Analgesic, Antiinflammatory, and Antipyretic Effects of S(+)-Ketoprofen In Vivo

Imidazopyridine-based kinase inhibitors as potential anticancer agents: A review

Considering the fundamental role of protein kinases in the mechanism of protein phosphorylation in critical cellular processes, their dysregulation, especially in cancers, has underscored their therapeutic relevance. Imidazopyridines represent versatile scaffolds found in abundant bioactive compounds. Given their structural features, imidazopyridines have possessed pivotal potency to interact with different protein kinases, inspiring researchers to carry out numerous structural variations. In this comprehensive review, we encompass an extensive survey of the design and biological evaluations of imidazopyridine-based small molecules as potential agents targeting diverse kinases for anticancer applications. We describe the structural elements critical to inhibitory potency, elucidating their key structure-activity relationships (SAR) and mode of actions, where available. We classify these compounds into two groups: Serine/threonine and Tyrosine inhibitors. By highlighting the promising role of imidazopyridines in kinase inhibition, we aim to facilitate the design and development of more effective, targeted compounds for cancer treatment.

Pharmacokinetic/pharmacodynamic modeling of ketoprofen and flunixin at piglet castration and tail-docking

This study performed population‐pharmacokinetic/pharmacodynamic (pop‐PK/PD) modeling of ketoprofen and flunixin in piglets undergoing routine castration and tail‐docking, utilizing previously published data. Six‐day‐old male piglets (8/group) received either ketoprofen (3.0 mg/kg) or flunixin (2.2 mg/kg) intramuscularly. Two hours post‐dose, piglets were castrated and tail docked. Inhibitory indirect response models were developed utilizing plasma cortisol or interstitial fluid prostaglandin E2 (PGE2) concentration data. Plasma IC50 for ketoprofen utilizing PGE2 as a biomarker was 1.2 μg/ml, and ED50 for was 5.83 mg/kg. The ED50 calculated using cortisol was 4.36 mg/kg; however, the IC50 was high, at 2.56 μg/ml. A large degree of inter‐individual variability (124.08%) was also associated with the cortisol IC50 following ketoprofen administration. IC50 for flunixin utilizing cortisol as a biomarker was 0.06 μg/ml, and ED50 was 0.51 mg/kg. The results show that the currently marketed doses of ketoprofen (3.0 mg/kg) and flunixin (2.2 mg/kg) correspond to drug responses of 33.97% (ketoprofen‐PGE2), 40.75% (ketoprofen‐cortisol), and 81.05% (flunixin‐cortisol) of the maximal possible responses. Given this information, flunixin may be the best NSAID to use in mitigating castration and tail‐docking pain at the current label dose.

Comparison of Efficacy of Ketoprofen and Ibuprofen in Treating Pain in Patients with Rheumatoid Arthritis: A Systematic Review and Meta-Analysis

INTRODUCTION

Patients with rheumatoid arthritis (RA) or other rheumatic diseases say that pain and stiffness are symptoms affecting their quality of life. Ketoprofen and ibuprofen are the most commonly used non-steroidal anti-inflammatory drugs (NSAIDs) to reduce inflammation and manage mild-to-moderate pain. The aim of this new systematic review of the literature and meta-analysis of randomized controlled trials (RCTs) was to compare the clinical efficacy of ketoprofen and ibuprofen in patients with RA.

METHODS

The MEDLINE and EMBASE scientific databases were systematically searched from their inception to November 2020 to identify RCTs directly comparing the recommended therapeutic doses of oral ketoprofen (50-200 mg/day) with ibuprofen (600-1800 mg/day) for RA pain relief. The meta-analysis was made using the standardized mean differences (SMD) of each of the identified RCTs using a fixed effects model.

RESULTS

Four RCTs involving 456 patients met the inclusion criteria. The results of the meta-analysis showed a statistically significant difference in efficacy in favor of ketoprofen (0.33, 95% CI 0.14-0.52, p = 0.0005) at all point-estimates of the mean-weighted size effect. The heterogeneity test for the efficacy outcome (the hypothesis was χ2 = 3.57%, df = 3, p value = 0.31 and the chance of a test effect was 3.49, p = 0.0005) was not significant, and this was confirmed by a Higgins percentage of 16%. The studies included in the meta-analysis did not reveal any significant differences between the two drugs in terms of tolerability or safety.

CONCLUSIONS

The result of this meta-analysis shows that ketoprofen is more effective than ibuprofen in managing RA pain at therapeutic doses, thus supporting its use in clinical practice.

