volunteers to compare the effects of the specific COX-2 inhibitor sodium parecoxib (1 mg/kg) or placebo, administered intravenously in a double-blind and crossover fashion, on the electrophysiologic recordings of the nociceptive flexion (RIII) reflex. The RIII reflex is an objective psychophysiologic index of the spinal transmission of nociceptive signals and was recorded from the biceps femoris after electrical stimulation of the sural nerve. Two experiments, 7 days apart, were conducted in each volunteer. On each experimental day, the effects of parecoxib or placebo were tested on (1) the RIII reflex threshold, (2) the stimulus-response curves of the reflex up to the tolerance threshold (frequency of stimulation: 0.1 Hz), and (3) the progressive increase of the reflex and pain sensations (i.e., "windup" phenomenon) induced by a series of 15 stimulations at a frequency of 1 Hz (intensity 20% above RIII threshold).

RESULTS

Parecoxib, but not placebo, significantly reduced the slope of the stimulus-response curve, suggesting a reduction in the gain of the spinal transmission of nociceptive signals. By contrast, the windup phenomenon was not significantly altered after administration of parecoxib or placebo.

CONCLUSIONS

This study shows that constitutive COX-2 modulates spinal nociceptive processes and that the antiinflammatory and antinociceptive actions of COX-2 inhibitors are not necessarily related.

Is it safe to use topical NSAIDs for corneal sensitivity in Sjögren’s syndrome patients?

Sjögren's syndrome dry eye is an inflammatory disease accompanied by an impairment of the autonomous nervous system of the ocular surface. The therapy for this condition is shifting from the mere tear replacement to a more complex approach including an anti-inflammatory treatment. Clinical trials have evidenced that the use of NSAIDs is followed by a reduction of the ocular discomfort symptoms in dry-eye patients. However, sporadic case reports of corneal melting in dry-eye subjects who underwent surgical procedures has brought attention to the possible effect that NSAIDs may have on corneal sensitivity. Therefore, the effect of NSAID treatment on corneal sensitivity in normal subjects and in patients with dry eye was studied. The results of these trials seem to demonstrate that some NSAIDs, diclofenac in particular, have the effect of reducing corneal sensitivity both in normal subjects and in patients with dry eye. Therefore, NSAIDs should be used with caution in Sjögren's syndrome patients.

Comparison of the analgesic efficacy and safety of nepafenac ophthalmic suspension compared with diclofenac ophthalmic solution for ocular pain and photophobia after excimer laser surgery: a phase II, randomized, double-masked trial

OBJECTIVE

The aim of this study was to evaluate the efficacy and safety of nepafenac ophthalmic suspension 0.03% and 0.1% for the treatment of postoperative pain and photophobia in patients undergoing excimer photoreactive keratectomy (PRK).

METHODS

In this 7-day, randomized, double-masked, parallel-group trial at 2 sites, patients undergoing PRK surgery were randomly assigned to receive nepafenac ophthalmic suspension 0.03% or 0.1%, or diclofenac sodium ophthalmic solution 0.1%. Patients were treated on day 0 (surgery) and day 1 (the day after surgery). The dose regimen for all 3 treatments was the same. On day 0, patients received 2 drops in the operative eye -1 hour before surgery; 2 drops within 1 hour after surgery; 1 drop -4 hours after the first postoperative dose; and 1 drop -8 hours after the first postoperative dose. On day 1, patients instilled 1 drop of study drug QID. Thereafter, the study medication was discontinued. In the perioperative period, study personnel instilled the drops. The patients instilled the drops when they went home. Patients recorded pain and photophobia from day 0 through day 2, rating pain from 0 to 9 on a visual analog scale (0=none, 9=extreme) and photophobia from 0 to 3 on an ordinal, categoric scale (0=none, 3=severe). Patients were permitted to take acetaminophen 500 mg as needed for pain. They returned for postoperative follow-up visits on days 1, 3, and 7. Adverse events were documented when reported by the patients themselves, and when study personnel asked about specific events.

RESULTS

Sixty patients (20 per group) were enrolled. On the day of surgery, there were no significant differences between groups, except at 3 hours after surgery, when the nepafenac 0.03% group had a significantly higher mean pain score than the nepafenac 0.1% group (4.0 vs 3.0; P<0.038). On day 2, the nepafenac 0.1% group had less pain at bedtime than the diclofenac group (mean score, 1.9 vs 3.1; P<0.024) and less photophobia in the morning (mean score, 1.2 vs 1.8; P<0.023). For the nepafenac 0.03% group, the mean pain and mean photophobia scores were 2.5 and 1.6, respectively. There were no significant differences between the 3 treatment groups in the proportion of patients who took acetaminophen for pain at any time point (P=NS). There was no statistically significant difference in corneal re-epithelialization rates among the 3 groups. Adverse events were infrequent, and no serious adverse events occurred. Two ocular adverse events related to therapy occurred: a corneal infiltrate in 1 patient in the nepafenac 0.03% group; and ocular discomfort in 1 patient in the nepafenac 0.1% group. Both patients continued the study.

