Loxoprofen sodium and celecoxib for postoperative pain in patients after spinal surgery: a randomized comparative study

Population Pharmacokinetics of Loxoprofen and its alcoholic metabolites in healthy Korean men

BACKGROUND

Loxoprofen has been actively used clinically to relieve musculoskeletal pain and inflammatory symptoms. However, there are few reports on quantitative pharmacokinetic (PK) prediction tools and diversity analyzes for loxoprofen within populations.

OBJECTIVES

The aim of this study was to identify effective covariates associated with explaining inter-individual PK variability through a population pharmacokinetic (Pop-PK) modeling approach for loxoprofen, and to provide a starting point for establishing scientific dosing regimens.

METHOD

The bioequivalence PK results of loxoprofen performed on 52 healthy Korean men and the physiological and biochemical parameters derived from each individual were used as base data for the development of a Pop-PK model of loxoprofen. In order to simultaneously predict the PKs of the active form according to loxoprofen exposure, previously reported PK results of trans-alcohol loxoprofen, an active metabolite of loxoprofen, were used to expand the model.

RESULTS

The Pop-PK profiles of loxoprofen were described in terms of the basic structure of a non-sequential two absorption with 2-disposition compartment, and for inter-individual PK variations, peripheral compartment volume of distribution could be correlated with body surface area (BSA), and central compartment clearance with creatinine clearance (CrCL) and albumin levels. As a result of the model simulation, the concentrations of loxoprofen and its alcoholic metabolites in plasma significantly decreased as CrCL and albumin levels increased and decreased, respectively. On the other hand, it was confirmed that the higher the BSA, the greater the distribution of loxoprofen to the periphery, and the minimum concentrations of loxoprofen and alcoholic metabolites in plasma in steady-state increased by approximately 1.78-2 times, while the fluctuation between maximum and minimum concentrations decreased. The results suggest that patients with large BSA, impaired renal function, and high serum albumin levels may have significantly higher plasma exposure to loxoprofen and trans-alcohol loxoprofen. It was also suggested that the potential side effects in the gastrointestinal system and various tissues and the level of exposure in plasma due to long-term application of loxoprofen in this patient group could be causally explained.

CONCLUSION

This study provides a very useful starting point for a scientific precision medicine approach to loxoprofen by discovering effective covariates and establishing a quantitative model that can explain the diversity of loxoprofen PKs within the population.

CLINICAL TRIAL REGISTRATION

The clinical study protocol used in this study was thoroughly reviewed and approved by the Institutional Review Board of the Institute of Bioequivalence and Bridging Study, Chonnam National University, Gwangju, Republic of Korea. The bioequivalence study permit numbers are as follows: 041113; 10.15.2004.

Pre-emptive coinfiltration of dexamethasone palmitate emulsion with ropivacaine for postoperative pain in patients undergoing major spine surgery: a study protocol for a prospective, randomised controlled, multicentre trial

INTRODUCTION

Patients undergoing major spine surgery usually experience moderate-to-severe postoperative pain. It has been shown that dexamethasone as an adjunct to local anaesthesia (LA) infiltration presented a superior analgesic benefit compared with LA alone in various types of surgeries. However, a recent meta-analysis reported that the overall benefits of dexamethasone infiltration were marginal. Dexamethasone palmitate (DXP) emulsion is a targeted liposteroid. Compared with dexamethasone, DXP has a stronger anti-inflammatory effect, longer duration of action and fewer adverse effects. We hypothesised that the additive analgesic effects of DXP on local incisional infiltration in major spine surgery may have better postoperative analgesic effect, compared with local anaesthetic alone. However, no study has evaluated this so far. The purpose of this trial is to determine whether pre-emptive coinfiltration of DXP emulsion and ropivacaine at surgical site incision will further reduce postoperative opioid requirements and pain scores after spine surgery than that with ropivacaine alone.

