Pharmacokinetics, COX-2 specificity, and tolerability of supratherapeutic doses of rofecoxib in humans

Evaluation of surface acetylated and internally quaternized poly(propylene imine) dendrimer as a biocompatible drug carrier for piroxicam as a model drug

Two types of new surface acetylated and internally quaternized poly(propylene imine) dendrimers QPPI-NHAc (G2)/(G3) were prepared, characterized and then demonstrated as potential and biocompatible drug carriers using piroxicam as a model drug.

Are there any differences among non-steroidal anti-inflammatory drugs? Focus on nimesulide

Although the efficacy of non-steroidal anti-inflammatory drugs (NSAIDs) as anti-inflammatory, analgesic and antipyretic agents is well established, there is still an open question as to whether their different pharmacokinetic and pharmacodynamic characteristics do have a different clinical impact in treating rheumatology patients. The mechanism related to the anti-inflammatory activity of these drugs is mainly related to the inhibition of the cyclo-oxygenase (COX)-2 isoform, whereas inhibition of COX-1 is associated with the side effects of these drugs. However, some NSAIDs exert their anti-inflammatory and analgesic action by additional mechanisms. The NSAID nimesulide, along with its preferential activity on COX-2 and a short half-life that correlates with a rapid onset of analgesic action, acts also through a variety of COX-independent pathways that contributes to its potent antiinflammatory and analgesic activity. The pathways affected by nimesulide include inhibition of tumour necrosis factor alpha (TNF-α) release, histamine release, reactive oxygen species production and chondrocyte death. Furthermore, the use of nimesulide has been associated with reduced levels of matrix metalloproteases and other biomarkers of joint destruction, suggesting it may have a protective effect against disease progression. Due to its multifactorial mechanism as well as to rapid onset of the analgesic action, nimesulide represents an appealing therapeutic choice for the treatment of rheumatology patients.

Effects of non-steroidal anti-inflammatory drugs on proliferation, differentiation and migration in equine mesenchymal stem cells

In equine medicine, stem cell therapies for orthopaedic diseases are routinely accompanied by application of NSAIDs (non-steroidal anti-inflammatory drugs). Thus, it has to be analysed how NSAIDs actually affect the growth and differentiation potential of MSCs (mesenchymal stem cells) in vitro in order to predict the influence of NSAIDs such as phenylbutazone, meloxicam, celecoxib and flunixin on MSCs after grafting in vivo. The effects of NSAIDs were evaluated regarding cell viability and proliferation. Additionally, the multilineage differentiation capacity and cell migration was analysed. NSAIDs at lower concentrations (0.1-1 μM for celecoxib and meloxicam and 10-50 μM for flunixin) exert a positive effect on cell proliferation and migration, while at higher concentrations (10-200 μM for celecoxib and meloxicam and 100-1000 μM for flunixin and phenylbutazone), there is rather a negative influence. While there is hardly any influence on the adipogenic as well as on the chondrogenic MSC differentiation, the osteogenic differentiation potential, as demonstrated with the von Kossa staining, is significantly disturbed. Thus, it can be concluded that the effects of NSAIDs on MSCs are largely dependent on the concentrations used. Additionally, for some differentiation lineages, also the choice of NSAID is critical.

Prophylactic, prandial rofecoxib treatment lacks efficacy against acute PTZ-induced seizure generation and kindling acquisition

PURPOSE

The goal of this study was to determine whether prophylactic prandial administration of rofecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, could alter seizure generation, kindling acquisition, and/or kindling maintenance in the mouse pentylenetetrazole (PTZ) epilepsy model.

METHODS

Male CD-1 mice were fed ad libitum with control chow or chow formulated to deliver 30 mg/kg/day rofecoxib. After 5 days, mice were treated with a single dose of 40 or 55 mg/kg PTZ (acute paradigm) or 40 mg/kg PTZ delivered daily (kindling paradigm). Seizure severity was scored on a four-point behavioral scale and COX-2 expression was assessed in brain slices from a subset of mice 3 h or 72 h after acute PTZ or following establishment of kindling.

KEY FINDINGS

Hippocampal COX-2 expression was transiently upregulated 3 h after an acute PTZ-induced convulsion and returned to baseline levels within 72 h, whereas it remained elevated for at least 72 h after the final seizure in the kindling paradigm. Despite this increase, chronic rofecoxib treatment did not attenuate the severity of acute PTZ-induced seizures and failed to alter kindling development or maintenance.

SIGNIFICANCE

The present study demonstrates that prophylactic, prandial rofecoxib treatment lacks efficacy against acute PTZ-induced seizure generation and kindling acquisition, and does not reverse the kindled state once established.

COX-2 Inhibition by Use of Rofecoxib or High Dose Aspirin Enhances ADP-Induced Platelet Aggregation in Fresh Blood

Aim:

Increased cardiovascular risk after use of selective or nonselective cyclooxygenase-2 (COX-2)-inhibitors might partly be caused by enhanced platelet aggregability. However, an effect of COX-2 inhibition on platelets has so far not been observed in humans.

Methods:

We tested in healthy volunteers the effect of COX-2-inhibition nearly in-vivo, i.e. immediately after and even during blood sampling.

Results:

Measurement within 2 minutes after venipuncture, but not 60 minutes later, showed that 50 mg of rofecoxib (n=12) or 500 (n=8) or 1000 (n=8) mg of aspirin increased ADP-induced platelet aggregation in a whole-blood aggregometer to, respectively, 152, 176 and 204 % of basal level (p<0.01). No significant differences in aggregability were observed after ingestion of 80 mg of aspirin (n=16), or placebo (n=8). Plasma 6-keto-PGF1α was decreased to 74 % after rofecoxib and to 76 and 70 % after 500 and 1000 mg of aspirin but did not change after low dose aspirin. Continuous photometrical measurement of aggregation in blood flowing from a cannulated vein revealed that high dose aspirin did not elicit aggregation by itself, but increased ADP-induced aggregation in proportion to the decrease in prostacyclin formation (r=0.68, p = 0.004). Since in these experiments thromboxane production was virtually absent, the enhanced aggregation after partial COX-2 inhibition was not caused by unopposed thromboxane formation.

Conclusions:

We conclude that both selective and nonselective COX-2 inhibition enhances ADP-induced platelet aggregation in humans. This effect can only be detected during or immediately after venipuncture, possibly because of the short half-life of prostacyclin.

Experimental Study of COX-2 Selective and Traditional Non-steroidal Anti-inflammatory Drugs in Total Hip Replacement

This study investigated the effects of non-steroidal anti-inflammatory drugs (NSAIDs) on peri-operative blood loss during elective total hip replacement. Patients were randomized to receive enteric-coated diclofenac 50 mg ( n = 18), rofecoxib 12.5 mg ( n = 17) or placebo ( n = 16) administered orally three times daily for 2 weeks prior to surgery. Severe adverse effects resulting in discontinuation of trial participation occurred in six patients in the diclofenac group, five patients in the rofecoxib group and two patients in the placebo group; all drop-outs occurred at various times after surgery. Compared with placebo, peri-operative blood loss increased by 32% in the diclofenac group and by 7% in the rofecoxib group. Total mean ± SD blood loss was 1040 ± 136 ml in the diclofenac group, 844 ± 83 ml in the rofecoxib group and 789 ± 82 ml in the placebo group. Thus, administering a non-selective NSAID 2 weeks prior to elective total hip replacement significantly increases peri-operative blood loss.

Celecoxib and ankylosing spondylitis

It is now over 100 years since the arrival of aspirin and, from the mid-20th Century onwards, we have seen numerous attempts at providing society with safer and more efficacious nonsteroidal drugs. Ironically, while aspirin went from strength to strength with an ever-increasing pharmaceutical profile, new nonsteroidal anti-inflammatory drugs arrived and disappeared with rapid succession. Finally, there appears to have been a breakthrough with the development of the coxibs but concern has recently developed because of potential toxic cardiovascular reactions. Although originally studied in rheumatoid arthritis and degenerative arthropathy, the coxibs have now been investigated in ankylosing spondylitis and efficacy appears to be favorable and, to date, there is little evidence of toxicity, although problems in the nonspondylarthropathic arena may spill over into the seronegative spondylarthritides.

