Meloxicam, 15 mg/day, spares platelet function in healthy volunteers

Disconnect between COX-2 selective inhibition and cardiovascular risk in preclinical models

INTRODUCTION

Secondary pharmacology profiling is routinely applied in pharmaceutical drug discovery to investigate the pharmaceutical effects of a drug at molecular targets distinct from (off-target) the intended therapeutic molecular target (on-target). Data from a randomized, placebo-controlled clinical trial, the APPROVe (Adenomatous Polyp Prevention on VIOXX, rofecoxib) trial, raised significant concerns about COX-2 inhibition as a primary or secondary target, shaping the screening and decision-making processes of some pharmaceutical companies. COX-2 is often included in off-target screens due to cardiovascular (CV) safety concerns about secondary interactions with this target. Several potential mechanisms of COX-2-mediated myocardial infarctions have been considered including, effects on platelet stickiness/aggregation, vasal tone and blood pressure, and endothelial cell activation. In the present study, we focused on each of these mechanisms as potential effects of COX-2 inhibitors, to find evidence of mechanism using various in vitro and in vivo preclinical models.

METHODS

Compounds tested in the study, with a range of COX-2 selectivity, included rofecoxib, celecoxib, etodolac, and meloxicam. Compounds were screened for inhibition of COX-2 vs COX-1 enzymatic activity, ex vivo platelet aggregation (using whole blood from multiple species), ex vivo canine femoral vascular ring model, in vitro human endothelial cell activation (with and without COX-2 induction), and in vivo cardiovascular assessment (anesthetized dog).

RESULTS

The COX-2 binding assessment generally confirmed the COX-2 selectivity previously reported. COX-2 inhibitors did not have effects on platelet function (spontaneous aggregation or inhibition of aggregation), cardiovascular parameters (mean arterial pressure, heart rate, and left ventricular contractility), or endothelial cell activation. However, rofecoxib uniquely produced an endothelial mediated constriction response in canine femoral arteries.

CONCLUSION

Our data suggest that rofecoxib-related cardiovascular events in humans are not predicted by COX-2 potency or selectivity. In addition, the vascular ring model suggested possible adverse cardiovascular effects by COX-2 inhibitors, although these effects were not seen in vivo studies. These results may also suggest that COX-2 inhibition alone is not responsible for rofecoxib-mediated adverse cardiovascular outcomes.

Platelet Function: Meloxicam Intravenous in Whole Blood Samples From Healthy Volunteers

Nonsteroidal anti‐inflammatory drugs (NSAIDs) are effective treatments for pain but may induce bleeding events due to platelet dysfunction associated with inhibition of cyclooxygenase (COX)‐1 impairing thromboxane production. An intravenous nanocrystal formulation of meloxicam, a COX‐2 preferential nonsteroidal anti‐inflammatory drug, is under development for the treatment of moderate to severe pain. This single‐center ex vivo study evaluated the effect of meloxicam intravenous and ketorolac on platelet function in whole blood samples from healthy volunteers. Each whole blood sample was aliquoted to allow analysis using a platelet function analyzer under negative control (untreated), positive control (2 therapeutic ketorolac concentrations), and meloxicam intravenous (1 therapeutic, 3 supratherapeutic concentrations) using both collagen with epinephrine and collagen with adenosine diphosphate reagent cartridges. The platelet function analyzer determines closure time by simulating platelet adhesion and aggregation following vascular injury. The final analysis set included data from 8 subjects. The collagen with adenosine diphosphate analysis (sensitive to thrombocytopathies) showed no significant differences in closure time for meloxicam‐ or ketorolac‐treated samples and untreated control. The collagen with epinephrine analysis (sensitive to aspirin‐induced platelet abnormalities) produced no significant difference in closure time between any meloxicam concentration and untreated control. Ketorolac was associated with significantly longer closure times vs untreated control at both the 2.5‐ and 5‐µg/mL concentrations (P = .003 and .0257, respectively) and vs meloxicam at several concentrations. Similar results were observed when all analyzed samples were included. Meloxicam intravenous had no significant effect on closure times at therapeutic or supratherapeutic concentrations in this ex vivo study.

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.

Assessment of common nonsteroidal anti-inflammatory medications by whole blood aggregometry: a clinical evaluation for the perioperative setting

OBJECTIVE

To help define the perioperative risk related to commonly used non-aspirin NSAIDs with whole blood platelet aggregometry.

METHODS

Twelve healthy volunteers were recruited. Two cyclooxygenase (COX)-1 inhibitors (ibuprofen and naproxen) and two COX-2 inhibitors (meloxicam and celecoxib) were administered, and daily whole blood platelet aggregometry studies were obtained until studies showed no platelet inhibition. Aspirin was studied at the conclusion of the study.

RESULTS

Ibuprofen had no inhibitory effect on platelet aggregation in all women and no inhibitory effect in 83% of men at 24 hours. All platelet function had returned to normal at 48 hours. The inhibitory effect of naproxen on platelets was absent at 48 hours in 83% of the women and 50% of men. By 72 hours all platelet studies had returned to normal. Meloxicam and celecoxib did not cause any overall inhibitory effect on platelet aggregation.