METHODS AND ANALYSIS

This is a prospective, randomised, open-label, blinded endpoint, multicentre study. 124 patients scheduled for elective laminoplasty or laminectomy with no more than three levels will be randomly allocated in a 1:1 ratio into two groups: the intervention group will receive local incision site infiltration with ropivacaine plus DXP; the control group will receive infiltration with ropivacaine alone. All participants will complete a 3 months follow-up. The primary outcome will be the cumulative sufentanil consumption within 24 hours after surgery. The secondary outcomes will include further analgesia outcome assessments, steroid-related side effects and other complications, within the 3 months follow-up period.

ETHICS AND DISSEMINATION

This study protocol has been approved by the Institutional Review Board of Beijing Tiantan Hospital (KY-2019-112-02-3). All participants will provide a written informed consent. The results will be submitted for publication in a peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT05693467.

Indomethacin, a non-steroidal anti-inflammatory drug, induces skin dryness via PPARγ in mice

Cyclooxygenase (COX)-1-selective inhibitors have side effects such as itching and dryness of the skin. In this study, the degree of skin dryness and the onset mechanism of this condition were investigated by comparing the effects of three non-steroidal anti-inflammatory drugs (NSAIDs) in mice. Mice were orally administered either indomethacin, loxoprofen sodium, or celecoxib (n = 5 per group) once daily for four consecutive days, and blood samples as well as skin and jejunal tissues were isolated on day 5. In the mice treated with indomethacin, transepidermal water loss was significantly increased, and dry skin was observed. In addition, the expression of matrix metalloproteinase (MMP)-I, mast cells, CD163, CD23, CD21, histamine, and peroxisome proliferation-activated receptor (PPAR)γ in the skin and jejunum was increased, and the blood levels of interleukin-10 and immunoglobulin E were also increased. In contrast, the expression of collagen type I in the skin was decreased. These results show that indomethacin activates PPARγ in the skin and jejunum, changes the polarity of macrophages, increases the secretion of MMP-1 from mast cells, and decomposes collagen type I, leading to dry skin.

Anesthesia and Enhanced Recovery After Head and Neck Surgery

Enhanced recovery protocols have been developed from gastrointestinal, colorectal, and thoracic surgery populations. The basic tenets of head and neck enhanced recovery are: a multidisciplinary team working around the patient, preoperative carbohydrate loading, multimodal analgesia, early mobilization and oral feeding, and frequent reassessment and auditing of protocols to improve patient outcomes. The implementation of enhanced recovery protocols across surgical populations appear to decrease length of stay, reduce cost, and improve patient satisfaction without sacrificing patient quality of care or changing readmission rates. This article examines evidence-based enhanced recovery interventions and tailors them to a major head and neck surgery population.

Assessing Drug Interaction and Pharmacokinetics of Loxoprofen in Mice Treated with CYP3A Modulators

Loxoprofen (LOX) is a non-selective cyclooxygenase inhibitor that is widely used for the treatment of pain and inflammation caused by chronic and transitory conditions. Its alcoholic metabolites are formed by carbonyl reductase (CR) and they consist of trans-LOX, which is active, and cis-LOX, which is inactive. In addition, LOX can also be converted into an inactive hydroxylated metabolite (OH-LOXs) by cytochrome P450 (CYP). In a previous study, we reported that CYP3A4 is primarily responsible for the formation of OH-LOX in human liver microsomes. Although metabolism by CYP3A4 does not produce active metabolites, it can affect the conversion of LOX into trans-/cis-LOX, since CYP3A4 activity modulates the substrate LOX concentration. Although the pharmacokinetics (PK) and metabolism of LOX have been well defined, its CYP-related interactions have not been fully characterized. Therefore, we investigated the metabolism of LOX after pretreatment with dexamethasone (DEX) and ketoconazole (KTC), which induce and inhibit the activities of CYP3A, respectively. We monitored their effects on the PK parameters of LOX, cis-LOX, and trans-LOX in mice, and demonstrated that their PK parameters significantly changed in the presence of DEX or KTC pretreatment. Specifically, DEX significantly decreased the concentration of the LOX active metabolite formed by CR, which corresponded to an increased concentration of OH-LOX formed by CYP3A4. The opposite result occurred with KTC (a CYP3A inhibitor) pretreatment. Thus, we conclude that concomitant use of LOX with CYP3A modulators may lead to drug–drug interactions and result in minor to severe toxicity even though there is no direct change in the metabolic pathway that forms the LOX active metabolite.