Effects of anti-inflammatory drugs on proliferation, cytotoxicity and osteogenesis in bone marrow mesenchymal stem cells

Nonsteroidal anti-inflammatory drugs (NSAIDs) were found to suppress proliferation and induce cell death in cultured osteoblasts, and steroids were found to decrease the osteogenesis potential of mesenchymal stem cells. In this study, we further tested the effects of anti-inflammatory drugs (AIDs) on the functions of bone marrow mesenchymal stem cells (BMSCs). The BMSCs from mice (D1-cells) and humans (hBMSCs) were treated with dexamethasone (10(-7) to 10(-6) M), cyclooxygenase-2 (COX-2) selective NSAIDs (10(-6) to 10(-5) M) and non-selective NSAIDs (10(-5) to 10(-4) M). Drug effects on proliferation, cell cycle kinetics, cytotoxicity and mRNA and protein expressions of cell cycle regulators were tested. The osteogenesis potential of D1-cells were evaluated by testing mRNA expressions of type Ialpha collagen and osteocalcin 2-8 days after treatments, and testing mineralization 1-3 weeks after treatments. The results showed that all the tested drugs suppressed proliferation and arrested cell cycle of D1-cells, but no significant cytotoxic effects was found. Prostaglandin E1, E2 and F2alpha couldn't rescue the effects of AIDs on proliferation. The p27kip1 expression was up-regulated by indomethacin, celecoxib and dexamethasone in both D1-cells and hBMSCs. Higher concentrations of indomethacin and dexamethasone also up-regulated p21Cip1/Waf1 expression in hBMSCs, and so did celecoxib on D1-cells. Expressions of cyclin E1 and E2 were down-regulated by these AIDs in D-cells, while only cyclin E2 was down-regulated by dexamethasone in hBMSCs. All the tested NSAIDs revealed no obvious detrimental effects on osteogenic differentiation of D1-cells. These results suggest that the proliferation suppression of AIDs on BMSCs may act via affecting expressions of cell cycle regulators, but not prostaglandin-related mechanisms.

The effects of the short-term administration of low therapeutic doses of anti-COX-2 agents on the healing of fractures

We have evaluated the effect of the short-term administration of low therapeutic doses of modern COX-2 inhibitors on the healing of fractures.

A total of 40 adult male New Zealand rabbits were divided into five groups. A mid-diaphyseal osteotomy of the right ulna was performed and either normal saline, prednisolone, indometacin, meloxicam or rofecoxib was administered for five days. Radiological, biomechanical and histomorphometric evaluation was performed at six weeks.

In the group in which the highly selective anti-COX-2 agent, rofecoxib, was used the incidence of radiologically-incomplete union was similar to that in the control group. All the biomechanical parameters were statistically significantly lower in both the prednisolone and indometacin (p = 0.01) and in the meloxicam (p = 0.04) groups compared with the control group. Only the fracture load values were found to be statistically significantly lower (p = 0.05) in the rofecoxib group. Histomorphometric parameters were adversely affected in all groups with the specimens of the rofecoxib group showing the least negative effect.

Our findings indicated that the short-term administration of low therapeutic doses of a highly selective COX-2 inhibitor had a minor negative effect on bone healing.

Rofecoxib is a potent inhibitor of cytochrome P450 1A2: studies with tizanidine and caffeine in healthy subjects

AIMS

Case reports suggest an interaction between rofecoxib and the CYP1A2 substrate tizanidine. Our objectives were to explore the extent and mechanism of this possible interaction and to determine the CYP1A2 inhibitory potency of rofecoxib.

METHODS

In a randomized, double-blind, two-phase cross-over study, nine healthy subjects took 25 mg rofecoxib or placebo daily for 4 days and, on day 4, each ingested 4 mg tizanidine. Plasma concentrations and the urinary excretion of tizanidine, its metabolites (M) and rofecoxib, and pharmacodynamic variables were measured up to 24 h. On day 3, a caffeine test was performed to estimate CYP1A2 activity.

RESULTS

Rofecoxib increased the area under the plasma concentration-time curve (AUC(0-infinity)) of tizanidine by 13.6-fold [95% confidence interval (CI) 8.0, 15.6; P < 0.001), peak plasma concentration (C(max)) by 6.1-fold (4.8, 7.3; P < 0.001) and elimination half-life (t(1/2)) from 1.6 to 3.0 h (P < 0.001). Consequently, rofecoxib markedly increased the blood pressure-lowering and sedative effects of tizanidine (P < 0.05). Rofecoxib increased several fold the tizanidine/M-3 and tizanidine/M-4 ratios in plasma and urine and the tizanidine/M-5, tizanidine/M-9 and tizanidine/M-10 ratios in urine (P < 0.05). In addition, it increased the plasma caffeine/paraxanthine ratio by 2.4-fold (95% CI 1.4, 3.4; P = 0.008) and this ratio correlated with the tizanidine/metabolite ratios. Finally, the AUC(0-25) of rofecoxib correlated with the placebo phase caffeine/paraxanthine ratio (r = 0.80, P = 0.01).

CONCLUSIONS

Rofecoxib is a potent inhibitor of CYP1A2 and it greatly increases the plasma concentrations and adverse effects of tizanidine. The findings suggest that rofecoxib itself is also metabolized by CYP1A2, raising concerns about interactions between rofecoxib and other CYP1A2 substrate and inhibitor drugs.

Oral treatment with rofecoxib reduces hippocampal excitotoxic neurodegeneration

The purpose of this study was to determine whether the selective cyclooxygenase-2 (COX-2) inhibitor rofecoxib [4-[4-(methylsulfonyl)phenyl]-3-phenyl-2(5H)-furanone] could effectively prevent hippocampal neuronal injury in an animal model of excitotoxic neurodegeneration. COX-2 protein levels increased between 3 and 6 h, peaked at 12 h, and declined to near baseline levels 24 h after injection of N-methyl-d-aspartate (NMDA; 18 nmol) into the CA1 region of the left hippocampus. Mice that were fed ad libitum a control rodent diet for 4 days before and 3 days after injection of NMDA demonstrated marked neuronal loss in the primary cell layers of the ipsilateral CA1, CA3, and dentate gyrus (50, 30, and 20% cell loss, respectively). This injury was potently and dose-dependently reduced by feeding animals a diet standardized to deliver 15 or 30 mg/kg rofecoxib per day. Neurodegeneration in the CA1 region was reduced by 30.1 +/- 5.6 and 51.5 +/- 9.0%, respectively; in the CA3 by 64.6 +/- 12.4 and 69.0 +/- 14.1%, respectively; and in the dentate gyrus by 47.8 +/- 15.2 and 58.0 +/- 18.2%, respectively. Moreover, rofecoxib chow slightly but significantly reduced injury-induced brain edema. These findings demonstrate that rofecoxib can ameliorate excitotoxic neuronal injury in vivo and, as such, may be a particularly promising pharmaceutical for the treatment of neurological diseases associated with overactivation of NMDA receptors.

Effects of non-steroidal anti-inflammatory drugs on cell proliferation and death in cultured epiphyseal-articular chondrocytes of fetal rats

Previous reports indicated that non-steroidal anti-inflammatory drugs (NSAIDs) suppress bone repair. Our previous study further found that ketorolac delayed the endochondral bone formation, and the critical effective timing was at the early stage of repair. Furthermore, we found that NSAIDs suppressed proliferation and induced cell death of cultured osteoblasts. In this study, we hypothesized that chondrocytic proliferation and death, which plays an important role at the early stage of endochondral bone formation, might be affected by NSAIDs. Non-selective NSAIDs, indomethacin, ketorolac, diclofenac and piroxicam; cyclooxygenase-2 (COX-2) selective NSAIDs, celecoxib and DFU (an analog of rofecoxib); prostaglandins (PGs), PGE1, PGE2 and PGF2alpha; and each NSAID plus each PG were tested. The effects of NSAIDs on proliferation, cell cycle kinetics, cytotoxicity and cell death of epiphyseal-articular chondrocytes of fetal rats were examined. The results showed that all the tested NSAIDs, except DFU, inhibited thymidine incorporation of chondrocytes at a concentration range (10(-8) to 10(-4)M) covering the theoretic therapeutic concentrations. Cell cycle was arrested by NSAIDs at the G(0)/G(1) phase. Upon a 24h treatment, LDH leakage and cell death (both apoptosis and necrosis) were significantly induced by the four non-selective NSAIDs in chondrocyte cultures. However, COX-2 inhibitors revealed non-significant effects on cytotoxicity of chondrocytes except higher concentration of celecoxib (10(-4)M). Replenishments of PGE1, PGE2 or PGF2alpha could not reverse the effects of NSAIDs on chondrocytic proliferation and cytotoxicity. In this study, we found that therapeutic concentrations of non-selective NSAIDs caused proliferation suppression and cell death of chondrocytes, suggesting these adverse effects may be one of the reasons that NSAIDs delay the endochondral ossification during bone repair found in previous studies. Furthermore, these effects of NSAIDs may act via PG-independent mechanisms. COX-2 selective NSAIDs showed less deleterious effects on chondrocytic proliferation and death.