CONCLUSIONS

Both nepafenac 0.03% and 0.1% were effective for treatment of pain and photophobia in these patients undergoing PRK surgery. There was no difference in the proportion of patients who took rescue acetaminophen for pain. All treatments were well tolerated in these patients.

Efficacy of periarticular multimodal drug injection in total knee arthroplasty. A randomized trial

BACKGROUND

Postoperative analgesia with the use of parenteral opioids or epidural analgesia can be associated with troublesome side effects. Good perioperative analgesia facilitates rehabilitation, improves patient satisfaction, and may reduce the hospital stay. We investigated the analgesic effect of locally injected drugs around a total knee prosthesis.

METHODS

Sixty-four patients undergoing total knee arthroplasty were randomized either to receive a periarticular intraoperative injection containing ropivacaine, ketorolac, epimorphine, and epinephrine or to receive no injection. The perioperative analgesic regimen was standardized. All patients in both groups received patient-controlled analgesia for twenty-four hours after the surgery, and this was followed by standard analgesia. Visual analog scores for pain, during activity and at rest, and for patient satisfaction were recorded preoperatively and postoperatively and at the six-week follow-up examination. The consumption of patient-controlled analgesia at specific postoperative time-points and the overall analgesic requirement were measured.

RESULTS

The patients who had received the injection used significantly less patient-controlled analgesia at six hours, at twelve hours, and over the first twenty-four hours after the surgery. In addition, they had higher visual analog scores for patient satisfaction and lower visual analog scores for pain during activity in the post-anesthetic-care unit and four hours after the operation. No cardiac or central nervous system toxicity was observed.

CONCLUSIONS

Intraoperative periarticular injection with multimodal drugs can significantly reduce the requirements for patient-controlled analgesia and improve patient satisfaction, with no apparent risks, following total knee arthroplasty.

Hyperalgesia induced by cutaneous freeze injury for testing analgesics in healthy volunteers

AIMS

The early phases of the clinical development of new analgesic agents are severely hindered by a lack of reliable sensitive tests based on experimental pain models. The aim of this study was to assess the ability of a localized hyperalgesia model induced by cutaneous freeze injury to evaluate the pharmacodynamic profile of weak analgesic agents in healthy volunteers.

METHOD AND RESULTS

Two groups of 24 healthy volunteers were enrolled in controlled, randomized, double-blind, cross-over studies. After freeze injury, punctate mechanical pain thresholds (MPT) were measured over three consecutive daily sessions to characterize the induced hyperalgesia and compare the effects of (i) oral ibuprofen and acetaminophen and (ii) oral and topical ibuprofen vs. placebo. The freeze injury model provides two types of hyperalgesia, primary and secondary, stable over 72 h. The MPT values (means; 95% confidence interval) in the primary (38.9 g; 34.3, 43.5) and secondary (82.2 g; 81.4, 88.0) areas of hyperalgesia were different from normal skin (107.5 g; 101.5, 115.2). This model clearly showed the antihyperalgesic effect of both systemic and topical ibuprofen (42.1%; 26.6, 61.2 and 33.8%; 16.4, 51.2 of MPT increase, respectively) but not that of acetaminophen.

CONCLUSION

Cutaneous freeze injury coupled with a von Frey electronic device to assess the mechanical pain threshold is a convenient model that causes no discomfort. The improved sensitivity and stability of this experimental model of hyperalgesia over three consecutive days make it a useful tool for evaluating the efficacy and detecting the potential sites of action of analgesic agents such as nonsteroidal anti-inflammatory drugs in healthy human subjects.