CONCLUSIONS

Ibuprofen and naproxen have a mild inhibitory effect on platelet aggregation compared with aspirin and this effect is undetectable by 48 hours and 72 hours, respectively. Meloxicam and celecoxib show essentially no inhibitory effect on platelet aggregation. These findings suggest that there is little bleeding risk related to platelet aggregation at 24 hours in patients who take COX-2 inhibitors and at 72 hours for those who take COX-1 inhibitor medications.

The platelet-function analyzer (PFA-100 ® ) for evaluating primary hemostasis

The platelet-function analyzer, PFA-100, is a relatively novel method for rapid in vitro global evaluation of primary hemostasis. The aim of this review is to summarize the published studies reporting on the utility of the PFA-100 device as a screening tool for primary hemostasis. Data were identified by searches of the published literature, including PubMed, references from reviews and abstracts from the most important meetings on this topic. The literature data support the use of the PFA-100 as a useful screening tool for the investigation of von Willebrand's disease and other acquired and congenital intrinsic platelet function disorders. Moreover, it is useful for evaluating primary hemostasis before surgical procedures and for monitoring desmopressin therapy in both von Willebrand's disease and platelet function disorders. Given its high sensitivity, speed and simplicity of use, we conclude that the PFA-100 could replace the in vivo bleeding time as a screening test for primary hemostasis in routine clinical practice.

Meloxicam Does Not Affect the Antiplatelet Effect of Aspirin in Healthy Male and Female Volunteers

This study determined if meloxicam, a selective cyclooxygenase (COX)-2 inhibitor, interferes with the antiplatelet effect of aspirin using platelet aggregation and thromboxane (Tx) B(2) endpoints in healthy volunteers. Eight male and 8 female volunteers participated in this open-label, randomized, two-treatment, two-way crossover trial. Treatment 1 was meloxicam (15 mg qd) over 4 days, and then aspirin (100 mg qd) was ingested 2 hours after meloxicam for an additional 7 days. Blood samples were taken 2, 6, and 24 hours after the last dose. Treatment 2 consisted of only aspirin (100 mg) over 2 days. Samples were taken at the same time points. Each subject received both treatments with a 2-week washout between the treatment periods. Treatments were safe and well tolerated. The initial 4-day treatment with meloxicam had no effect on platelet aggregation but reduced serum TxB(2) by 64% +/- 19%. Addition of aspirin (100 mg qd) for 7 days resulted in complete inhibition of aggregation and TxB(2) for 24 hours. Two-day treatment with only 100 mg aspirin also resulted in complete inhibition of platelet aggregation and TxB(2). These results indicate that meloxicam does not affect the ability of aspirin to inhibit COX-1 in platelets, thereby allowing aspirin to effectively prevent platelet aggregation and reduce TxB(2) levels, and that meloxicam is selective for COX-2.

The combination of EPA+DHA and low-dose aspirin ingestion reduces platelet function acutely whereas each alone may not in healthy humans

INTRODUCTION

Aspirin's effectiveness in reducing cardiovascular disease events is inadequate in some individuals, a phenomenon termed aspirin "resistance". The hypothesis that combining low dose aspirin with eicosapentaenoic acid and docosahexaenoic acid (EPA+DHA) reduces platelet function in the acute setting has not been investigated.

PATIENTS AND METHODS

We conducted a clinical trial of EPA+DHA and aspirin ingestion in healthy adults. Fasting blood samples were drawn at baseline and 4 h after supplementation with EPA/DHA (3.4 g/d), aspirin (81 mg), and both. Platelet function was measured using the Platelet Function Analyzer-100 (PFA-100). Plasma lysophosphatidylcholine (LPC), lysophosphatidic acid (LPA), autotaxin, angiogenesis activators, and cytokines were measured.

RESULTS

Platelet function decreased with the combination of aspirin+EPA/DHA (p=0.03) but not with either alone (p>0.05). EPA-LPC increased (p=0.002).

DISCUSSION AND CONCLUSIONS

Our results demonstrate that a potentially beneficial effect on platelet function occurred within 4h after ingestion of low-dose aspirin and EPA+DHA in healthy adults.