Studies on dissolution enhancement and mathematical modeling of drug release of a poorly water-soluble drug using water-soluble carriers

Role of various water-soluble carriers was studied for dissolution enhancement of a poorly soluble model drug, rofecoxib, using solid dispersion approach. Diverse carriers viz. polyethylene glycols (PEG 4000 and 6000), polyglycolized fatty acid ester (Gelucire 44/14), polyvinylpyrollidone K25 (PVP), poloxamers (Lutrol F127 and F68), polyols (mannitol, sorbitol), organic acid (citric acid) and hydrotropes (urea, nicotinamide) were investigated for the purpose. Phase-solubility studies revealed AL type of curves for each carrier, indicating linear increase in drug solubility with carrier concentration. The sign and magnitude of the thermodynamic parameter, Gibbs free energy of transfer, indicated spontaneity of solubilization process. All the solid dispersions showed dissolution improvement vis-à-vis pure drug to varying degrees, with citric acid, PVP and poloxamers as the most promising carriers. Mathematical modeling of in vitro dissolution data indicated the best fitting with Korsemeyer-Peppas model and the drug release kinetics primarily as Fickian diffusion. Solid state characterization of the drug-poloxamer binary system using XRD, FTIR, DSC and SEM techniques revealed distinct loss of drug crystallinity in the formulation, ostensibly accounting for enhancement in dissolution rate.

Increased systolic blood pressure with rofecoxib in congenital furosemide-like salt loss

BACKGROUND

To analyse whether congenital furosemide- or thiazide-like renal salt loss protects against the potential prohypertensive effects of two cyclooxygenase (COX) inhibitors: rofecoxib, a COX-2 selective inhibitor, and indomethacin, an unselective COX-inhibitor.

METHODS

In a retrospective analysis, the effects of rofecoxib and indomethacin on blood pressure (bp: transformed into age-independent standard deviation scores (SDS) values), creatinine clearance (CRC), fractional excretion of sodium (FeNa), and renal excretion of systemic prostaglandins were studied in 28 patients with a genetically proven congenital hypokalaemic salt-losing tubulopathy (SLT) (11 female and 17 male, age: 2-25 years), 19 with a furosemide-like SLT, and nine with a thiazide-like SLT.

RESULTS

In furosemide-like SLT patients, systolic SDS bp values were significantly higher with rofecoxib (1.03 +/- 0.16 SDS, n = 107) compared with indomethacin (0.56 +/- 0.09 SDS, n = 282; P = 0.007, 95% CI: 0.12-0.8). Without the drugs, systolic SDS bp values were elevated by 0.63 +/- 0.11 SDS, n = 164. Both drugs reduced renin and aldosterone-plasma levels to a similar extent. SDS values were significantly correlated with the excretion of the vasoconstrictor thromboxane (T x B2) (R2: 0.038, P = 0.021, n: 159), but not with CRC or FeNa. Blood pressure was not increased in thiazide-like SLT patients treated with rofecoxib.

CONCLUSION

Congenital furosemide-like renal salt loss does not protect against the prohypertensive effects of rofecoxib. The positive correlation between bp SDS values with T x B2 but not with FeNa or CRC point towards an altered vascular homeostasis as one mechanism increasing blood pressure.

Effect of nonsteroidal anti-inflammatory drugs with varying extent of COX-2-COX-1 selectivity on urinary sodium and potassium excretion in the rat

Nonsteroidal anti-inflammatory drugs (NSAIDs) have different selectivity to inhibit cyclooxygenase-1 (COX-1) and COX-2. Treatment with NSAIDs has been associated with kidney side effects. We compared the effect of a selected group of NSAIDs with different COX-2--COX-1 selectivities on urinary sodium and potassium excretion in rats. Each treatment with rofecoxib, celecoxib, meloxicam, diclofenac, and flurbiprofen (30, 120, 9, 30, and 125 mg/kg, respectively) and placebo was administered orally once daily for 4 days. Urine was collected 0-8 h after each dose. Urinary sodium and potassium excretion and urine flow rate were compared with placebo. As compared with placebo, rofecoxib, celecoxib, diclofenac, and flurbiprofen significantly reduced excretion rate of sodium (rofecoxib, 0.28 +/- 0.02 vs. 0.41 +/- 0.03; celecoxib, 0.23 +/- 0.03 vs. 0.48 +/- 0.04; diclofenac, 0.09 +/- 0.02 vs. 0.46 +/- 0.03; and flurbiprofen, 0.11 +/- 0.02 vs. 0.47 +/- 0.02 micromol/(min x 100 g)) and potassium (rofecoxib, 0.55 +/- 0.04 vs. 0.68 +/- 0.04; celecoxib, 0.50 +/- 0.06 vs. 0.72 +/- 0.06; diclofenac, 0.26 +/- 0.05 vs. 0.67 +/- 0.04; and flurbiprofen, 0.35 +/- 0.05 vs. 0.62 +/- 0.03 micromol/ (min x 100 g)). Rofecoxib and flurbiprofen significantly reduced urine flow rate. Meloxicam had no significant effect on either sodium and potassium excretion or on the urine flow rate. At the examined dosage level, no relationship was found between reported COX-2--COX-1 selectivity and urinary electrolytes excretion.

The time to onset and overall analgesic efficacy of rofecoxib 50 mg: a meta-analysis of 13 randomized clinical trials

OBJECTIVE

To determine the time to onset of analgesia of rofecoxib based on a patient-level meta-analysis of randomized, placebo-controlled, postoperative oral surgery pain studies.

METHODS

A search on MEDLINE and of Merck data on file was conducted to identify studies that met the inclusion criteria. Meta-analysis inclusion criteria required that patients were treated with a single oral dose of rofecoxib 50 mg when they experienced moderate or severe pain after surgical extraction of > or = 2 third molars; study design involved patient randomization, double-blinding, and matching placebo, and onset data from individual patients were available. The meta-analysis of time to onset also required that studies used the two-stopwatch method. Eleven studies fulfilled the onset criteria and included patients who received a single dose of rofecoxib 50 mg (N = 1220) or placebo (N = 483). These studies were analyzed to determine time to onset of analgesia, time to perceptible pain relief, percentage of patients achieving onset of analgesia, and duration of analgesia. Six of the 11 studies included a nonselective nonsteroidal anti-inflammatory drug (N = 303) and were included in the onset meta-analysis for comparison. The meta-analysis of overall efficacy also required that data on total pain relief scores over 8 hours were available. Over-all effectiveness of analgesia was based on analysis of 13 studies involving 1330 rofecoxib patients and 570 placebo patients on the endpoints of total pain relief scores over 8 hours and patient global assessment of response to therapy at 24 hours. Eight of the 13 studies with a nonselective nonsteroidal anti-inflammatory drug comparator (N = 391) were included for the efficacy meta-analysis.

RESULTS

Patient demographics and baseline characteristics were similar across treatment groups in each study. Median time to onset of analgesia for rofecoxib was 34 minutes (95% CI, 31-38 minutes), significantly faster than placebo, which did not achieve onset within the 4 hours the assessment was conducted (P < 0.001). Duration of analgesia for rofecoxib 50 mg was > 24 hours. Rofecoxib achieved a greater mean total pain relief score over 8 hours than placebo (17.4 versus 4.4; P < 0.001) and a greater patient response rate on patient global assessment of response to therapy at 24 hours than placebo (73% versus 16%; P < 0.001). Outcomes were similar between the rofecoxib group and the nonselective nonsteroidal anti-inflammatory drug group.

CONCLUSION

In this meta-analysis of over 1200 rofecoxib-treated patients, a single dose of rofecoxib 50 mg demonstrated a rapid onset of analgesia in approximately half an hour combined with sustained effectiveness, supporting its use as a treatment of acute pain.