Antinociception and less gastric injury with the dexketoprofen-tapentadol combination in mice

The purpose of this study was to evaluate the antinociceptive interaction between dexketoprofen and tapentadol in three different dose ratios, as well as the ulcerogenic activity of this combination. Dose-response curves were carried out for dexketoprofen, tapentadol, and dexketoprofen-tapentadol combinations in the acetic acid-induced writhing test in mice. On the other hand, the gastric damage of all treatments was assessed after the surgical extraction of the stomachs. Intraperitoneal administration of dexketoprofen and tapentadol induced a dose-dependent antinociceptive effect, reaching a maximal effect of about 58% and 99%, respectively. Isobolographic analysis and the interaction index showed that the three proportions produced an analgesic potentiation (synergistic interaction). Interestingly, the 1:1 and 1:3 ratios of the drugs combination produced minor gastric injury in comparison with the 3:1 proportion. Our data suggest that all proportions of the dexketoprofen-tapentadol combination produced a synergistic interaction in the acetic acid-induced visceral pain model in mice with a low incidence of gastric injury.

[Evaluation of the neurotoxic effects of intrathecal administration of (S)-(+)-Ketoprofen on rat spinal cords: randomized controlled experimental study]

BACKGROUND AND OBJECTIVES

Intrathecal administration of non-steroidal anti-inflammatory drugs is more efficacious for post-operative pain management. Cyclooxygenase inhibiting non-steroidal anti-inflammatory drugs like (S)-(+)-Ketoprofen, may be effective at lower intrathecal doses than parenteral ones. Preclinical safety regarding possible neurotoxicity associated with the intrathecal (S)-(+)-Ketoprofen was not evaluated. Here we analysed the neurotoxicity of intrathecally administered (S)-(+)-Ketoprofen in rats.

METHODS

A randomized placebo-controlled experimental study was conducted. Sprague-Dawley rats (250-300g) aged 12-16 weeks were randomly divided into 2 treatments [100 and 800μg (S)-(+)-Ketoprofen] and control (sterile water) groups. Intrathecal catheters were placed via the atlantoaxial space in anesthetized rats. Pinch-toe tests, motor function evaluations and histopathological examinations of the spinal cord and nerve roots were performed at days 3, 7 and 21. Spinal cord sections were evaluated by light microscopy for the dorsal axonal funiculus vacuolation, axonal myelin loss, neuronal chromatolysis, neuritis, meningeal inflammation, adhesions, and fibrosis.

RESULTS

Rats in all the groups exhibited normal pinch-toe testing response (score=0) and normal gait at each observed time (motor function evaluation score=1). Neurotoxicity was higher with treatments on days 3 and 7 than that on day 21 (2, 3, 0, p=0.044; 2, 5, 0, p=0.029, respectively). On day 7, the total scores reflecting neuronal damage were higher in the 800μg group than those in the 100μg and Control Groups (5, 3, 0, p=0.048, respectively).

CONCLUSION

Intrathecal (S)-(+)-Ketoprofen caused dose-dependent neurohistopathological changes in rats on days 3 and 7 after injection, suggesting that (S)-(+)-Ketoprofen should not be intrathecally administered.

Evaluation of the neurotoxic effects of intrathecal administration of (S)-(+)-Ketoprofen on rat spinal cords: randomized controlled experimental study

Background and objectives

Intrathecal administration of non-steroidal anti-inflammatory drugs is more efficacious for post-operative pain management. Cyclooxygenase inhibiting non-steroidal anti-inflammatory drugs like (S)-(+)-Ketoprofen, may be effective at lower intrathecal doses than parenteral ones. Preclinical safety regarding possible neurotoxicity associated with the intrathecal (S)-(+)-Ketoprofen was not evaluated. Here we analysed the neurotoxicity of intrathecally administered (S)-(+)-Ketoprofen in rats.

Methods

A randomized placebo-controlled experimental study was conducted. Sprague-Dawley rats (250–300 g) aged 12–16 weeks were randomly divided into 2 treatments [100 and 800 μg (S)-(+)-Ketoprofen] and control (sterile water) groups. Intrathecal catheters were placed via the atlantoaxial space in anesthetized rats. Pinch-toe tests, motor function evaluations and histopathological examinations of the spinal cord and nerve roots were performed at days 3, 7 and 21. Spinal cord sections were evaluated by light microscopy for the dorsal axonal funiculus vacuolation, axonal myelin loss, neuronal chromatolysis, neuritis, meningeal inflammation, adhesions, and fibrosis.

Results

Rats in all the groups exhibited normal pinch-toe testing response (score = 0) and normal gait at each observed time (motor function evaluation score = 1). Neurotoxicity was higher with treatments on days 3 and 7 than that on day 21 (2, 3, 0, p = 0.044; 2, 5, 0, p = 0.029, respectively). On day 7, the total scores reflecting neuronal damage were higher in the 800 μg group than those in the 100 μg and Control Groups (5, 3, 0, p = 0.048, respectively).

Conclusion

Intrathecal (S)-(+)-Ketoprofen caused dose-dependent neurohistopathological changes in rats on days 3 and 7 after injection, suggesting that (S)-(+)-Ketoprofen should not be intrathecally administered.