Evaluation of the new INNOVANCE® PFA P2Y cartridge in patients with impaired primary haemostasis

Recently, the INNOVANCE® PFA P2Y (P2Y) cartridge of the PFA-100® system (Siemens Healthcare Diagnostics, Marburg, Germany) has been developed for the monitoring of adenosine diphosphate (ADP) P2Y(12) receptor inhibition in patients under dual antiplatelet therapy. The aim of this study was to evaluate the influence of pre-existing defects in primary haemostasis on the P2Y cartridge independent from specific antiplatelet medication. Therefore, the closure time (CT) of the P2Y cartridge was measured in a cohort of 176 patients with assumed bleeding disorders and compared with the results of established methods for the assessment of primary haemostasis. Von Willebrand disease (VWD) was found in 25 patients (14%). The detection rate of the P2Y cartridge regarding VWD was 64% and lower compared to the two conventional cartridges (collagen/epinephrine cartridge, CEPI, 80%; collagen/ADP cartridge, CADP, 76%). In the subgroup of VWD patients with VWF:RCo < 60 IU/dL (n = 22), the correlation analysis and the inter-rater agreement revealed only limited accordance with the two established cartridges. The correlation with the CADP cartridge (C(r) = 0.767, R(2) = 0.461; Kappa = 0.41) was higher than the correlation with the CEPI cartridge. Except for severe forms, platelet function disorders (9 patients, 5%) did not prolong the CT of the P2Y cartridge. Interestingly, the P2Y cartridge was less interference-prone to unspecific medications (23 patients, 13%). As the main conclusion, it must be taken into account that low von Willebrand factor activity can significantly influence the CTs of the P2Y cartridge when using it for the monitoring of antiplatelet therapy.

Voriconazole increases while itraconazole decreases plasma meloxicam concentrations

This study investigated the effect of voriconazole, an inhibitor of cytochrome P450 2C9 (CYP2C9) and CYP3A4, and itraconazole, an inhibitor of CYP3A4, on the pharmacokinetics and pharmacodynamics of meloxicam. Twelve healthy volunteers in a crossover study ingested 15 mg of meloxicam without pretreatment (control), after voriconazole pretreatment, and after itraconazole pretreatment. The plasma concentrations of meloxicam, voriconazole, itraconazole, and thromboxane B(2) (TxB(2)) generation were monitored. Compared to the control phase, voriconazole increased the mean area under the plasma concentration-time curve from 0 to 72 h (AUC(0-72)) of meloxicam by 47% (P < 0.001) and prolonged its mean half-life (t(1/2)) by 51% (P < 0.01), without affecting its mean peak concentration (C(max)). In contrast, itraconazole decreased the mean AUC(0-72) and C(max) of meloxicam by 37% (P < 0.001) and by 64% (P < 0.001), respectively, and prolonged its t(1/2) and time to C(max). The plasma protein unbound fraction of meloxicam was unchanged by voriconazole and itraconazole. Lowered plasma meloxicam concentrations during the itraconazole phase were associated with decreased pharmacodymic effects of meloxicam, as observed by weaker inhibition of TxB(2) synthesis compared to the control and voriconazole phases. Voriconazole increases plasma concentrations of meloxicam, whereas itraconazole, unexpectedly, decreases plasma meloxicam concentrations, possibly by impairing its absorption.

Usefulness of whole blood aggregometry and its comparison with thromboxane generation assay in monitoring acetylsalicylic acid effectiveness--a multiparametric study in rats

BACKGROUND

There is a need for consensus concerning universal methodological criteria for detection of suboptimal response to acetylsalicylic acid (ASA) therapy. Therefore, animal models to test for ASA effectiveness remain of interest. Our objective was to verify the usefulness of multiparametric whole-blood impedance aggregometry and thromboxane A(2) generation, which are the most popular techniques used for monitoring of ASA treatment effectiveness.

METHODS

Using multiparametric analysis of whole-blood impedance aggregometry, we examined which parameters of platelet aggregation or disaggregation allow for the best discrimination between ASA-treated (4 or 40 mg/kg for 60 days) and non-treated male rats. The effectiveness of ASA-mediated inhibition of platelet cyclooxygenase-1 was verified by determination of plasma thromboxane B(2) and urine 11-dehydro-thromboxane B(2), accepted as reference assays for monitoring of ASA-mediated platelet cyclooxygenase-1 inhibition.

RESULTS

Two of the platelet agonists used, collagen (1 mg/L) and arachidonic acid (0.5 mmol/L), allowed discrimination of control and ASA-treated animals, whereas adenosine diphosphate (5 micromol/L) was not effective. It is noteworthy that only ASA-mediated changes in duration of the rising phase for platelet aggregation and the area under the curve for collagen-induced aggregation allowed significant discrimination between low and high ASA dose and remained correlated with the reference parameter, plasma thromboxane B(2).

CONCLUSIONS

Analysis of aggregation curves, routinely based only on the amplitude and rate of platelet aggregation, may not be enough discriminative to distinguish between varying ASA doses and treatment schedules.

Platelet function analyzer (PFA)-100 closure time in the evaluation of platelet disorders and platelet function

BACKGROUND

Closure time (CT), measured by platelet function analyzer (PFA-100) device, is now available to the clinical laboratory as a possible alternative or supplement to the bleeding time test.

AIM

On behalf of the Platelet Physiology Subcommittee of the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis (ISTH-SSC), a working Group was formed to review and make recommendations on the use of the PFA-100 CT in the evaluation of platelet function within the clinical laboratory.