Superiority of the gastroduodenal safety profile of licofelone over rofecoxib, a COX-2 selective inhibitor, in dogs

This study assessed the gastroduodenal safety profile of licofelone, a new nonsteroidal anti-inflammatory drug with dual inhibitory activity against 5-lipoxygenase and cyclo-oxygenase (COX), by using endoscopic evaluations and by comparing licofelone to rofecoxib, a selective COX-2 inhibitor. Twenty-one dogs underwent blinded gastroduodenoscopies, during which the mucosa of the gastroduodenal tract was assessed and scored. Blood analyses were monitored on days 0 (baseline), 14, 28, 42, and 56. Examinations to detect fecal occult blood were performed daily. Dogs were randomly assigned to three groups that received either a placebo, licofelone at a dose of 2.5 mg/kg twice daily, or rofecoxib at a dose of 0.5 mg/kg daily, respectively. Significant differences between the groups in gastric (P = 0.003), duodenal (P = 0.009), and gastroduodenal (P = 0.002) endoscopic lesion scores were observed at day 56. Rofecoxib-treated dogs had more lesions in all areas when compared with placebo-treated dogs, more duodenal lesions when compared with licofelone-treated dogs and more lesions than they had at baseline. In contrast to licofelone, rofecoxib was found to induce significant gastric and gastroduodenal lesions in dogs that lacked pre-existing lesions at baseline. Blood analyses and fecal examinations did not reveal abnormalities in any of the experimental groups. Treatment with licofelone was well tolerated and was shown to be safer than rofecoxib in terms of upper gastrointestinal damage. In this way, this study demonstrates the gastroduodenal safety profile of licofelone for chronic treatment.

Cerebrospinal Fluid and Plasma Pharmacokinetics of the Cyclooxygenase 2 Inhibitor Rofecoxib in Humans: Single and Multiple Oral Drug Administration

Cerebrospinal fluid (CSF) pharmacokinetics of orally administered cyclooxygenase 2 inhibitors, with single or multiple dosing, is of clinical relevance because it may relate to the analgesic efficacy of these drugs. We enrolled 9 subjects with implanted intrathecal catheters in the study. After 50-mg oral rofecoxib administration, the CSF drug concentration lagged slightly behind the plasma drug concentration. The ratio of the 24-h area under the drug-concentration curve (AUC) in CSF to plasma was 0.142. After daily dosing of rofecoxib 50 mg/d for 9 days, rofecoxib concentrations in plasma and CSF were larger on Day 9 than on Day 1, with the 24-h AUC on Day 9 more than twice the Day 1 AUC for both plasma and CSF. After nine consecutive daily doses of rofecoxib, the AUC(CSF)/AUC(plasma) ratio was 0.159. The important findings of this study are that CSF rofecoxib levels are approximately 15% of plasma levels and that repeated daily dosing more than doubles the AUC in CSF.

Anti-inflammatory drugs and tumor necrosis factor-alpha production from monocytes: role of transcription factor NF-kappa B and implication for rheumatoid arthritis therapy

Inhibition of tumor necrosis factor-alpha (TNF-alpha) represents a relevant target in rheumatoid arthritis therapy. Besides inhibiting cyclooxygenase, anti-inflammatory drugs can affect the activation of transcription factors. We investigated the ability of dexamethasone, indomethacin, and rofecoxib to modulate nuclear factor-kappaB (NF-kappaB) activation and TNF-alpha release from human monocytes challenged with lipopolysaccharide (LPS) or phorbol 12-myristate 13-acetate (PMA). Both stimuli induced NF-kappaB nuclear translocation and TNF-alpha secretion. Dexamethasone potently inhibited TNF-alpha release, indomethacin inhibited only PMA-evoked release, while rofecoxib had no effect. In the electrophoretic mobility shift assay, dexamethasone and rofecoxib dose-dependently inhibited the DNA binding activity of NF-kappaB in stimulated monocytes, whereas indomethacin failed to inhibit the LPS-evoked one. These results were further confirmed by evaluating the drugs' ability to reduce nuclear NF-kappaB subunits, as well as the amount of phosphorylated IkappaBalpha in cytosolic fractions. In conclusion, these results indicate that anti-inflammatory drugs differ largely in their ability to inhibit NF-kappaB activity and/or TNF-alpha release from human monocytes. These effects can be relevant to rheumatoid arthritis therapy.

The cyclooxygenase-2 pathway as a target for treatment or prevention of cancer

Cyclooxygenase (COX)-2, an inducible enzyme involved in prostaglandin biosynthesis, has attracted considerable attention recently, due to its role in human cancer biology. Several studies have correlated an increase in the expression of COX-2 with a poor clinical outcome, while epidemiological studies demonstrate a reduced risk of cancer mortality in persons with longterm, chronic ingestion of non-steroidal anti-inflammatory drugs (NSAIDs). Originally, these observations were made in patients with colorectal cancer, and subsequent studies suggest a protective role of NSAIDs in other human cancers as well. With the development of COX-2 specific inhibitors, numerous laboratory and clinical studies are underway to help understand the role of COX-2 in cancer and the potential use of COX-2 selective inhibitors for cancer treatment or prevention. This review focuses on the physiological function of COX, and the clinical rationale for evaluating COX-2 selective inhibitors for use in oncology.

Rofecoxib attenuates both primary and secondary inflammatory hyperalgesia: a randomized, double blinded, placebo controlled crossover trial in the UV-B pain model

The analysis of drug's influence on peripheral and central sensitisation can give useful information about its mode of action and can lead to more efficacy in the treatment of pain. Peripheral inflammation is associated with peripheral expression and up-regulation of cyclooxygenase 2 (COX-2) in the CNS. The relative contribution of COX-2 mediated central sensitisation may be prominent under inflammatory conditions. In this randomized, double blinded, placebo controlled cross-over trial the effects of multidoses of the COX-2 selective inhibitor rofecoxib on primary and secondary hyperalgesia were evaluated in the UVB pain model. Twenty-four hours after local UVB irradiation at the upper leg of 42 healthy volunteers heat pain perception (HPPT) and heat pain tolerance thresholds (HPTT) were assessed within the inflammation. The area of secondary hyperalgesia was determined by pin prick test. Subjects received oral rofecoxib 50, 250, 500 mg or placebo. Pain testing was repeated after 3 and 6 h. Compared to placebo, rofecoxib significantly increased HPPT (1.55 and 1.08 degrees C, P<0.0001 and P=0.0333), HPTT (1.74 and 1.58 degrees C, P<0.0001 and P<0.0001), and reduced the mean area of secondary hyperalgesia by 15.6% (P=0.007) and 16.8% (P<0.001) after 3 and 6 h. No significant difference between the three dosage groups was observed. These data confirm peripheral effects of rofecoxib in a human inflammatory UV-B pain model and provide circumstantial evidence that even a standard clinical dose of rofecoxib reduces central hyperalgesia in inflammatory pain. We confirm that the effect of single oral dose of rofecoxib plateaus at 50 mg.

Cyclo-Oxygenase-2 Inhibitors

The major goal of clinicians when treating acute musculoskeletal injuries is to return athletes to their pre-injury level of function, ideally in the shortest time possible and without compromising tissue-level healing. In this regard, a commonly used intervention is the taking of NSAIDs. These are used to limit the amount and duration of inflammation, and to control pain. While NSAIDs have become synonymous with the management of acute musculoskeletal injuries, their efficacy has yet to be proven. This is of particular concern in view of recent research investigating the latest class of NSAIDs - selective cyclo-oxygenase-2 inhibitors (COXIBs). COXIBs were developed to reduce the adverse gastrointestinal (GI) effects of traditional NSAIDs. While they have beneficial anti-inflammatory and analgesic properties, and appear to facilitate earlier return to function following acute injury, the effect of COXIBs on tissue-level healing is currently unknown. In experimental animal models of acute injury, COXIBs have been shown to be detrimental to tissue-level repair. Specifically, they have been shown to impair mechanical strength return following acute injury to bone, ligament and tendon. Clinically, this may have implications for ongoing morbidity and future injury susceptibility. However, the current animal studies have limited translation to the clinical setting, particularly because of significant limitations relating to drug use and dosage in these studies. There is currently no randomised, controlled trial evidence of the tissue-level effects of COXIBs on acute musculoskeletal injuries. In addition to questions relating to the effect of COXIBs on tissue-level healing, further questions regarding the use of these agents have been raised given a recent link being shown between one COXIB (rofecoxib) and an increased risk for adverse cardiovascular events. Whether this finding is related to the individual properties of rofecoxib or is a class phenomenon is the subject of ongoing investigation. However, in light of the potential risks associated with using COXIBs, an acceptable and possibly safer alternative in the management of acute musculoskeletal injuries may be to use traditional NSAIDs. Traditional NSAIDs do carry the potential for greater adverse GI effects and their clinical effects on tissue-level healing remain relatively unknown. However, they do not appear to be associated with adverse cardiovascular effects, and they are effective pain relievers and cheaper alternatives.