Analgesic effect of S (+)-flurbiprofen plaster in a rat model of knee arthritis: analysis of gait and synovial fluid prostaglandin E2 levels

Objectives

We developed S (+)‐flurbiprofen plaster (SFPP), a novel NSAID patch containing S (+)‐flurbiprofen (SFP), a potent cyclooxygenase (COX) inhibitor. The purpose of this study was to assess efficacy of SFPP by analysing its effect on the gait disturbance and measuring the prostaglandin E₂ (PGE₂) production in synovial fluid in a rat model of knee arthritis.

Methods

Knee inflammation was induced in rats by intra‐articular injection of a yeast suspension. Subsequently, an NSAID patch containing SFP, ketoprofen or loxoprofen was applied over the affected knee. Gait was assessed at 2, 4 and 6 h after application of the patch. The PGE₂ concentration in the synovial fluid was measured after the gait assessment.

Key findings

Application of SFPP (0.125, 0.25, 0.5 or 1 mg/sheet) was followed by a decrease in the visual gait score at all the doses examined. In the case of the other two NSAID patches, only the ketoprofen patch (1 or 2 mg/sheet) and loxoprofen patch (5 mg/sheet) produced a decrease in the visual gait score. All of the NSAID patches decreased the PGE₂ production in the synovial fluid.

Conclusions

These results suggest the potential usefulness of SFPP as an analgesic patch in patients with inflammatory joint pain.

Pharmacokinetics and Pharmacodynamics of (S)-Ketoprofen Co-Administered with Caffeine: A Preclinical Study in Arthritic Rats

The purpose of the present study was to determine whether caffeine modifies the pharmacokinetics and pharmacodynamics of (S)-ketoprofen following oral administration in a gout-type pain model. 3.2 mg/kg of (S)-ketoprofen alone and combined with 17.8 mg/kg of caffeine were administered to Wistar rats and plasma levels were determined between 0.5 and 24.0 h. Additionally, antinociception was evaluated based on the protocol of the PIFIR (pain-induced functional impairment in the rat) model before blood sampling between 0.5 and 4.0 h. Significant differences in C_max, AUC_0-24, and AUC_0-∞ values were observed with caffeine administration (p < 0.05). Also, significant differences in E_max, T_max, and AUC_0-4 values were determined when comparing the treatments with and without caffeine (p < 0.05). By relating the pharmacokinetic and pharmacodynamic data, a counter-clockwise hysteresis loop was observed regardless of the administration of caffeine. When the relationship between AUCe and AUCp was fitted to the sigmoidal E_max model, a satisfactory correlation was found (R² > 0.99) as well as significant differences in E_max and EC₅₀ values (p < 0.05). With caffeine, E_max and EC₅₀ values changed by 489.5% and 695.4%, respectively. The combination studied represents a convenient alternative for the treatment of pain when considering the advantages offered by using drugs with different mechanisms of action.

Cyclooxygenase enzyme activity does not impair respiratory motor plasticity after one night of intermittent hypoxia

Although inflammation is prevalent in many clinical disorders challenging breathing, we are only beginning to understand the impact of inflammation on neural mechanisms of respiratory control. We recently demonstrated one form of respiratory motor plasticity is extremely sensitive to even mild inflammation induced by a single night (8 h) of intermittent hypoxia (IH-1), mimicking aspects of obstructive sleep apnea. Specifically, phrenic long-term facilitation (pLTF) following moderate acute intermittent hypoxia (AIH) is abolished by IH-1, but restored by high doses of the non-steroidal anti-inflammatory drug, ketoprofen. Since a major target of ketoprofen is cyclooxygenase (COX) enzymes, we tested the involvement of COX in IH-1 suppression of pLTF using the selective COX inhibitor NS-398. Systemic COX inhibition (3 mg/kg, i.p., 3 h before AIH) had no effect on pLTF in normoxia treated rats (76 ± 40% change from baseline, n = 6), and did not restore pLTF in IH-1 treated rats (-9 ± 7% baseline, n = 6). Similarly, spinal COX inhibition (27 mM, 12 μl, i.t.) had no effect on pLTF in normoxic rats (76 ± 34% baseline, n = 7), and did not significantly restore pLTF after IH-1 (37 ± 18% baseline, n = 7). COX-2 protein is expressed in identified phrenic motor neurons of both normoxia and IH-1 exposed rats, but immunolabeling was minimal in surrounding microglia; IH-1 had no discernable effect on COX-2 immunoreactivity. We conclude that the inflammatory impairment of pLTF by IH-1 is independent of COX enzyme activity or upregulated COX-2 expression.

Comparison of selective and non selective cyclo-oxygenase 2 inhibitors in experimental colitis exacerbation: role of leukotriene B4 and superoxide dismutase

CONTEXT

Nonsteroidal anti-inflammatory drugs are considered one of the most important causes of reactivation of inflammatory bowel disease. With regard to selective cyclo-oxygenase 2 inhibitors, the results are controversial in experimental colitis as well as in human studies.