Preemptive analgesia after lumbar spine surgery by pregabalin and celecoxib: a prospective study

Objective

To evaluate the preemptive analgesic effect of combination pregabalin with celecoxib for lumbar spine surgery.

Methods

A prospective, randomized study was conducted among 60 lumbar spine surgery patients and divided into two groups. Postoperative pain relief was achieved with intravenous patient-controlled analgesia with morphine. The preemptive analgesia group received oral pregabalin (150 mg) and celecoxib (200 mg) 2 hrs before surgery, and the control group received a placebo. Pain was assessed by visual analogue scale (VAS). Side effects and morphine consumption were monitored until 48 hrs after surgery.

Results

VAS score at rest and during movement was statistically significantly lower in the preemptive analgesia group at most time points (p<0.05). Morphine consumption was significantly lower in the preemptive analgesia group compared with control group in the 24 first hours (29.03±4.38 mg vs 24.43±4.94) and 48 hrs (52.23±9.57 mg vs 44.20±10.21 mg), p<0.05. Hemodynamics, respiratory rate, and SpO₂ were similar for both groups. The sedation score was only statistically significant at H8 time point. The incidence of nausea/vomiting in the preemptive group did not statistically differ from the control group.

Conclusion

Preoperative administration of pregabalin combined with celecoxib had a good preemptive analgesia effect and reduced intravenous morphine consumption after lumbar spine surgery. Side effects were mild and transient.

Identification of sulfonyl-loxoprofen as novel phase 2 conjugate in rat

Loxoprofen is a prodrug that exerts strong analgesic and anti-inflammatory effects through its active trans-alcohol metabolite, which is produced in the liver by carbonyl reductase. Previous metabolic studies have evaluated loxoprofen, but its sulfate and taurine conjugates have not yet been studied. We characterized the metabolomic profile of loxoprofen in rat plasma, urine, and feces using high-resolution mass spectrometry. We identified 17 metabolites of loxoprofen in the three different biological matrices, 13 of which were detected in plasma and feces and 16 in urine. Amongst these metabolites, two novel taurine conjugates (M12 and M13) and two novel acyl glucuronides (M14, M15) were identified for the first time in rats. In addition, we detected three novel sulfate conjugates (M9, M10, and M11) of loxoprofen. Further study of these metabolites of loxoprofen is essential in order to assess their potency and toxicity.

Antinociception by fluoro-loxoprofen, a novel non-steroidal anti-inflammatory drug with less ulcerogenic effects, in rat models of inflammatory pain

The use of non-steroidal anti-inflammatory drugs (NSAIDs) for the treatment of inflammatory pain is limited by gastrointestinal complications. The rapid action of NSAIDs is associated with better pain relief. Previously, we demonstrated that fluoro-loxoprofen, a novel NSAID, has less ulcerogenic potential than other NSAIDs, attributable to its gastroprotective properties. The aim of this study was to investigate and compare the effects of fluoro-loxoprofen on inflammatory pain in rats with those of other NSAIDs. Oral administration of fluoro-loxoprofen, loxoprofen, and celecoxib resulted in equivalent analgesic action against yeast-induced inflammatory pain. The antinociceptive effect of fluoro-loxoprofen was maximized within 1 h after administration, which is less time than that observed for loxoprofen (2 h) and celecoxib (3 h). We confirmed that both fluoro-loxoprofen and loxoprofen suppressed the increases in prostaglandin E₂ in inflamed paws. In addition to yeast-induced pain, fluoro-loxoprofen produced a similar effect against adjuvant-induced inflammatory pain, with faster peak analgesic effects than those observed for loxoprofen and celecoxib. Taken together, these results suggest that the analgesic effect of fluoro-loxoprofen is equivalent to that of loxoprofen and celecoxib. Moreover, the analgesic effect of fluoro-loxoprofen against inflammatory pain was more rapid than that of other NSAIDs, and this may be associated with its rapid absorption property.