The upper gastrointestinal safety of rofecoxib vs. NSAIDs: an updated combined analysis

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAIDs) are nonspecific cyclo-oxygenase (COX-1/COX-2) inhibitors and are associated with gastrointestinal (GI) toxicity attributable to COX-1 inhibition. Rofecoxib, a COX-2 specific inhibitor, was developed to provide similar efficacy and less GI toxicity than NSAIDs.

OBJECTIVE

To update the results of a previously performed analysis of the incidence of upper GI perforations, symptomatic gastroduodenal ulcers, and upper GI bleeding (PUBs) with rofecoxib compared with non-selective NSAIDs.

RESEARCH DESIGN AND METHODS

We compared the incidence of PUBs in a combined analysis of 20 randomized, double-blind, clinical trials of rofecoxib versus NSAIDs. Men and women (N = 17,072) from multinational trial sites with osteoarthritis or rheumatoid arthritis were studied. There was no upper age limit in any of the trials. Investigator-reported PUBs were reviewed by a blinded, external adjudication committee using pre-specified criteria. The incidence of confirmed PUBs, the main outcome measure, among patients treated with rofecoxib 12.5 mg, 25 mg, or 50 mg (combined, N = 10 026) was compared to that among patients treated with ibuprofen, diclofenac, nabumetone, or naproxen (combined, N = 7046).

RESULTS

The incidence of PUBs over 24.8 months was significantly lower with rofecoxib vs. NSAIDs (cumulative incidence 1.6% vs. 3.1%, p < 0.001; rate/100 patient-years 0.74 vs. 1.87; relative risk 0.36, 95% CI 0.24, 0.54). Results of subgroup analyses and comparisons of rofecoxib with individual NSAID comparators were consistent with the primary result, as was an analysis in patients with no PUB risk factors.

DISCUSSION

The analysis demonstrated a consistently lower incidence of confirmed PUBs with rofecoxib than with NSAIDs over 24.8 months. These results confirm those of a previous smaller combined analysis of clinical trials with rofecoxib vs. non-selective NSAIDs in OA patients only, in which the risk reduction for confirmed PUBs was approximately 50%. In addition, this analysis demonstrated risk reductions with rofecoxib vs. NSAIDs in risk subgroups and in patients who did not have any known risk factors for PUBs consistent with the primary result. Some of the studies in this analysis required scheduled endoscopies. Asymptomatic upper GI ulcers or bleeding diagnosed during scheduled procedures were not included in the primary endpoint, which may have caused a bias against rofecoxib.

CONCLUSIONS

Treatment with rofecoxib was associated with a statistically significantly (p < 0.001) lower incidence of PUBs than was treatment with NSAIDs. The difference was maintained in subgroups of patients with risk factors, as well as in those with no risk factors, for PUBs.

Pharmacokinetics of Rofecoxib in Children With Sickle Cell Hemoglobinopathy

Rofecoxib is a selective cyclooxygenase-2 (COX-2) inhibitor approved for the treatment of pain and arthritis in adults. It is available as a suspension, but there are no published pediatric pharmacokinetic data. This study characterized the disposition of rofecoxib in children with sickle cell hemoglobinopathy in a single-oral-dose, intensive pharmacokinetic study. Eight subjects aged 3 to 14 years (mean 8.9 years, 5 boys and 3 girls) received a single oral dose of rofecoxib (1 mg/kg, maximum 50 mg) as a suspension. Blood samples were collected over 72 hours following drug administration and plasma was assayed for rofecoxib using high-performance liquid chromatography (HPLC). Pharmacokinetic parameters (peak concentration [Cmax], time to reach peak concentration [tmax], area under the curve [AUC], oral clearance [Cl/F], elimination half-life [t½]) were calculated using standard noncompartmental methods. The mean dose was 35.6 mg (range 15-50 mg). Cmax averaged 582 ± 129 ng/mL, with a median tmax of 4.0 hours. Secondary peaks were observed in two subjects. Two subjects were discharged at 12 hours, preventing characterization of elimination. In the remaining six subjects, Cl/F averaged 1.34 ± 0.32 mL/min/kg, with a t½ of 14.8 ± 4.5 hours. No significant adverse events were observed. The disposition of rofecoxib in children appears to be similar to that in adults, with comparable values for Cmax, tmax, t½, and Cl/F.

Comparison of rofecoxib and oxycodone plus acetaminophen in the treatment of acute pain: a randomized, double-blind, placebo-controlled study in patients with moderate to severe postoperative pain in the third molar extraction model

BACKGROUND

Opiates, acetaminophen, nonselective nonsteroidal anti-inflammatory drugs (NSAIDs), and cyclooxygenase-2-selective inhibitors such as rofecoxib are used in the treatment of acute pain because of their anti-inflammatory and/or analgesic properties. Rofecoxib has demonstrated an improved gastrointestinal safety profile compared with nonselective NSAIDs.

OBJECTIVE

The aim of this study was to compare the analgesic efficacy and tolerability profile of rofecoxib 50 mg with those of the centrally acting, nonsalicylate, opiate/nonopiate analgesic combination oxycodone/acetominophen 5/325 in patients with pain after dental surgery.

METHODS

In this randomized, double-blind, placebo- and active comparator-controlled study, patients experiencing moderate to severe postoperative pain after extraction of > or =2 third molars (including > or =1 mandibular impaction) received a single oral dose of rofecoxib 50 mg, oxycodone/acetaminophen 5/325 mg, or placebo. End points included total pain relief over 6 hours (TOPAR6, the primary end point) and 4 hours (TOPAR4), patient's global assessment of treatment at 6 hours (GLOBAL6) and 24 hours (GLOBAL24), summed pain intensity difference over 6 hours (SPID6), onset of analgesic effect (time to perceptible/meaningful pain relief, using a 2-stopwatch method), peak pain relief (PEAKPR), peak pain intensity difference (PEAKPID), and duration of analgesic effect (time to use of rescue analgesia).

RESULTS

Two hundred twelve patients (63% female, 37% male; 76% white, 24% other; mean [SD] age, 20.9 [4.4] years; age range, 16-41 years) were enrolled in the study and received a single oral dose of rofecoxib 50 mg (n = 90), oxycodone/acetaminophen 5/325 mg (n = 91), or placebo (n = 31). The analgesic effect of rofecoxib was significantly greater than that of oxycodone/acetaminophen at P < 0.001 for TOPAR6, TOPAR4, GLOBAL6, GLOBAL24, and SPID6; at P < 0.010 for PEAKPR and PEAKPID; and at P < 0.001 for median time to use of rescue analgesia. Significantly fewer patients in the rofecoxib group (72.2%) took rescue analgesia within 24 hours postdose compared with the oxycodone/acetaminophen group (94.5%; P < 0.001) and the placebo group (96.8%; P < 0.02). Both active treatments were similar with respect to onset of analgesic effect. Both were generally well tolerated; the overall incidence of adverse experiences in the rofecoxib, oxycodone/acetaminophen, and placebo groups was 51.1%, 64.8%, and 48.4%, respectively. Rofecoxib was associated with a significantly lower incidence of nausea (18.9% vs 39.6%; P < 0.001) and vomiting (6.7% vs 23.1%; P < 0.001) compared with oxycodone/acetaminophen.

CONCLUSIONS

In study patients with moderate to severe pain after dental surgery, rofecoxib 50 mg had a greater analgesic effect than oxycodone/acetaminophen 5/325 mg and was associated with less nausea and vomiting.