OBJECTIVES

The aim this study is to compare nonsteroidal anti-inflammatory drugs effects, selective and non selective cyclo-oxygenase 2 inhibitors, in experimental colitis and contribute to the understanding of the mechanisms which nonsteroidal anti-inflammatory drugs provoke colitis exacerbation.

METHODS

Six groups of rats: without colitis, with colitis, and colitis treated with celecoxib, ketoprofen, indometacin or diclofenac. Survival rates, hemoglobin, plasmatic albumin, colonic tissue of interleukin-1ß, interleukin-6, tumor necrosis factor alpha, prostaglandin E2, catalase, superoxide dismutase, thiobarbituric acid-reactive substances, chemiluminescence induced by tert-butil hydroperoxides, and tissue and plasmatic leukotriene B4 were determined.

RESULTS

The groups treated with diclofenac or indometacin presented lower survival rates, hemoglobin and albumin, higher tissue and plasmatic leukotriene B4 and tissue superoxide dismutase than the group treated with celecoxib. Ketoprofen presented an intermediary behavior between diclofenac/indometacin and celecoxib, concerning to survival rate and albumin. The groups without colitis, with colitis and with colitis treated with celecoxib showed leukotriene B4 and superoxide dismutase lower levels than the groups treated with nonselective cyclo-oxygenase 2 inhibitors.

CONCLUSIONS

Diclofenac and indometacin presented the highest degree of induced colitis exacerbation with nonsteroidal anti-inflammatory drugs, celecoxib did not show colitis exacerbation, and ketoprofen presented an intermediary behavior between diclofenac/indometacin and celecoxib. These results suggest that leukotriene B4 and superoxide dismutase can be involved in the exacerbation of experimental colitis by nonselective nonsteroidal anti-inflammatory drugs.

Mechanical properties and dual drug delivery application of poly(lactic-co-glycolic acid) scaffolds fabricated with a poly(β-amino ester) porogen

Polymeric scaffolds that are biocompatible and biodegradable are widely used for tissue engineering applications. Scaffolds can be further enhanced by enabling the release of one or more drugs to stimulate regeneration or for the treatment of a specific disease or condition. In this study, poly(lactic-co-glycolic acid) (PLGA) microspheres were mixed with poly(β-amino ester) (PBAE) particles to create novel hybrid scaffolds capable of dual release of drug and growth factor. Fast-degrading PBAE particles loaded with the drug ketoprofen acted as porogens that provided a rapid 12h release. The PLGA microspheres were loaded with a growth factor, bone morphogenetic protein 2, and fused together around the porogens to create a slow-degrading matrix that provided sustained release lasting 70days. Drug release was further tailored by varying the amount of porogen added to the scaffold. Bioactivity measurements demonstrated that the scaffold fabrication technique did not damage the drug or protein. The compressive modulus was affected by the amount of porogen added, extending from 50 to 111MPa for loadings from 60 to 40% PBAE, and after 5days of degradation, it decreased to 0.6 to 1.1kPa when the porogen was gone. PLGA containing a quick-degrading porogen can be used to release two drugs while developing a porous microarchitecture for cell ingrowth with in a matrix capable of maintaining a compressive modulus applicable for soft tissue implants.

Differential modulation in binding of ketoprofen to bovine serum albumin in the presence and absence of surfactants: spectroscopic and calorimetric insights

Surfactants have long been implicated in the unique static and dynamic effect on the structure and function of serum albumins. However, there is very little information on the mode of interactions of drugs to serum albumins in presence of surfactants. The importance of such studies lay in the fact that apart from binding to serum albumins, surfactants are known to radically influence the solvents' micro environment and protein structure. Thus, we have studied the binding of the racemic form of ketoprofen with bovine serum albumin at pH 7.4 in the presence and absence of hexadecyl trimethyl ammonium bromide, sodium dodecyl sulfate, Triton X-100, and NaCl. The structural studies of ketoprofen with bovine serum albumin as investigated by circular dichroism spectroscopy revealed a significant stabilization of bovine serum albumin. However, the combined presence of the surfactants, NaCl and ketoprofen, demonstrated an extremely erratic behavior in terms of stabilization. Further the values of Stern-Volmer and dynamic quenching constant suggested the binding site of ketoprofen to be scattered in the region of domain I B and II A, close to Trp 134. The results of differential scanning calorimetry revealed that the binding of ketoprofen to bovine serum albumin leads to its temperature-dependent separation into two units. The binding parameters of bovine serum albumin obtained from isothermal titration calorimetry in the combined presence of ketoprofen and surfactants/NaCl correlate well with the differential scanning calorimetry studies further confirming the localization of ketoprofen in domain I B and II A. In the combined presence of surfactants, NaCl and ketoprofen, the binding of ketoprofen to bovine serum albumin exhibited altered binding parameters far different from the binding of ketoprofen alone. Overall, the experimental findings strongly indicated positive as well as negative modulation in the binding of ketoprofen to bovine serum albumin in the presence of ligands.