Clinical research on the efficacy and safety of Bosinji for low back pain with radiculopathy caused by herniated intervertebral disc of the lumbar spine: A protocol for a multicenter, randomized, controlled equivalence trial

BACKGROUND

A lumbar herniated intervertebral disc (LHIVD) is a common problem that usually causes low back pain and radiating pain. The effectiveness of Bosinji, one of the herbal medicines used for low back pain and radiating pain in patient with LHIVD, has been reported in several studies; however, little clinical evidence is available owing to the methodological limitations in previous studies. Hence, the present study aims to establish the clinical evidence regarding the efficacy and safety of Bosinji in improving pain, function, and quality of life in LHIVD patients.

METHOD/DESIGN

This is a multicenter, open-label, randomized, controlled, and equivalence trial with 2 parallel arms. A total of 74 patients who have low back pain and radiating pain due to LHIVD will be recruited and randomly allocated to the experimental group and control group. The patients in the experimental group and control group will take 2.5 g of Bosinji granule (1.523 g of Bosinji extract) or Loxonin tablet (60 mg of loxoprofen) 3 times a day for 6 weeks. Additionally, both groups will receive the same acupuncture treatment once a week for 6 weeks as a concurrent treatment. Changes in the 100-mm visual analogue scale (VAS) for low back pain after 6 weeks from baseline will be assessed as the primary outcome. Furthermore, the 100-mm VAS for radiating pain, Oswestry disability index (ODI), Roland-Morris disability questionnaire (RMDQ), EuroQol 5 Dimensions 5 Levels (EQ-5D-5L), global perceived effect (GPE), and deficiency syndrome of kidney index (DSKI) will be used to evaluate secondary outcomes. Outcomes will be assessed at baseline and at 3, 6, and 10 weeks after screening. For the safety evaluation, laboratory examinations including complete blood count, liver function test, renal function test, blood coagulation test, inflammation test, and urine analysis will be conducted before and after taking the medications.

DISCUSSION

The results of this trial will be used to establish clinical evidence regarding the use of Bosinji with acupuncture treatment in the treatment of patients with LHIVD.

TRIAL REGISTRATION NUMBER

NCT03386149 (clinicaltrials.gov) and KCT0002848 (Clinical Research Information Service of the Republic of Korea).

Exploring the Metabolism of Loxoprofen in Liver Microsomes: The Role of Cytochrome P450 and UDP-Glucuronosyltransferase in Its Biotransformation

Loxoprofen, a propionic acid derivative, non-steroidal anti-inflammatory drug (NSAID) is a prodrug that is reduced to its active metabolite, trans-alcohol form (Trans-OH) by carbonyl reductase enzyme in the liver. Previous studies demonstrated the hydroxylation and glucuronidation of loxoprofen. However, the specific enzymes catalyzing its metabolism have yet to be identified. In the present study, we investigated metabolic enzymes, such as cytochrome P450 (CYP) and UDP-glucuronosyltransferase (UGT), which are involved in the metabolism of loxoprofen. Eight microsomal metabolites of loxoprofen were identified, including two alcohol metabolites (M1 and M2), two mono-hydroxylated metabolites (M3 and M4), and four glucuronide conjugates (M5, M6, M7, and M8). Based on the results for the formation of metabolites when incubated in dexamethasone-induced microsomes, incubation with ketoconazole, and human recombinant cDNA-expressed cytochrome P450s, we identified CYP3A4 and CYP3A5 as the major CYP isoforms involved in the hydroxylation of loxoprofen (M3 and M4). Moreover, we identified that UGT2B7 is the major UGT isoform catalyzing the glucuronidation of loxoprofen and its alcoholic metabolites. Further experimental studies should be carried out to determine the potency and toxicity of these identified metabolites of loxoprofen, in order to fully understand of mechanism of loxoprofen toxicity.