Topical ketoprofen patch

Although oral nonsteroidal anti-inflammatory drugs (NSAIDs) are effective in the treatment of a variety of acute and chronic pain conditions, their use may be associated with serious systemic adverse effects, particularly gastrointestinal disorders. In order to minimise the incidence of systemic events related to such agents, topical NSAIDs have been developed. Topical NSAIDs, applied as gels, creams or sprays, penetrate the skin, subcutaneous fatty tissue and muscle in amounts that are sufficient to exert a therapeutic effect on peripheral and central mechanisms in the absence of high plasma concentrations. Data indicate that topical NSAIDs are effective at relieving pain in a number of acute and chronic pain indications. This review article discusses the pharmacokinetics, efficacy and tolerability of a new formulation of ketoprofen available as a topical patch. The topical patch containing ketoprofen 100mg as the active principle has been developed using a novel delivery system that dispenses therapeutic doses of the drug directly to the site of injury. Pharmacokinetic data indicate that although plasma levels of ketoprofen are higher when the drug is administered as a patch versus a gel, the total systemic bioavailability of ketoprofen 100 mg administered via a patch is no more than 10% of that reported for ketoprofen 100 mg administered orally. Because the patch facilitates ketoprofen delivery over a 24-hour period, the drug remains continually present in the tissue subjacent to the site of application. High tissue but low plasma ketoprofen concentrations mean that while tissue concentrations are high enough to exert a therapeutic effect, plasma concentrations remain low enough to not result in systemic adverse events caused by elevated serum NSAID levels. Phase III clinical trials in patients with non-articular rheumatism and traumatic painful soft tissue injuries showed that the topical ketoprofen patch was significantly more effective than placebo at reducing pain during daily activities and spontaneous pain after 7 days' treatment. Moreover, the topical ketoprofen patch was well tolerated; adverse events were primarily cutaneous in nature and occurred in a similar number of ketoprofen and placebo recipients suggesting that these events were related to the patch itself rather than the active ingredient. The incidence of gastrointestinal adverse events was low (<8% of all patients), and occurred in a similar proportion of patients receiving ketoprofen and placebo. Thus, the topical ketoprofen patch appears to be a simple, effective and safe therapeutic option for the treatment of local painful inflammation.

Effects of preoperative administration of carprofen on renal function and hemostasis in dogs undergoing surgery for fracture repair

OBJECTIVE

To evaluate effects of preoperative administration of carprofen on renal function and hemostasis in dogs undergoing general anesthesia for fracture repair.

ANIMALS

26 client-owned dogs.

PROCEDURE

Anesthesia was induced with levomethadone, diazepam, and propofol and maintained by administration of isoflurane in oxygen-nitrous oxide. Carprofen (4 mg/kg, SC) was administered 1 hour before induction to 13 dogs (group 1) and after extubation to the other 13 dogs (group 2). All dogs also received carprofen (4 mg/kg, SC, q 24 h) for the first 4 days after surgery. Renal function (glomerular filtration rate [GFR], urinary protein-to-urinary creatinine ratio [UP:UC], and results of urinalysis and biochemical analysis of plasma), hemostatic variables (bleeding time, platelet aggregation, prothrombin time [PT], activated partial thromboplastin time [APTT], and platelet count), and Hct were assessed before and at various time points after surgery.

RESULTS

Analysis of results for renal function tests, most of the hemostatic and plasma biochemical variables, and Hct did not reveal significant differences between treatment groups. Values for GFR, UP:UC, PT, APTT, and platelet aggregation were outside reference ranges in many dogs before surgery and during the first 6 hours after surgery. In most dogs, these trauma-induced pathologic changes returned to within reference ranges during the 4-day period after surgery.

CONCLUSIONS AND CLINICAL RELEVANCE

Carprofen did not cause clinically relevant adverse effects in dogs anesthetized for fracture repair after 5 days of treatment, even when it was administered before surgery or given to patients with trauma-induced alterations in renal function or hemostasis.

COX-dependent mechanisms involved in the antinociceptive action of NSAIDs at central and peripheral sites

Despite the diverse chemical structure of aspirin-like drugs, the antinociceptive effect of NSAIDs is mainly due to their common property of inhibiting cyclooxygenases involved in the formation of prostaglandins. Prostaglandins are potent hyperalgesic mediators which modulate multiple sites along the nociceptive pathway and enhance both transduction (peripheral sensitizing effect) and transmission (central sensitizing effect) of nociceptive information. Inhibition of the formation of prostaglandins at peripheral and central sites by NSAIDs thus leads to the normalisation of the increased pain threshold associated with inflammation. The contribution of peripheral and central mechanisms to the overall antinociceptive action of NSAIDs depends on several factors including the location of the targets of drug action, the site of drug delivery and the uptake and distribution to the site of action. The present work reviews the data on the regulation and location of cyclooxygenases at central and peripheral sites of the nociceptive pathway and focuses on the role of COX in the generation and maintenance of pain hypersensitivity. Experimental and clinical evidences are used to evaluate the significance of the peripheral and central antihyperalgesic effects of NSAIDs.