Do some inhibitors of COX-2 increase the risk of thromboembolic events?: Linking pharmacology with pharmacoepidemiology

Inhibitors of the cyclo-oxygenase (COX)-2 isoenzyme were developed with the expectation that their use would be accompanied by a reduction in adverse reactions thought to be mediated through COX-1 compared with conventional nonselective NSAIDs. However, the results of some clinical studies and other evidence have led to the hypothesis that use of COX-2 inhibitors may contribute to an increased risk of adverse thromboembolic (TE) events. In this review, we have evaluated the evidence from small-scale in vitro and in vivo pharmacological studies, clinical trials and large-scale pharmacoepidemiological studies and commented on the relationship between the pharmacological characteristics related to thromboembolic events and the clinical effects in large-scale clinical trials and pharmacoepidemiological studies. Overall, the pharmacological evidence suggests that a prothrombotic effect of COX-2 selective inhibitors is plausible. To date, despite the results from the Vioxx Gastrointestinal Outcome Research (VIGOR) study from which the clinical concern regarding cardiovascular TE risk arose, the published data from other randomised controlled trials (RCTs), retrospective observational studies and spontaneous reporting schemes provide a conflicting body of evidence on the TE risk with COX-2 inhibitors. Concerns that COX-2 inhibitors may be associated with prothrombotic effects remain and these need to be addressed in large scale, RCTs designed specifically to investigate the possibility of an excess of adverse cardiovascular outcomes in users of some or all selective COX-2 inhibitors, both with and without concomitant low-dose aspirin (acetylsalicylic acid). Consideration must also be given to other pathophysiological mechanisms for potential cardiovascular risk linked with inhibition of COX-2. In view of the evidence reviewed, it is recommended that selective COX-2 inhibitors should be prescribed with caution, only in patients with conditions for which these drugs have proven efficacy and with careful monitoring of outcomes and adverse events. This is particularly important in the elderly, in patients with cardiovascular/renal disease and in patients with other risk factors that might predispose them to adverse events.

Determination of rofecoxib in human plasma and breast milk by high-performance liquid chromatographic assay

A rapid and simple HPLC assay was developed for the determination of rofecoxib in human plasma and breast milk. After solid-phase extraction, rofecoxib was resolved on a C18 column and detected by UV detection at 272 nm. Standard curves were linear over the concentration range 10-2000 microg/L (r2 >0.99). Intra- and inter-day coefficients of variation for both matrices were <10% and the limit of quantification was around 10 microg/L.

Pharmacokinetics of rofecoxib: a specific cyclo-oxygenase-2 inhibitor

Rofecoxib is a commonly used specific cyclo-oxygenase-2 (COX-2) inhibitor. Rofecoxib has high bioavailability, poor aqueous solubility, an elimination half-life suitable for daily administration and a volume of distribution approximating body mass. Species-specific, predominantly hepatic, metabolism occurs, with novel enterohepatic circulation in rats and O-glucuronidation by uridine diphosphate-glucuronosyl transferase (UGT) 2B7 and 2B15 in human liver microsomes. Discrepancies in studies of postoperative analgesia can be putatively explained by known pharmacokinetics. Changes in rofecoxib disposition and pharmacokinetics are evident between races, in elderly patients, in patients with chronic renal insufficiency and in patients with mild to moderate hepatic impairment. Despite the selective action of COX-2 inhibitors, there remains the potential for significant drug interactions. Rofecoxib has been shown to have interactions with rifampicin (rifampin), warfarin, lithium and angiotensin converting enzyme (ACE) inhibitors and theophylline. COX-2 inhibitors represent a major therapeutic advance in terms of gastrointestinal safety; however, long-term safety in other organ systems and with concomitant drug administration still remain to be proven.

Pharmacological treatments for persistent non-malignant pain in older persons

Persistent non-malignant pain is common, often neglected and under-treated among older persons. Some older adults do not complain because they consider chronic pain to be a characteristic of normal aging. Physicians have concerns regarding adverse effects of pharmacological treatment. The model of the World Health Organization for treatment of cancer pain is generally accepted and also recommended for persistent non-cancer pain. Furthermore, non-pharmacological treatment should complement drug treatment whenever possible. An initial assessment and possible treatment of underlying causes of pain are pertinent. Modern pharmacological pain management is based on non-opioid and opioid analgesics. NSAIDs are among the most widely prescribed class of drugs in the world. The new cyclo-oxygenase-2 inhibitors such as celecoxib and rofecoxib offer an alternative for the treatment of mild-to-moderate pain in patients with a history of gastric ulcers or bleeding. Paracetamol (acetaminophen) is being used widely for the management of mild pain across all age groups as it has moderate adverse effects at therapeutic dosages. For moderate pain, a combination of non-opioid analgesics and opioid analgesics with moderate pain relief properties (e.g. oxycodone, codeine, tramadol and tilidine/naloxone) is recommended. For severe pain, a combination of non-opioid analgesics and opioid analgesics with strong pain relief properties (e.g. morphine, codeine) is recommended. The least toxic means of achieving systemic pain relief should be used. For continuous pain, sustained-release analgesic preparations are recommended. Drugs should be given on a fixed time schedule, and possible adverse effects and interactions should be carefully monitored. Adjuvant drugs, such as antidepressants or anticonvulsants, can be very effective especially in the treatment of certain types of pain, such as in diabetic neuropathy. Effective pain management should result in decreased pain, increased function and improvement in mood and sleep.

Cyclooxygenase-2 inhibitors decrease interleukin-1beta-stimulated prostaglandin E2 and IL-6 production by human gingival fibroblasts

BACKGROUND

Previous work showed that normal and aggressive periodontitis (AgP) gingival fibroblasts produce the bone-resorbing cytokine IL-6. PGE2 is important in regulating IL-6 production. Non-steroidal anti-inflammatory drugs inhibit PG synthesis via COX-1 and/or COX-2 isoenzymes and may inhibit periodontal destruction. COX-2 is induced after cellular activation (i.e., by inflammatory cytokines such as IL-1beta). Little is known about IL-1beta-stimulated AgP fibroblast IL-6 and PGE2 production and their regulation by COX inhibitors. The objective of this study was to determine the effects of COX-2 inhibitors on amounts of PGE2 and IL-6 made by IL-1beta-stimulated gingival fibroblasts.

METHODS

Gingival fibroblasts (2.5 x 10(4)) from healthy or severe periodontitis patients were cultured in serum-free medium, with or without IL-1beta (10(-11)M) for 24 hours, with or without the COX-1/2 inhibitor indomethacin or the selective COX-2 inhibitors NS-398, celecoxib, or rofecoxib. PGE2 and IL-6 in culture supernatants were determined by specific enzyme-linked immunosorbent assay (ELISA)s.

RESULTS

All of the COX inhibitors caused dose-dependent decreases in IL-1beta-stimulated PGE2, to a maximum of > 90% in all cell lines (P < or = 0.0001). The selective COX-2 inhibitors, but not indomethacin, caused partial (generally up to approximately 60%), dose-dependent decreases in IL-1beta-stimulated IL-6 in all cell lines (P < or = 0.003). When exogenous PGE2 was added concurrently with COX-2 inhibitors before addition of IL-1beta, IL-6 production returned to levels at or approaching that produced by cells exposed only to IL-1beta (P < or = 0.04).

CONCLUSION

The results suggest that COX-2 inhibition may be useful in helping to control fibroblast production of IL-6 in patients with severe periodontitis.

Solubility enhancement of Cox-2 inhibitors using various solvent systems

This study examined the solubility enhancement of 4 cox-2 inhibitors, celecoxib, rofecoxib, meloxicam, and nimesulide, using a series of pure solvents and solvent mixtures. Water, alcohols, glycols, glycerol, and polyethylene glycol 400 (PEG 400) were used as solvents and water-ethanol, glycerol-ethanol, and polyethylene glycol-ethanol were used as mixed-solvent systems. A pH-solubility profile of drugs was obtained in the pH range 7.0 to 10.9 using 0.05 M glycine-sodium hydroxide buffer solutions. Lower alcohols, higher glycols, and PEG 400 were found to be good solvents for these drugs. The aqueous solubility of celecoxib, rofecoxib, and nimesulide could be enhanced significantly by using ethanol as the second solvent. Among the mixed-solvent systems, PEG 400- ethanol system had highest solubilization potential. In the case of meloxicam and nimesulide, solubility increased significantly with increase in pH value. Physico-chemical properties of the solvent such as polarity, intermolecular interactions, and the ability of the solvent to form a hydrogen bond with the drug molecules were found to be the major factors involved in the dissolution of drugs by pure solvents. The greater the difference in the polarity of the 2 solvents in a given mixed solvent, the greater was the solubilization power. However, in a given mixed-solvent system, the solubilization power could not be related to the polarity of the drugs. Significance of the solubility data in relation to the development of formulations has also been discussed in this study.