Comparative assessment of effectiveness of ketoprofen and ketoprofen/beta-cyclodextrin complex in two experimental models of inflammation in rats

Oral administration of non-steroidal anti-inflammatory drugs (NSAIDs) can lead to adverse effects such as gastrointestinal distress. The complexation of different groups of active substances with β-cyclodextrin (β-CD) has drawn considerable interest over recent years. The purpose of this study was to analyze the ketoprofen/β-cyclodextrin (K/β-CD) conjugate complex as well as to assess its anti-inflammatory effect after oral administration (doses of 30 mg/m(2) and 15 mg/m(2) of body surface), compared with ketoprofen. The studies were done on two models of experimentally-induced acute inflammation in rats (n = 48, 6/group), by means of intraplantar administration of a 10% aqueous kaolin suspension and intraperitoneal administration of a 1% sodium thioglycolate solution. The dynamics of the acute inflammatory process and the anti-inflammatory effects were monitored using plethysmometric determinations after 3, 6, 9, 12, 24 and 48 h (plantar inflammation), and the absorbance of the exudates (spectrophotometrically read) and nucleated cell counts after 24 h (peritoneal inflammation). The coupling of ketoprofen with β-CD resulted in increased solubility (100% in 60 min) of the newly-formed product, which further resulted in a higher bioavailability compared with ketoprofen (<40% in 120 min). In both models of experimentally-induced inflammation, the K/β-CD complex had a higher anti-inflammatory activity than ketoprofen.

Ilioinguinal-iliohypogastric nerve block with intravenous dexketoprofen improves postoperative analgesia in abdominal hysterectomies

BACKGROUND AND OBJECTIVE

In this study, our aim was to evaluate the effects of intravenous dexketoprofen trometamol with ilioinguinal and iliohypogastric nerve block on analgesic quality and morphine consumption after total abdominal hysterectomy operations.

METHODS

We conducted this randomized controlled clinical study on 61 patients. The study was conducted in the operation room, post-anesthesia care unit, and inpatient clinic. We randomly grouped the 61 patients into control group (group C), block group (group B) and dexketoprofen-block group (group DB). Before the skin incision performed after anesthesia induction, we performed ilioinguinal iliohypogastric block (group C given saline and group P and DB given levobupivacaine). In contrast to group C and B, group DB was given dexketoprofen. We administered morphine analgesia to all patients by patient-controlled analgesia (PCA) during the postoperative 24 hours. We recorded Visual Analogue Scale (VAS), satisfaction scores, morphine consumption and side effects during postoperative 24 hours.

RESULTS

We found the DB group's VAS scores to be lower than the control group and block group's (p < 0.05) values at postoperative 1(st), 2(nd), 6(th) and 12(th) hours. VAS scores of group C were higher than of group B at postoperative first 2 hours. Time to first PCA demand was longer, morphine consumption values were lower and satisfaction scores were higher in group DB than in the other two groups (p < 0.05).

CONCLUSIONS

Ilioinguinal-iliohypogastric nerve block with IV dexketoprofen increases patient satisfaction by decreasing opioid consumption, increasing patient satisfaction, which suggests that dexketoprofen trometamol is an effective non-steroidal anti-inflammatory analgesic in postoperative analgesia.

Systemic LPS induces spinal inflammatory gene expression and impairs phrenic long-term facilitation following acute intermittent hypoxia

Although systemic inflammation occurs in most pathological conditions that challenge the neural control of breathing, little is known concerning the impact of inflammation on respiratory motor plasticity. Here, we tested the hypothesis that low-grade systemic inflammation induced by lipopolysaccharide (LPS, 100 μg/kg ip; 3 and 24 h postinjection) elicits spinal inflammatory gene expression and attenuates a form of spinal, respiratory motor plasticity: phrenic long-term facilitation (pLTF) induced by acute intermittent hypoxia (AIH; 3, 5 min hypoxic episodes, 5 min intervals). pLTF was abolished 3 h (vehicle control: 67.1 ± 27.9% baseline; LPS: 3.7 ± 4.2%) and 24 h post-LPS injection (vehicle: 58.3 ± 17.1% baseline; LPS: 3.5 ± 4.3%). Pretreatment with the nonsteroidal anti-inflammatory drug ketoprofen (12.5 mg/kg ip) restored pLTF 24 h post-LPS (55.1 ± 12.3%). LPS increased inflammatory gene expression in the spleen and cervical spinal cord (homogenates and isolated microglia) 3 h postinjection; however, all molecules assessed had returned to baseline by 24 h postinjection. At 3 h post-LPS, cervical spinal iNOS and COX-2 mRNA were differentially increased in microglia and homogenates, suggesting differential contributions from spinal cells. Thus LPS-induced systemic inflammation impairs AIH-induced pLTF, even after measured inflammatory genes returned to normal. Since ketoprofen restores pLTF even without detectable inflammatory gene expression, "downstream" inflammatory molecules most likely impair pLTF. These findings have important implications for many disease states where acute systemic inflammation may undermine the capacity for compensatory respiratory plasticity.