METHODS

The Medline database was searched to review the published information on the PFA-100 CT in the evaluation of platelet disorders and platelet function. This information, and expert opinion, was used to prepare a report and generate consensus recommendations.

RESULTS

Although the PFA-100 CT is abnormal in some forms of platelet disorders, the test does not have sufficient sensitivity or specificity to be used as a screening tool for platelet disorders. A role of the PFA-100 CT in therapeutic monitoring of platelet function remains to be established.

CONCLUSIONS

The PFA-100 closure time should be considered optional in the evaluation of platelet disorders and function, and its use in therapeutic monitoring of platelet function is currently best restricted to research studies and prospective clinical trials.

Cyclooxygenase Isozymes: The Biology of Prostaglandin Synthesis and Inhibition

Nonsteroidal anti-inflammatory drugs (NSAIDs) represent one of the most highly utilized classes of pharmaceutical agents in medicine. All NSAIDs act through inhibiting prostaglandin synthesis, a catalytic activity possessed by two distinct cyclooxygenase (COX) isozymes encoded by separate genes. The discovery of COX-2 launched a new era in NSAID pharmacology, resulting in the synthesis, marketing, and widespread use of COX-2 selective drugs. These pharmaceutical agents have quickly become established as important therapeutic medications with potentially fewer side effects than traditional NSAIDs. Additionally, characterization of the two COX isozymes is allowing the discrimination of the roles each play in physiological processes such as homeostatic maintenance of the gastrointestinal tract, renal function, blood clotting, embryonic implantation, parturition, pain, and fever. Of particular importance has been the investigation of COX-1 and -2 isozymic functions in cancer, dysregulation of inflammation, and Alzheimer's disease. More recently, additional heterogeneity in COX-related proteins has been described, with the finding of variants of COX-1 and COX-2 enzymes. These variants may function in tissue-specific physiological and pathophysiological processes and may represent important new targets for drug therapy.

COX 2 selectivity of non-steroidal anti-inflammatory drugs and perioperative blood loss in hip surgery. A randomized comparison of indomethacin and meloxicam

BACKGROUND

In this prospective randomized study we tested the hypothesis that use of more cyclo-oxygenase 2 (COX 2)-selective non-steroidal anti-inflammatory drugs (NSAIDs) can reduce perioperative blood loss compared with non-selective NSAIDs.

METHODS

Data from 200 patients who underwent total hip replacement were studied. Two NSAIDs were compared: indomethacin 50 mg (n = 82) and meloxicam 15 mg (n = 86). Both NSAIDs were given orally 1 h before surgery.

RESULTS

The two groups were not different with respect to age, gender, ASA class or duration of surgery. When indomethacin was used preoperatively, intraoperative blood loss was 623 +/- 243 mL (mean +/- SD) and postoperative blood loss 410 +/- 340 mL. After meloxicam, these values were 524 +/- 304 mL and 358 +/- 272 mL, respectively. Total perioperative blood loss after meloxicam was 17% (P < 0.05) less than that observed after indomethacin.

CONCLUSION

Perioperative blood loss after meloxicam is less than after indomethacin. These in vivo findings are consistent with in vitro results using selective COX 2 NSAIDs.

[Pharmacology and classification of cyclooxygenase inhibitors]

The discovery of at least two cyclooxygenase (COX) isoenzymes had two major consequences: i) to give a new impetus to the research on lipid metabolism, giving rise to the crystallization of these peculiar membrane enzymes, the characterization of their active sites and their gene regulation, and the identification of new metabolic pathways; ii) the development of new NSAIDs aimed to have an improved safety profile, the coxibs. These drugs are defined by their COX-2 selectivity which is supported by a negligible inhibitory potency on platelet COX-1 in vitro and ex vivo after oral intake of maximal therapeutic doses. However, the coxibs marketed in France (celecoxib, rofecoxib, parecoxib) are not equivalent in terms of selectivity and some drugs developed by pharmaceutical companies (etoricoxib, lumiracoxib) will be even more selective for COX-2. These "new" coxibs are the final step in the theory of COX-2 selectivity and they will probably be helpful to better define the limitations of the therapeutic concept based on a selective inhibition of this iso-enzyme.

Variable inhibition of high-shear-induced platelet plug formation by eptifibatide and tirofiban under conditions of platelet activation and high von Willebrand release: a randomized, placebo-controlled, clinical trial

BACKGROUND

Glycoprotein (GP) IIb/IIIa antagonists have become a mainstay for the treatment of acute coronary syndromes. Yet, they have rarely been evaluated under relevant pathophysiologic conditions, for example, high shear rates in the presence of physiologic calcium concentrations. We compared the efficacy of eptifibatide and tirofiban versus placebo on high shear-induced platelet plug formation in a model in which healthy subjects exhibit von Willebrand factor concentrations and platelet activation comparable to patients with acute coronary syndromes.