Pharmacology and gastrointestinal safety of lumiracoxib, a novel cyclooxygenase-2 selective inhibitor: An integrated study

BACKGROUND AND AIMS

Lumiracoxib is a structurally novel, acidic selective inhibitor of cyclooxygenase (COX)-2. We coordinated existing methodologies in a single study to evaluate potency, selectivity, and effect on the human gastrointestinal tract.

METHODS

Twenty four healthy subjects (aged 18-45 years, 12 female) received high dose lumiracoxib (800 mg every day), standard dose naproxen (500 mg twice a day), or placebo for 8 days in a double-blind randomized crossover study. At the start and end of each dosing period, COX-2 selectivity was assessed by ex vivo serum thromboxane B(2) (COX-1) and lipopolysaccharide stimulated prostaglandin (PG) E(2) (COX-2), mucosal injury by endoscopy, and small and large bowel permeability by 0- to 5-hour and 5- to 24-hour (51)Cr-EDTA absorption. Plasma lumiracoxib was measured 2 hours after dosing on day 8 and vortex-stimulated ex vivo gastric mucosal PGE(2) synthesis at the end of each treatment period by enzyme immunoassay.

RESULTS

Lumiracoxib was well absorbed and demonstrated similar potency to naproxen as a COX-2 inhibitor (77% and 66% inhibition, respectively, vs. placebo), but it differed in being more selective (24% and 97% inhibition of thromboxane B(2) vs. placebo). Gastric PGE(2) was reduced by 69% by naproxen (P < 0.001 vs. placebo) and 29% by lumiracoxib (P < 0.01 vs. placebo and naproxen). No subjects developed gastroduodenal erosions on lumiracoxib (vs. 75% on naproxen and 12.5% on placebo). (51)Cr-EDTA absorption increased significantly with naproxen but not lumiracoxib.

CONCLUSIONS

Lumiracoxib is a potent selective inhibitor of COX-2 that causes little or no endoscopically detected stomach or duodenal injury or changes in bowel permeability.

The effect of the selective cyclooxygenase-2 inhibitor rofecoxib on human colorectal cancer liver metastases

BACKGROUND & AIMS

Cyclooxygenase-2 (COX-2) is a potential target for chemotherapy of colorectal cancer (CRC). We tested the antineoplastic activity of the selective COX-2 inhibitor rofecoxib on human CRC liver metastases by measuring surrogate markers of tumor growth and angiogenesis in a randomized, double-blind, placebo-controlled trial.

METHODS

Patients undergoing liver resection surgery for metastatic disease were randomized to receive rofecoxib 25 mg daily or placebo before surgery (duration, >14 days). The apoptosis index (AI; neocytokeratin 18), proliferation index (PI; Ki-67), and microvessel density (MVD; CD31) were measured in metastases by immunohistochemistry. The effect of rofecoxib on COX-2-positive HCA-7 human CRC cell PGE(2) synthesis, proliferation, and apoptosis in vitro was also investigated.

RESULTS

Patients who received rofecoxib (n = 23) and placebo (n = 21) were well matched regarding clinical and metastasis characteristics. The mean (range) duration of rofecoxib therapy was 26 (14-46) days. Rofecoxib-treated metastases had a 29% decrease in MVD (mean, 25.1 [SEM, 2.7] per hpf) compared with placebo-treated tissue (32.5 [SEM, 4.5] per hpf; P = 0.15). There was little difference in AI (rofecoxib mean, 2.03% [SEM, 0.43%] vs. placebo 1.39% [SEM, 0.39%]) or PI (rofecoxib 54.7% [SEM, 5.1%] vs. placebo 52.6% [SEM, 5.6%]). Rofecoxib-induced growth arrest and apoptosis of HCA-7 cells occurred only at concentrations (>10 micromol/L), which were significantly higher than the IC(50) for COX-2 inhibition.

CONCLUSIONS

Rofecoxib may negatively regulate angiogenesis in human CRC liver metastases. The absence of a significant, direct effect of rofecoxib on epithelial cells in liver metastases in vivo mirrors the lack of activity on human CRC cells at pharmacologically relevant concentrations in vitro.

Rofecoxib: an update on physicochemical, pharmaceutical, pharmacodynamic and pharmacokinetic aspects

Rofecoxib (MK-966) is a new generation non-steroidal anti-inflammatory agent (NSAID) that exhibits promising anti-inflammatory, analgesic and antipyretic activity. It selectively inhibits cyclooxygenase (COX)-2 isoenzyme in a dose-dependent manner in man. No significant inhibition of COX-1 is observed with rofecoxib up to doses of 1000 mg. The pharmacokinetics of rofecoxib has been found to be complex and variable. Mean oral bioavailability after single dose of rofecoxib (12.5, 25 or 50 mg) is 93% with t(max) varying widely between 2 and 9 h. It is highly plasma-protein bound and is metabolized primarily by cytosolic reductases to inactive metabolites. Rofecoxib is eliminated predominantly by hepatic metabolism with a terminal half-life of approximately 17 h during steady state. Various experimental models and clinical studies have demonstrated rofecoxib to be superior, or at least equivalent, in anti-inflammatory, analgesic and antipyretic efficacy to comparator nonselective NSAIDs in osteoarthritis, rheumatoid arthritis and other pain models. Emerging evidence suggests that rofecoxib may also find potential use as supportive therapy in various pathophysiologic conditions like Alzheimer's disease, and in various malignant tumours and polyps, where COX-2 is overly expressed. Rofecoxib is generally well-tolerated. Analysis of data pooled from several trials suggests that rofecoxib is associated with fewer incidences of clinically symptomatic gastrointestinal ulcers and ulcer complications vis-à-vis conventional NSAIDs. However, this gastropreserving effect may be negated by concurrent use of low-dose aspirin for cardiovascular risk reduction. Rofecoxib tends to show similar tolerability for renal and cardiothrombotic events as compared with nonnaproxen nonselective NSAIDs. No clinically significant drug interaction has been reported for rofecoxib except with diuretics, where it reverses their salt-wasting effect and thus can be clinically exploited in electrolyte-wasting disorders. There is only modest information about the physicochemical and pharmaceutical aspects of rofecoxib. Being poorly water soluble, its drug delivery has been improved using varied formulation approaches. Although it is stable in solid state, rofecoxib is photosensitive and base-sensitive in solution form with its degradation mechanistics elucidated. Analytical determinations of rofecoxib and its metabolites in biological fluids employing HPLC with varied types of detectors have been reported. Isolated studies have also been published on the chromatographic and spectrophotometric assay of rofecoxib and its degradants in bulk samples and pharmaceutical dosage forms. The current article provides an updated overview on the physicochemical, pharmaceutical, pharmacokinetic and pharmacodynamic vistas of rofecoxib.

Effects of renal insufficiency and hemodialysis on the pharmacokinetics of rofecoxib

Rofecoxib (VIOXX, Merck & Co., West Point, PA) is a COX-2-selective inhibitor that combines anti-inflammatory and analgesic efficacy with improved gastrointestinal (GI) safety. The present open-label study investigated the pharmacokinetics, safety, and tolerability of a single, oral dose of rofecoxib (50 mg) in patients with end-stage renal failure (creatinine clearance <5 mL/min/1.73 m(2)) requiring hemodialysis. Rofecoxib AUC(0-48 h), AUC(0- infinity), C(max), T(max), and t(1/2) obtained from renal failure patients on hemodialysis were not significantly different from those obtained from healthy subjects. With hemodialysis initiated 48 hours postdose, rofecoxib AUC(0-48 h) adjusted mean ratio (renal failure/healthy subjects) was 0.81, with a corresponding 90% confidence interval (CI; 0.66, 1.00). Hemodialysis per se had no clinically meaningful effect on rofecoxib pharmacokinetics: plasma rofecoxib concentration-time curves were virtually superimposable when hemodialysis was initiated at 4 or 48 hours following rofecoxib dosing, although mean rofecoxib C(max) was 18% lower during the former (325 versus 395 ng/mL; P = 0.014). Overall, rofecoxib was well tolerated in end-stage renal disease patients. In this study, end-stage renal disease and hemodialysis had little effect on rofecoxib pharmacokinetics. Although there are no clinical data to support the use of rofecoxib in patients with severe renal insufficiency (creatinine clearance, 5-30 mL/min/1.73 m(2)), these data suggest that dosage adjustment of rofecoxib is not needed for patients with impaired renal function.

Efficacy and safety of rofecoxib in patients with chronic low back pain: results from two 4-week, randomized, placebo-controlled, parallel-group, double-blind trials

STUDY DESIGN

Two replicate, 4-week, randomized, double-blind, placebo-controlled, trials of rofecoxib 25 and 50 mg versus placebo for chronic low back pain.