The effects of dexketoprofen on duration of analgesia to a thermal stimulus when compared with a systemic control in a rat sciatic nerve block with levobupivacaine

This study was designed to investigate whether dexketoprofen added to perineuraly or subcutaneously alters the effects of levobupivacaine in a rat model of sciatic nerve blockade. Thirty-six rats received unilateral sciatic nerve blocks along with a subcutaneous injection by a blinded investigator assigned at random. Combinations were as follows: Group 1 (sham) perineural and subcutaneous saline; Group 2, perineural levobupivacaine alone and subcutaneous saline; Group 3, perineural levobupivacaine plus dexketoprofen and subcutaneous saline; Group 4, perineural levobupivacaine and subcutaneous dexketoprofen; Group 5, perineural dexketoprofen and subcutaneous saline; and Group 6, perineural saline and subcutaneous dexketoprofen. The levobupivacaine concentration was fixed at 0.05%, and the dose of dexketoprofen was 1 mg kg(-1) . Sensory analgesia was assessed by paw withdrawal latency to a thermal stimulus every 30 min. The unblocked paw served as the control for the assessment of systemic, centrally mediated analgesia. Perineural and subcutaneous dexketoprofen coadministered with perineural levobupivacaine did not enhance the duration of sensory blockade when compared with levobupivacaine alone. There were significant differences between the operative and control paws for time points 30-90 min in the perineural levobupivacaine alone, levobupivacaine + dexketoprofen and subcutaneous dexketoprofen added levobupivacaine group. Significant differences were not determined between the levobupivacaine alone group and dexketoprofen added groups in operative paw. The effects of dexketoprofen are unknown for perineural administration. There is no significant difference between the analgesic effects of peripheral nerve blocks using levobupivacaine alone and plus subcutaneous or perineural dexketoprofen.

Enantioselective pharmacokinetics of ketoprofen in piglets: the significance of neonatal age

Following intravenous dose of 6mg/kg racemic ketoprofen, the chiral pharmacokinetics of ketoprofen was investigated in eight piglets aged 6 and 21days old. S-ketoprofen predominated over R-ketoprofen in plasma of the piglets in both age groups. The volumes of distribution of S-ketoprofen for the 6- and 21-day-old piglets were 241.7 (211.3-276.5) mL/kg and 155.0 (138.7-173.1) mL/kg, respectively, while the corresponding parameters for R-ketoprofen were 289.2 (250.3-334.2) mL/kg and 193.0 (168.7-220.8) mL/kg. The clearances of R-ketoprofen [948.4 (768.0-1171.2) mL/h/kg and 425 (319.1-566.0) mL/h/kg for the 6- and 21-day-old piglets, respectively] were significantly higher compared to the clearances of S-ketoprofen [57.3 (46.6-70.4) mL/h/kg and 33.8 (27.0-42.2) mL/h/kg for 6- and 21-day-old piglets, respectively]. The elimination half-life of S-ketoprofen was 3.4h for both age groups, while the elimination half-life of R-ketoprofen was 0.2h for the 6-day-old and 0.4h for the 21-day-old piglets. The clearances of both R- and S-ketoprofen were significantly higher in the 6-day-old piglets compared to when they were 21 days old. Furthermore, the volumes of distribution were larger in the youngest age group.

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.

Evidence for a central mechanism of action of S-(+)-ketoprofen

It has been observed that some non-steroidal anti-inflammatory drugs (NSAIDs) may act through several mechanisms, in addition to central inhibition of prostaglandin synthesis. These other mechanisms include the L-arginine-nitric oxide (L-arginine-NO) pathway, as well as endogenous opiate and serotonergic mechanisms. Some of these mechanisms can explain the efficacy of NSAIDs in chronic pain conditions such as rheumatoid arthritis. The present study was designed to elucidate the involvement of the above pathways/mechanisms in the antinociceptive effect of S-(+)-ketoprofen at supraspinal and spinal levels. S-(+)-ketoprofen induced dose-dependent antinociception in the pain-induced functional impairment model in the rat. The antinociceptive effect of S-(+)-ketoprofen was not altered by i.t. or intracerebroventricula (i.c.v.) pre-treatment with L-arginine (29.6 microg/site) and L-nitro-arginine-monomethylester (L-NAME) (21.1 microg/site) and neither was the effect of S-(+)-ketoprofen modified by the opiate antagonist, naloxone (1 mg/kg, s.c.). In marked contrast, both i.c.v. administration of the 5-hydroxytryptamine (5-HT)(1)/5-HT(2)/5-HT(7) receptor antagonist, methiothepin (1.5 microg/site), and i.t. administration of the 5-HT(3)/5-HT(4) receptor antagonist, tropisetron (0.9 microg/site), significantly inhibited the S-(+)-ketoprofen-induced antinociceptive effect. These data suggest that the antinociceptive response to S-(+)-ketoprofen involves serotoninergic mechanisms via both supraspinal 5-HT(1)/5-HT(2)/5-HT(7) receptors and 5-HT(3) receptors located at spinal level. A role of the L-arginine-NO and opiate systems in S-(+)-ketoprofen-induced antinociception in the pain-induced functional impairment model in the rat model seems unlikely.