METHODS

Thirty male volunteers received 2 ng/kg endotoxin and standard doses of eptifibatide, tirofiban, or placebo over a period of 5 hours in a randomized, double-blinded, placebo-controlled, double-dummy parallel-group trial. Platelet inhibition was measured with the Platelet Function Analyzer-100 (PFA-100) and the Ultegra method.

RESULTS

Although bolus infusion of both GPIIb/IIIa antagonists inhibited high shear-induced platelet plug formation, continuous infusion of eptifibatide prolonged closure times more effectively than did tirofiban (P <.008). Interestingly, tirofiban had only placebo-like effects on platelet plug formation after 2 hours. However, when additional drug was exogenously added, closure time values were maximally prolonged in all cases.

CONCLUSIONS

Standard doses, particularly of tirofiban, have limited impact on high shear-induced platelet plug formation at physiologic Ca(2+) concentrations.

Relationship of arachidonic acid concentration to cyclooxygenase-dependent human platelet aggregation

Inhibition of ex vivo arachidonic acid (AA)-induced aggregation is a biomarker for the isotype selectivity of cyclooxygenase (COX) inhibitors since platelets express COX-1 but not COX-2. At low concentrations, there is broad inter- and intrasubject variability in AA-induced aggregation of platelets ex vivo. This study defined a concentration that reliably induces aggregation without overcoming inhibition by therapeutic aspirin therapy (ASA, 81-mg) treatment. Logistic regression analysis of ex vivo aggregation, induced with increasing concentrations of AA in platelet-rich plasma (PRP), estimated that platelets from > or = 90% of subjects would aggregate at > or = 1.5 mM AA (95% confidence interval [CI], 1.1, 2.1). A concentration of 1.6 mM AA failed to aggregate platelets from 26 healthy volunteers, who had previously aggregated at this concentration, following six daily oral doses of 81 mg of ASA. These data demonstrate that 1.6 mM AA reproducibly induces platelet aggregation in PRP from healthy volunteers without overcoming the antiplatelet effect of daily low-dose aspirin therapy.

Meloxicam and selective COX-2 inhibitors in the management of pain in the palliative care population

This paper discusses the treatment of pain in the palliative care patient, specifically the use of meloxicam and recent advances in agents with cyclooxygenase-2 (COX-2) selectivity. Meloxicam is a nonsteroidal anti-inflammatory drug (NSAID) that preferentially inhibits COX-2 more than cyclooxygenase-1 (COX-1), especially at low doses, thereby offering advantages over traditional nonselective NSAIDs. New COX-2 selective agents are discussed, including valdecoxib, parecoxib, etoricoxib, and COX-189.

The influence of cyclo-oxygenase specificity of non-steroidal anti-inflammatory drugs on bleeding complications in concomitant coumarine users

BACKGROUND

Concomitant use of coumarines and non-steroidal anti-inflammatory drugs (NSAIDs) may induce bleeding complications, due to the inhibition of both coagulant factors and platelet function. Unlike non-selective NSAIDs, cyclo-oxygenase-2 (COX-2)-selective NSAIDs interfere very little with platelet aggregation.

AIM

To determine whether COX-2-selective NSAIDs are associated with less bleeding complications in coumarine users, compared with non-selective NSAIDs.

DESIGN

Prospective, nested case-control study.

METHODS

We studied concomitant coumarine and NSAID users over two years. Patients with bleeding (cases), and frequency-matched patients without bleeding (controls), were sent questionnaires regarding possible risk factors for bleeding. International normalized ratio (INR) values were recorded. Univariate and multivariate analyses were used to detect factors contributing to bleeding.

RESULTS

There were 1491 reported bleeds. NSAIDs were involved in 14.8%; 3.9% involving COX-2-selective NSAIDs. In non-bleeders, 2601 prescriptions with a coumarine/NSAID combination were detected; 9.7% were COX-2-selective. Adjusted ORs (95% CI) for a bleeding complication were 3.07 (1.18-8.03) for non-selective NSAID use, 3.01 (1.42-6.37) for NSAID use > 1 month, and 1.89 (1.03-3.49) for INR > or = 4.0.

DISCUSSION

In coumarine users, COX-2-selective NSAIDs are associated with less bleeding complications than non-selective NSAIDs are. Duration of NSAID use, as well as intensity of coumarine treatment, plays an important additional role. When the coumarine-NSAID combination is inevitable in an individual patient, a COX-2-selective NSAID may be preferred, with careful monitoring of the INR.

Platelet function under aspirin, clopidogrel, and both after ischemic stroke: a case-crossover study

BACKGROUND AND PURPOSE

Combined antiplatelet agents may offer additive protection over single drugs after stroke. We investigated whether platelet activation is reduced under combined aspirin and clopidogrel compared with each drug alone.

METHODS

In a case-crossover study, 31 patients with previous atherothrombotic or lacunar stroke who were treated with aspirin (100 to 300 mg/d) received clopidogrel (75 mg/d) and both aspirin and clopidogrel for 4 weeks. Platelet function in whole blood was studied after each treatment period and in healthy control subjects to assess activation-dependent antigens CD62p and CD63 by flow cytometry and collagen/epinephrine (CEPI-CT) and collagen/ADP (CADP-CT) closure times with the platelet function analyzer PFA-100, which investigates platelet-related function under shear stress.