OBJECTIVES

To determine the efficacy and safety of two doses of rofecoxib compared to placebo in the treatment of chronic low back pain.

SUMMARY OF BACKGROUND DATA

Although nonsteroidal anti-inflammatory drugs are commonly prescribed for chronic low back pain, their efficacy is unproven and toxicity can be serious. These studies evaluated the efficacy and tolerability of rofecoxib, a selective COX-2 inhibitor, in the treatment of chronic low back pain.

METHODS

Patients with chronic low back pain were randomized 1:1:1 to rofecoxib 25 mg, 50 mg, or placebo once daily. Primary endpoint: Low Back Pain Intensity. Secondary endpoints: Pain Bothersomeness, Global Assessments of Response to Therapy, Global Assessment of Disease Status, Roland-Morris Disability Questionnaire, SF-12 Health Survey, Use of Rescue Acetaminophen, and Discontinuations Due to Lack of Efficacy.

RESULTS

Combining both studies, 690 patients were randomized to placebo (N = 228), rofecoxib 25 mg (N = 233), or rofecoxib 50 mg (N = 229). Mean (+/- SD) age was 53.4 (+/- 12.9) years, pain duration 12.1 (+/- 11.8) years, 62.3% female. Both rofecoxib groups improved significantly. Mean differences from placebo in pain intensity were -13.50 mm, -13.81 mm (25, 50 mg doses) respectively (P < 0.001). Both regimens were superior to placebo in eight of nine secondary endpoints. Fifty mg provided no advantage over 25 mg. Both rofecoxib regimens were well tolerated, although 25 mg had a slightly better safety profile.

CONCLUSIONS

Rofecoxib significantly reduced chronic low back pain in adults and was well tolerated.

Selective inhibitors of cyclooxygenase-2 delay the activation of nuclear factor kappa B and attenuate the expression of inflammatory genes in murine macrophages treated with lipopolysaccharide

The effect of rofecoxib, a selective cyclooxygenase-2 inhibitor, on inflammatory signaling has been investigated in elicited murine peritoneal macrophages. Macrophages treated with 10 microM rofecoxib exhibited an important inhibition in the early activation of nuclear factor kappa B (NF-kappa B) and the mitogen-activated protein kinase p38, the extracellular-regulated kinase p44, and the c-Jun N-terminal kinase. Moreover, this drug decreased the protein levels of nitric-oxide synthase-2 and cyclooxygenase-2 in lipopolysaccharide (LPS)-treated macrophages. Rofecoxib delayed and attenuated NF-kappa B activation, which impaired significantly the expression of kappa B-dependent genes. This drug and related coxibs did not affect cell viability and protected against LPS-induced apoptosis through the impairment of the inflammatory response. These data show an additional anti-inflammatory mechanism of selective cyclooxygenase-2 inhibitors through the attenuation of macrophage activation.

[Clinical trials with rofecoxib: analysis of the information from the gender perspective]

BACKGROUND AND OBJECTIVE

There is evidence if the low rate of participation or even exclusion of women in clinical trials (CT), and that sex-differences are not considered in the design and analysis of the CT. The objectives of the study were to determine whether women are properly represented in the CT with rofecoxib and to analyze the information of CT with rofecoxib from a gender perspective.

MATERIAL AND METHOD

Twenty eight rofecoxib CT in adults have been reviewed, all indexed in Medline and published between 1999-2001. The FDA Guideline for the Study and Evaluation of Gender Differences in the Clinical Evaluation Drugs was used to analyze the information.

RESULTS

An 80% of the trials do not describe efficacy results by sex, and only one reports side effects by sex. A 78.3% does not report stratified analysis by sex. In the discussion the possible difference by sex of the results is mentioned in 3 occasions. Only 8% of the CT considers the influence of hormonal variation in the results. The pharmacokinetics issues related specifically to women are poorly followed: in 60% of the CT it is not specified the influence of oral contraceptives in the results of the trial, and in 88.9% of CT it is not specified the influence of estrogen treatment in the results of the trial. Pregnancy as exclusion criteria is only considered in 50% of the trials.

CONCLUSIONS

CT with rofecoxib has included more women than men. Important information on specific situation related to gender, recommends by FDA Guideline for the Study and Evaluation of Gender Differences in the Clinical Evaluation Drugs, have not been followed.

In vitro study of tocolytic effect of rofecoxib, a specific cyclo-oxygenase 2 inhibitor. Comparison and combination with other tocolytic agents

OBJECTIVE

The aim of this work was to study and compare the tocolytic effects of rofecoxib with indomethacin, ritodrine, nicardipine and atosiban. We also studied the combination of rofecoxib with each agent.

DESIGN

In vitro animal experimental study.

SETTING

Non-selective cyclo-oxygenase (COX) inhibitors have potent tocolytic effect. However, they also have major fetal side effects that seem to be due to COX-1 inhibition. A specific COX-2 inhibitor could be a potent tocolytic agent with less fetal toxicity.

SAMPLE

Myometrial strips from pregnant Wistar rats at 18 days of gestation.

METHODS

Isometric tension was recorded from 112 pregnant rat myometrial strips in vitro. Strips were exposed to increase molar concentration of one drug or combination.

MAIN OUTCOME MEASURES

Contractile activity was assessed by calculating the area under the curve, to obtain a dose-response curve of each drug. EC50 and mean maximal inhibiting concentration were compared using ANOVA. Chemical interaction was defined for each combination.

RESULTS

The in vitro tocolytic effect of rofecoxib was demonstrated. Contractile activity stopped at a concentration of 1.6 x 10(-7) M. Effective concentrations were 1000 times less than for indomethacin and significantly lower than ritodrine and atosiban. Rofecoxib combined with ritodrine had a synergic effect. Other combinations only had an additive effect.

CONCLUSIONS

Rofecoxib has a potent tocolytic effect in vitro. The high specificity and low effective concentrations of COX-2 may result in low fetal toxicity. Animal fetal side effects need to be explored.

The role of rofecoxib, a cyclooxygenase-2-specific inhibitor, for the treatment of non-cancer pain: A review

Rofecoxib was the first specific inhibitor of cyclooxygenase-2 (COX-2) approved for the treatment of acute pain. It has been shown to provide analgesia that is significantly better than placebo and has an onset of action and efficacy similar to that of traditional nonselective nonsteroidal anti-inflammatory drugs (NSAIDs), such as naproxen and ibuprofen. In addition, the analgesic efficacy of rofecoxib has been demonstrated to be superior to that of the opioid combination of codeine 60 mg/acetaminophen 600 mg in an acute dental pain model. For the treatment of acute pain, the efficacy of rofecoxib was further demonstrated in a study of patients who had undergone orthopedic surgery. Rofecoxib has been found to be as effective as naproxen sodium and more effective than placebo in studies evaluating its use for the treatment of primary dysmenorrhea. In patients with osteoarthritis (OA) of the knee or hip, rofecoxib is superior to placebo and similar to diclofenac and ibuprofen in relieving OA pain and improving physical function. Rofecoxib has also been shown to be superior to acetaminophen and celecoxib after 6 weeks of treatment for OA. The efficacy of rofecoxib has also been demonstrated in patients with rheumatoid arthritis and low back pain. The advantages of using COX-2-specific NSAIDs include convenient once-daily dosing schedule and improved safety compared with traditional NSAIDs. Two large outcomes studies, VIGOR and CLASS, have shown that gastric mucosal ulceration occurs significantly less often in patients taking COX-2-specific inhibitors than in those treated with ibuprofen, diclofenac, or naproxen and occurs with a similar incidence to that of placebo. Absence of any effect on platelet aggregation and bleeding time further distinguishes these agents from traditional NSAIDs. Because COX-2-specific inhibitors do not have an antiplatelet effect, they cannot be used as a substitute for low-dose aspirin for cardiovascular prophylaxis. Rofecoxib is a safe and highly effective alternative to previously available NSAIDs and should be considered for the treatment of acute pain conditions in adult patients, especially those at risk for developing gastrointestinal complications. It is preferred in the perioperative setting because of its analgesic efficacy and lack of platelet effects. Because of its more favorable gastrointestinal toxicity profile compared with nonselective NSAIDs, rofecoxib is safer in patients, especially older patients, for whom chronic anti-inflammatory or analgesic therapy is indicated.