Antinociception and the new COX inhibitors: research approaches and clinical perspectives

New generations of cyclooxygenase (COX) inhibitors are more potent and efficacious than their traditional parent compounds. They are also safer than the classic non-steroidal anti-inflammatory drugs (NSAIDs) and are starting to be used not only for low to moderate intensity pain, but also for high intensity pain. Three different strategies have been followed to improve the pharmacological profile of COX inhibitors: 1. Development of COX-2 selective inhibitors. This is based on the initial hypothesis that considered COX-2 as the enzyme responsible for the generation of prostaglandins only in inflammation, and, therefore, uniquely responsible for inflammation, pain and fever. Initial expectations gave rise to controversial results, still under discussion. The second generation of these compounds is being developed and should contribute to clarifying both their efficacy and the specific functions of the COX enzymes. 2. Modified non-selective COX inhibitors. Molecules like nitro-NSAIDs or tromethamine salt derivatives have been synthesized considering that both COX-1 and COX-2 are responsible for the synthesis of prostaglandins involved either in homeostatic functions or inflammation. Nitroaspirin, nitroparacetamol or dexketoprofen trometamol are some examples of molecules that are already showing an important clinical efficacy. The modifications performed in their structures seem to lower the unwanted side effects as well as to enhance their analgesic efficacy. 3. Combined therapy of classic NSAIDs with other drugs. This strategy looks for improvements in the incidence of adverse effects or to take advantage of the synergistic enhancement of their therapeutic effects. Some of the molecules resulting from these strategies are very valuable as therapeutic agents and open a wide range of possibilities in the treatment of high intensity pain, including neuropathic pain, and opiate sparing therapy.

Comparative study of analgesic efficacy and morphine-sparing effect of intramuscular dexketoprofen trometamol with ketoprofen or placebo after major orthopaedic surgery

AIMS

Multimodal analgesia is thought to produce balanced and effective postoperative pain control. A combined therapy with nonsteroidal anti-inflammatory drugs (NSAIDs) and opiates could result in synergistic analgesia by acting through different mechanisms. Currently there are very few parenterally administered NSAIDs suitable for the immediate postoperative period. Therefore, this study was undertaken to assess the analgesic efficacy, relative potency, and safety of parenteral dexketoprofen trometamol following major orthopaedic surgery.

METHODS

One hundred and seventy-two patients elected for prosthetic surgery, were randomized to receive two intramuscular injections (12 hourly) of either dexketoprofen 50 mg, ketoprofen 100 mg or placebo in a double-blind fashion. Postoperatively, the patient's pain was stabilized, then they were connected to a patient- controlled analgesia system (PCA) of morphine for 24 h (1 mg with 5 min lockout).

RESULTS

The mean cumulative amount of morphine (CAM) used was of 39 mg in the dexketoprofen group and 45 mg in the ketoprofen group vs 64 mg in the placebo group. (Reduction in morphine use was approximately one-third between the active compounds compared with placebo (adjusted mean difference of -25 mg between dexketoprofen and placebo and -23 mg between ketoprofen and placebo. These differences were statistically significant: P </= 0.0003; 95% CI -35, -14. Pain-intensity scores were consistently lower with the active compounds, the lowest corresponded to the dexketoprofen-treated patients. Regarding sedation, there were statistically significant differences between the two active compounds and placebo only at the 2nd and 13th hours. Wound bleeding was specifically measured with no statistically significant differences found between all the groups.

CONCLUSIONS

Intramuscular administration of dexketoprofen trometamol 50 mg has good analgesic efficacy both in terms of opioid-sparing effect and control of pain after major orthopaedic surgery.

Comparison of dexketoprofen trometamol and dipyrone in the treatment of renal colic

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAIDs) have been widely used for pain relief in patients with renal colic. Dexketoprofen trometamol is an NSAID that has demonstrated good analgesic efficacy and a good safety profile after oral administration in different models of acute and chronic pain.

OBJECTIVE

To assess the analgesic efficacy and safety of single intramuscular doses of dexketoprofen trometamol (25 and 50mg) compared with dipyrone (2g) in moderate to severe pain due to renal colic.

STUDY DESIGN

Multicentre, randomised, double-blind, parallel-group study.

PATIENTS

PATIENTS of both sexes aged 18-70 years with a diagnosis of renal colic were eligible for randomisation if they presented with at least moderate pain as assessed by visual analogue scale (VAS) scoring ≥40mm on a scale of 100mm immediately before study drug administration.