RESULTS

CD62p expression and CD63 expression were not different under the 3 treatment regimens. CD63 but not CD62p expression was lower in control subjects than in stroke patients regardless of the antiplatelet treatment (P<0.05). CEPI-CT was prolonged under aspirin and aspirin plus clopidogrel compared with clopidogrel monotherapy (P<0.0001). CADP-CT was longer under combination therapy than under aspirin (P=0.0009) or clopidogrel (P=0.0074) or in control subjects (P=0.0010), mainly because of strong prolongation in a patient subgroup (28%).

CONCLUSIONS

CD63 expression reflecting the release of platelet lysosomes is consistently increased after stroke and incompletely suppressed by treatment with aspirin, clopidogrel, or both. The strong prolongation of CADP-CT under combined aspirin and clopidogrel in a patient subgroup may indicate a lower risk of thrombosis but also a higher risk of hemorrhage. The predictive value of platelet activation parameters requires investigation in prospective studies.

Pain intensity after laseruvulopalatoplasty and tonsillectomy

OBJECTIVE

The first objective of this study was to evaluate pain intensity and opioid consumption during the first 24 hours after uvulopalatoplasty and tonsillectomy in the hospital, and the second was to evaluate pain intensity and its progression during the first 2 weeks after surgery at home.

STUDY DESIGN AND SETTINGS

In a prospective parallel group study, 51 patients with uvulopalatoplasty or tonsillectomy were studied. Ketoprofen, a nonsteroidal antiinflammatory drug, and fentanyl citrate, an opioid, were used as analgesics.

RESULTS

Despite ketoprofen infusion and free access to a patient-controlled pump with fentanyl citrate for rescue analgesia, inadequate pain relief was common both after uvulopalatoplasty (35%) and after tonsillectomy (28%) during the first 24 hours after surgery. The consumption of fentanyl citrate was similar after both operations. At home, pain intensity was highest in the mornings during the first 5 days, and 10 patients had some pain still after 2 weeks. Also at home, high pain scores were reported commonly in both groups.

CONCLUSION

Significant pain after uvulopalatoplasty and tonsillectomy lasted for several days. Ketoprofen in the commercial capsule form proved to be too short acting for overnight pain relief.

SIGNIFICANCE

Pain treatment in patients with uvulopalatoplasty and tonsillectomy should be improved to allow patients a peaceful recovery after surgery.

Prescription and Tolerability of Meloxicam in Day-to-Day Practice

The goal of this study was to obtain data for prescription habits, tolerability for patients at high risk, and clinical effectiveness of meloxicam administered at 7.5 mg and 15 mg for various rheumatic diseases under real world prescribing conditions. This was a 3-month large-scale prospective observational cohort study in 4000 medical practices throughout Germany shortly after the introduction of meloxicam. To be eligible, patients had to have a diagnosis of acute or chronic active rheumatic disease for which nonsteroidal antiinflammatory drug (NSAID) therapy was required according to the prescribing information. In this study, 13,307 patients receiving meloxicam prescriptions (7.5 mg in 65% and 15 mg in 33%) were observed. The diagnoses of these patients included osteoarthritis (61%), rheumatoid arthritis (24%), ankylosing spondylitis (1.6%), and other rheumatic conditions (28%). A substantial proportion of high risk patients were enrolled: 12% with a previous history of a perforation, ulceration, and bleeding (PUB), 24% with at least one concomitant cardiovascular disorder, and 26% receiving concomitant antihypertensive medication. Many of the patients (58%) had received NSAIDs before meloxicam, including patients with insufficient prior treatment effectiveness (43%) and those with NSAID-related adverse drug reactions (21%). In 85% and 94% of the patients, respectively, effectiveness and tolerability were rated as good or very good. Quality of life and daily functions improved in 64% to 84% of the patients. Only 0.8% of the patients reported gastrointestinal (GI) adverse drug reactions. Four uncomplicated cases of gastric ulceration, one serious perforated gastric ulcer, and one serious ileus complication were reported after incorrect use or overdosing of meloxicam. Treatment with the selective cyclooxygenase-2 (COX-2) inhibitor meloxicam in doses of 7.5 mg and 15 mg resulted in meaningful treatment responses under real life conditions, despite inclusion of a substantial number of patients with insufficient effectiveness of previous use of non-COX-2 selective NSAIDs. All major GI toxicity (PUB) observed was owing to the fact that prescribing conditions were not respected appropriately. Despite a selection of high risk patients overall, GI, cardiovascular, and renal tolerability was favorable.