The pharmacokinetics of vedaprofen and its enantiomers in dogs after single and multiple dosing

Vedaprofen is a chiral nonsteroidal anti-inflammatory drug that has been developed as a gel formulation for oral administration to dogs and horses. The pharmacokinetics of vedaprofen and its enantiomers were studied in beagle dogs after single (intravenous solution and oral gel) and multiple (oral gel) dosing at a dosage of 0.5 mg/kg body weight. Plasma concentrations of vedaprofen and its enantiomers were analysed by HPLC. The plasma protein binding of vedaprofen was studied by ultrafiltration. The absorption of vedaprofen was rapid (tmax 0.63 +/- 0.14 h) and almost complete after oral administration (bioavailability 86 +/- 7%). The terminal half-lives after intravenous and oral administration, 16.8 +/- 2.2 and 12.7 +/- 1.7 h respectively, were of the same order of magnitude. Enantioselective analysis showed that the R(-) enantiomer predominated in plasma. The change in the plasma time course of the plasma R(-)/S(+) enantiomer concentration ratio over time was similar after single intravenous and oral dosing, with R(-)/S(+) ratios in the AUC of 1.7 +/- 0.5 and 1.9 +/- 0.2 respectively. Plasma protein binding of vedaprofen and its enantiomers was high (> 99.5%). Vedaprofen is absorbed rapidly from the gastrointestinal tract, has a high bioavailability and does not accumulate in plasma in dogs following repeated oral administration.

Dehorning and disbudding distress and its alleviation in calves

Dehorning and disbudding are routine painful procedures carried out on cattle to facilitate management. The pain caused by these procedures and its alleviation may be evaluated by monitoring behaviour and physiological responses, and by measuring their effects on weight gain. The cortisol response to cautery disbudding is significantly smaller than that to amputation dehorning which infers that the latter is more painful. Amputation dehorning stimulates a defined cortisol response with a rapid rise to a peak value within 30 min followed by a decline to a plateau which then declines to pre-treatment values after about 8 h. A cornual nerve blockade using lignocaine virtually eliminates the escape behaviour seen during disbudding and dehorning and reduces the plasma cortisol response to dehorning for about 2 h. Thereafter there is an increase in the plasma cortisol concentration, a delayed response, which lasts for about 6 h. A cornual nerve blockade, using lignocaine combined with cauterizing the wound caused by amputation dehorning, virtually eliminates the cortisol response as does combining a lignocaine blockade with the non-steroidal anti-inflammatory drug (NSAID) ketoprofen. When xylazine is combined with a cornual nerve blockade using lignocaine before dehorning, the cortisol response is virtually eliminated for about 3 h. When this regime is used before cautery disbudding and includes a NSAID given before and after disbudding the behaviour of calves so treated suggests that pain may be alleviated for 24 h. Cautery disbudding is preferable to amputation dehorning, but for optimal pain relief xylazine sedation, local anaesthesia and a NSAID should be used with both procedures.

Nonsteroidal anti-inflammatory drugs and acetaminophen in the treatment of an acute muscle injury

BACKGROUND

Nonsteroidal anti-inflammatory drugs are frequently used to treat muscle injuries in athletes. It is not known whether the anti-inflammatory effects of these drugs are important or whether their effectiveness is a result of their central analgesic effect.

HYPOTHESIS

The effects of nonsteroidal anti-inflammatory drugs are no different than the effects of an analgesic (acetaminophen) without anti-inflammatory action in an experimental, acute muscle contusion model.

STUDY DESIGN

Controlled animal study.

METHODS

A standardized, unilateral, nonpenetrating injury was created to the tibialis anterior muscle of 96 adult male mice. Four treatment groups were used: group 1, placebo treatment; group 2, treatment with rofecoxib, a nonsteroidal anti-inflammatory drug with cyclooxygenase-2 selectivity, and treatment after the injury; group 3, rofecoxib treatment starting 24 hours before the injury; and group 4, acetaminophen treatment after the injury. The muscle and the contralateral normal muscle were evaluated at 2, 5, and 7 days after injury by grading of gait, wet weight as a measure of edema, and histologic evaluation.

RESULTS

Group 1 had significantly more gait disturbances at day 2 than all other groups (P < .05). No differences were found at days 5 and 7. Wet weights showed an increase at day 2 in group 1 (P < .01). Again, no differences were found at days 5 and 7. Histology revealed similar inflammatory changes at day 2 in all groups, with regeneration of muscle fibers at days 5 and 7.

CONCLUSIONS

The results indicate that rofecoxib as a nonsteroidal anti-inflammatory drug and acetaminophen as a non-nonsteroidal anti-inflammatory drug analgesic have similar effects. The lack of differences in wet weights and histology suggests that the anti-inflammatory effects of rofecoxib are not an important feature of its action.

CLINICAL RELEVANCE

The routine use of nonsteroidal anti-inflammatory drugs in muscle injuries may need to be critically evaluated because low-cost and low-risk analgesics may be just as effective.