METHODS

Assessment of analgesic efficacy was done using standard pain intensity and pain relief scales. Total scores from baseline to 6 hours after study drug administration were calculated for the sum of pain intensity differences relative to baseline (SPID), sum of analogue pain intensity differences relative to baseline (SAPID) and total pain relief scores (TOTPAR) as primary efficacy endpoints. Secondary efficacy and safety variables were also analysed.

RESULTS

A total of 333 patients (dexketoprofen 25mg, n = 112; dexketoprofen 50mg, n = 113; dipyrone 2g, n = 108) were included in the study. No significant differences were found between the treatment groups with regard to SPID (p = 0.797), SAPID (p = 0.852) and TOTPAR (p = 0.716). The time-effect course for pain intensity differences and pain relief showed significantly (p < 0.05) higher values for both doses of dexketoprofen trometamol compared with dipyrone during the first hour after treatment administration. More than 90% of the patients in all three groups achieved pain relief of at least 50% as compared with baseline. Similarly, over 70% of the patients in all three groups considered the received treatment as excellent or good in the overall assessment of efficacy at the end of the study. No dose-effect relationship was observed in this pain model between both doses of dexketoprofen trometamol. All three treatments were well tolerated, showing mostly mild to moderate adverse events.

CONCLUSION

Dexketoprofen trometamol is a good analgesic for the treatment of moderate to severe pain due to renal colic, with a good safety profile and an efficacy comparable to that of dipyrone. The significantly greater effect of dexketoprofen trometamol early after administration suggests a faster onset of action, which can be of paramount importance in this condition.

Effect of perioperative administration of dexketoprofen on opioid requirements and inflammatory response following elective hip arthroplasty

BACKGROUND

In this double-blind, randomized, placebo-controlled trial, the safety and analgesic efficacy of perioperative dexketoprofen were evaluated.

METHODS

Thirty ASA I or II patients undergoing elective hip arthroplasty were randomized to one of two groups. One group (D) received dexketoprofen 25 mg tds for 24 h before and 48 h after surgery; the second group (P) received placebo tablets at equivalent times. Hyperbaric 0.5% bupivacaine (17.5 mg if greater than 70 kg and 15 mg if less than 70 kg) and preservative-free morphine (0.6 mg) were administered intrathecally. Postoperatively, PCA was provided (bolus morphine sulphate 1 mg; lockout 5 min; no continuous infusion).

RESULTS

The two groups were similar in terms of age, gender, weight, height, ASA class, duration of operation, and level of sensory block on arrival to the recovery room. Groups were also similar in terms of blood loss, transfusion requirements, ventilatory frequency, and haemodynamic variables. According to visual analogue pain scores patients in group D experienced less pain at 15 h (P=0.02) postoperatively. Cumulative morphine consumption was also less in group D compared with group P at 6 (0.06 (0.2) vs 0.85 (1.4) mg, P=0.04) and 48 h postoperatively (10.1 (8) vs 26.2 (20) mg, P<0.01). Plasma interleukin 6 concentrations increased postoperatively to a significantly lesser extent in group D than in group P (P=0.02). Nausea and vomiting were less (P<0.01) in group D compared with group P at 18 h postoperatively. Sedation scores were less (P=0.03) in group D.

CONCLUSIONS

Perioperative administration of dexketoprofen 25 mg 8 hourly markedly improves analgesia and decreases opioid requirements (and associated adverse effects) following hip arthroplasty. It appears that this regimen decreases the postoperative pro-inflammatory response.

Differential effects of spinal (R)-ketoprofen and (S)-ketoprofen against signs of neuropathic pain and tonic nociception: evidence for a novel mechanism of action of (R)-ketoprofen against tactile allodynia

The spinal activity of racemic ketoprofen and its enantiomers in models of neuropathic and tonic pain was explored in rats. Tactile allodynia and thermal hyperalgesia were induced by tight ligation of the L(5)/L(6) spinal nerves. Tonic pain was modeled by the formalin-induced flinch response. The spinal injection of (S)-ketoprofen alone or of morphine alone did not produce antiallodynic activity. A 1:1 combination of these drugs produced a robust dose-dependent antiallodynic action, consistent with previous observations where (S)-ketorolac combined with morphine also produced antiallodynia. (R)-ketoprofen given alone spinally produced a dose-dependent antiallodynia, but its activity was not augmented by spinal morphine. Conversely, (S)-ketoprofen, but not (R)-ketoprofen, blocked the second phase of the formalin-induced flinch response; neither enantiomer significantly blocked phase one of the formalin response. Again, (S)-, but not (R)-ketoprofen, interacted synergistically with spinal morphine in suppressing the phase II formalin response. These results are consistent with a spinal COX inhibitory action of (S)-ketoprofen. These results also point to a novel, as yet undefined, mechanism of action of (R)-ketoprofen against signs of neuropathic pain that does not appear to involve COX inhibition. The ability to modulate tactile allodynia is of special interest as this represents an aspect of clinical neuropathic pain that is very difficult to treat adequately.