Clinical application of the PFA-100

The PFA-100 (platelet function analyzer) is a relatively new tool for the investigation of primary hemostasis. Recent studies have shown its utility as a screening tool for investigating possible von Willebrand disorder (VWD) and various platelet disorders. More recently, the PFA-100 has been shown to be valuable in monitoring desmopressin acetate (DDAVP) therapy in both VWD and platelet disorders. The PFA-100 has also been evaluated in many other studies for its utility in assessing drug effects, for potential monitoring of antiplatelet medication (including aspirin), or for evaluation of overall primary hemostasis in various clinical disorders or during surgical procedures. This article reviews current findings and highlights the benefits and limitations of the clinical utility of the PFA-100. Ultimately, the greatest strengths of the PFA-100 are its simplicity of use and excellent sensitivity to particular hemostatic disturbances such as VWD, platelet disorders, and platelet-affecting medication. However, because it is thus a global test system, this also creates a significant limitation because the PFA-100 is not specific for, nor predictive of, any particular disorder. However, used appropriately, the PFA-100 can be considered a worthwhile addition to any hemostasis laboratory involved in the diagnosis or therapeutic monitoring of bleeding disorders and potentially of antiplatelet medication. This review should be valuable to both hemostasis scientists and clinical specialists.

Effects of meloxicam on platelet function in healthy adults: a randomized, double-blind, placebo-controlled trial

Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit cyclooxygenase-1 (COX-1), thereby inhibiting platelet function via blockade of thromboxane A2 (TxA2) formation, and COX-2, the enzyme that mediates inflammatory responses. Meloxicam is a relatively COX-2-selective anti-arthritis drug that shows significant TxA2 inhibition, albeit less than traditional NSAIDs. A randomized, double-blind, placebo-controlled trial was conducted in 79 healthy adults to compare the effects of once-daily therapeutic (7.5 mg, 15 mg) and supratherapeutic (30 mg) doses of meloxicam with extended-release indomethacin (Indo-ER 75 mg once daily) on bleeding time, TxA2 formation, and platelet aggregation. The authors measured platelet aggregation to COX-1-dependent (ADP arachidonate) and COX-1-independent (high-dose collagen) agonists, bleeding time, serum TxB2, and clotting times (aPTT and PT) after 8 days' administration and at 3 and 6 hours after steady-state dosing. Meloxicam significantly decreased TxB2 production compared with placebo in a dose-dependent fashion, reaching a peak of 77% inhibition 6 hours after 30 mg meloxicam; Indo-ER blocked TxB2 formation by 96% at the same time point. However, neither acute nor 8 days' administration of meloxicam at any dose caused a significant increase in bleeding time or inhibition of platelet aggregation to any agonist when compared with placebo. By contrast, Indo-ER significantly increased the bleeding time and inhibited platelet aggregation to COX-1-dependent agonists 6 hours after dosing. Clotting times were unaffected by any drug. It was concluded that unlike nonselective NSAIDs, meloxicam's blockade of TxA2 formation (even at supratherapeutic doses) does not reach levels that result in decreased in vivo platelet function, as measured by bleeding time and aggregometry. In this study of healthy subjects, meloxicam did not interfere with platelet-mediated hemostasis.

A comparison of the effects of nabumetone vs meloxicam on serum thromboxane B2 and platelet function in healthy volunteers

AIMS

To compare the effects of nabumetone and meloxicam, two cyclo-oxygenase-2 (COX-2) preferential nonsteroidal anti-inflammatory drugs (NSAIDs), on platelet COX-1 activity and platelet function.

METHODS

Twelve healthy volunteers (3 male, 9 female, median age 22 years) participated in an open, randomized, cross-over trial of nabumetone 1000 mg twice daily vs meloxicam 7.5 mg twice daily during 1 week with 2 weeks wash-out. After a second 2 week wash-out period, one dose of indomethacin 50 mg was given as a positive control to check for NSAID induced inhibition of platelet function. COX-1 inhibition was measured as percentage inhibition of serum TXB2 generation in clotting whole blood, and as closure time with use of the platelet function analyser PFA-100. Data are reported as median with range. Paired variables were analysed using Wilcoxons signed rank test.

RESULTS

TXB2 levels decreased significantly after all three medications, but percentage inhibition after nabumetone and indomethacin (88% and 97%, respectively) was significantly higher than after meloxicam (63%) (P<0.05). Closure times increased significantly after administration of all three medications (P<0.05). Increases in closure time after administration did not differ between nabumetone and meloxicam (24% and 14%, respectively), but were significantly larger after indomethacin administration (63%) (P<0.01).

CONCLUSIONS

In the maximum registered dosage, nabumetone inhibits thromboxane production much more than meloxicam, signifying less COX-2 selectivity of the former. However, both nabumetone and meloxicam cause only minor impairment in platelet function in comparison with indomethacin and the difference between them is not significant.

Cyclooxygenase selectivity of non-steroid anti-inflammatory drugs in humans: ex vivo evaluation

We have recently described a novel assay to assess ex vivo the activity and selectivity on cyclooxygenase-1 and -2 (EC 1.14.99.1) of non-steroid anti-inflammatory drugs (NSAID) administered to rats [Br. J. Pharmacol. 126 (1999) 1824.]. Here, we have extended these studies to humans. Healthy male volunteers were given orally one of the following drugs (mg) for 5 days: etodolac (200 or 400 b.i.d.), meloxicam (7.5 or 15 q.d.), nimesulide (100 or 200 b.i.d.), nabumetone (500 or 1000 b.i.d.) or naproxen (500 b.i.d.). Blood samples were withdrawn from the volunteers before and up to 24 h after the last dose. Plasma obtained from the blood was tested for its ability to inhibit prostanoid formation in interleukin-1beta-treated A549 cells (cyclooxygenase-2 system) and human washed platelets (cyclooxygenase-1 system). Plasma from etodolac-treated subjects demonstrated a slight selectivity towards the inhibition of cyclooxygenase-2. This effect was more prominent in plasma from subjects receiving meloxicam or nimesulide. Plasma from nabumetone-treated subjects showed no or little selectivity towards cyclooxygenase-1 depending on the dose of drug administered, while plasma taken from subjects receiving naproxen was more active at inhibiting cyclooxygenase-1 than cyclooxygenase-2. In conclusion, we have demonstrated that this assay can be used to assess ex vivo the relative activity against cyclooxygenase-1 and cyclooxygenase-2 of NSAIDs consumed by human volunteers. It is to be hoped that data from such systems will aid in our understanding of the relationships between the differential inhibition of cyclooxygenase-1 and cyclooxygenase-2 by NSAIDs and their reported efficacies and (gastrointestinal) toxicities.

Utility of the PFA-100 for assessing bleeding disorders and monitoring therapy: a review of analytical variables, benefits and limitations

The PFA-100 (platelet function analyser) is a relatively new tool for the investigation of primary haemostasis. Recent studies have shown its utility in monitoring antiplatelet therapy (including aspirin) and as a screening tool for investigating possible von Willebrand disease (vWD) and various platelet disorders. More recently, the PFA-100 has been shown to be of value in monitoring DDAVP therapy in both vWD and platelet disorders. This paper reviews current findings, details the utility of the PFA-100 for some of these purposes, as well as reviewing analytical variables that may complicate the interpretation of results. The author highlights the benefits, as well as noting the limitations, of its use. Ultimately, the greatest strengths of the PFA-100 are its simplicity in use and excellent sensitivity to particular haemostatic disturbances such as vWD, platelet disorders and platelet-affecting medication. However, because it is thus a 'global' test system, this also creates a significant limitation, as the PFA-100 is not specific for, nor predictive of, any particular disorder. However, utilized appropriately, the PFA-100 can be considered a worthwhile addition to any haemostasis laboratory involved in the diagnosis or therapeutic-monitoring of bleeding disorders including vWD and platelet-dysfunctions. This review should be of value to both haemostasis scientists and clinical specialists.

Meloxicam

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Are the biologic and clinical effects of the COX-2-specific inhibitors an advance compared with the effects of traditional NSAIDs?

This has been an unusual year for the accumulation of evidence regarding the clinical effects of inhibition of cyclooxygenase (COX)-1 and COX-2. This article reviews the available data regarding the clinical effects of the new COX-2-specific inhibitors, and speculates about the importance of the data as they relate to the treatment of patients with chronic pain and/or inflammation.

Efficacy and tolerability of meloxicam in an observational, controlled cohort study in patients with rheumatic disease

BACKGROUND

Meloxicam is a nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase-2 without affecting platelet aggregation.

OBJECTIVE

The goal of this study was to assess the efficacy and tolerability of meloxicam under natural prescribing conditions for up to 6 months.

METHODS

This was a multicenter, prospective, observational cohort study. Participating centers were randomized to 1 of 2 groups: the meloxicam-only group, and the group who received comparator NSAIDs (ie, diclofenac, ibuprofen, piroxicam, or indomethacin).

RESULTS

A total of 4526 patients received either meloxicam (n = 2530) or a comparator NSAID (n = 1996). Treatment groups were comparable in terms of observed efficacy measures. Meloxicam patients had significantly lower rates of reported gastrointestinal (GI) adverse drug reactions (1.80% vs 3.20%; P = 0.003), including dyspepsia (0.08% vs 0.35%; P = 0.049), abdominal pain (0.91% vs 1.90%; P = 0.006), gastritis (0.08% vs 0.60%; P = 0.002), and GI bleeding (0.08% vs 0.50%; P = 0.007), compared with those receiving comparator NSAIDs.

CONCLUSION

There was evidence that meloxicam was prescribed preferentially to patients who had not responded to NSAIDs previously, who had previously experienced NSAID-induced side effects (and so were at high risk for developing NSAID-induced GI toxicity), or who were more seriously impaired. The nonrandomized and unblinded nature of this study limits the conclusions that can be drawn concerning efficacy or tolerability. Nevertheless, the study results are consistent with the favorable GI tolerability seen with meloxicam in double-blind comparative trials.