Lack of pharmacokinetic interaction between rofecoxib and methotrexate in rheumatoid arthritis patients

A critical review of methotrexate clinical interactions: role of transporters

INTRODUCTION

Methotrexate (MTX) is an anti-folate and immunosuppressive drug prescribed for various malignancies and immune diseases. However, delayed elimination of MTX associated with concomitant use of some medications can lead to severe and life-threatening adverse effects.

AREAS COVERED

This paper investigated drug-MTX interactions that lead to elevated MTX levels and related adverse effects due to the role of transporters. Methotrexate toxicity occurs at both low and high doses administrations. According to the studies we reviewed in this paper, most interaction records with methotrexate occurred with co-administration of indomethacin, ketoprofen, omeprazole, piperacillin/tazobactam, ciprofloxacin, co-trimoxazole, probenecid, and imatinib, mainly due to the role of transporters. However, most studies were performed as case reports or series, and confirming the exact drug-methotrexate interaction still needs further clinical investigations.

EXPERT OPINION

Our findings showed no firm evidence of interactions of proton pump inhibitors (PPIs), levetiracetam, and NSAIDS with MTX. Moreover, patients' risk factors, hypoalbuminemia, renal failure, third space fluid retention, the elderly, polypharmacy, and transport inhibition are the most critical factors for MTX toxicity. If substitution or temporary discontinuation is not possible, healthcare providers should be aware of interactions, especially in patients with risk factors for MTX toxicity.

Interaction Between Low-Dose Methotrexate and Nonsteroidal Anti-inflammatory Drugs, Penicillins, and Proton Pump Inhibitors

Objective: To review the potential drug interactions between low-dose methotrexate (LD-MTX) and nonsteroidal anti-inflammatory drugs (NSAIDs), penicillins, and proton-pump inhibitors (PPIs) given the disparity between interactions reported for high-dose and low-dose MTX to help guide clinicians. Data Sources: A literature search was performed in MEDLINE (1946 to September 2016), EMBASE (1974 to September 2016), and International Pharmaceutical Abstracts (1970 to January 2015) to identify reports describing potential drug interactions between LD-MTX and NSAIDS, penicillins, or PPIs. Reference lists of included articles were reviewed to find additional eligible articles. Study Selection and Data Extraction: All English-language observational, randomized, and pharmacokinetic (PK) studies assessing LD-MTX interactions in humans were analyzed to determine clinical relevance in making recommendations to clinicians. Clinical case reports were assigned a Drug Interaction Probability Scale score. Data Synthesis: A total of 32 articles were included (28 with NSAIDs, 3 with penicillins, and 2 with PPIs [1 including both PPI and NSAID]). Although there are some PK data to describe increased LD-MTX concentrations when NSAIDs are used concomitantly, the clinical relevance remains unclear. Based on the limited data on LD-MTX with penicillins and PPIs, no clinically meaningful interaction was identified. Conclusion: Given the available evidence, the clinical importance of the interaction between LD-MTX and NSAIDs, penicillins, and PPIs cannot be substantiated. Health care providers should assess the benefit and risk of LD-MTX regardless of concomitant drug use, including factors known to predispose patients to MTX toxicity, and continue to monitor clinical and laboratory parameters per guideline recommendations.

Coadministration of Lansoprazole and Naproxen Does Not Affect the Pharmacokinetic Profile of Methotrexate in Adult Patients With Rheumatoid Arthritis

Drugs prescribed for rheumatoid arthritis are often associated with gastrointestinal toxicity, and proton pump inhibitors may be coadministered for gastroprotection. In this open-label study, the effect of lansoprazole 30 mg qd and naproxen 500 mg bid on the pharmacokinetic profile of methotrexate was investigated. Twenty-seven adult rheumatoid arthritis patients on stable oral methotrexate doses (7.5-15 mg/week) for a minimum of 3 months were enrolled. Methotrexate pharmacokinetics were assessed on days -1 (methotrexate alone) and 7 (methotrexate with lansoprazole and naproxen). Pharmacokinetics of methotrexate and 7-hydroxymethotrexate were not altered by coadministration of methotrexate with lansoprazole and naproxen; point estimates and 90% confidence intervals for the peak plasma concentration and area under the plasma concentration-time curve of methotrexate and 7-hydroxymethotrexate were within the 0.80 to 1.25 boundaries. Therefore, coadministration of naproxen and lansoprazole for 7 days does not affect the pharmacokinetic profile of low doses of methotrexate.

A randomized, double-blind, parallel, single-site pilot trial to compare two different starting doses of methotrexate in methotrexate-naïve adult patients with rheumatoid arthritis

BACKGROUND

Methotrexate (MTX) is a cornerstone in the treatment of rheumatoid arthritis. Despite its widespread use, expert opinions differ about the optimal MTX starting dosage to achieve rapid onset of action while averting increased occurrence of adverse effects. Plasma concentrations have not been assessed in previous studies that monitored clinical efficacy.

OBJECTIVE

This study was performed to compare the pharmacokinetic parameters and clinical response of a standard (15 mg) and an accelerated (25 mg) dosing regimen, each administered orally once a week.

METHODS

This randomized, controlled, double-blind, parallel, single-site study included 19 MTX-naïve patients older than 18 years with rheumatoid arthritis. Patients participated for 16 weeks. Disease activity was assessed using the Disease Activity Score in 28 joints (DAS-28) as the primary outcome parameter. Plasma MTX concentrations were measured using HPLC at weeks 1, 5, 10, and 16. Tolerability was assessed via routine blood analysis (hematology and clinical chemistry) and a patient questionnaire to monitor adverse events. Reported or observed adverse events were recorded along with information about their severity and causal relationship to the study medication.

RESULTS

Nineteen white patients (13 women and 6 men; mean age, 56 years; and mean weight, 74 kg) participated. At study entry, mean (SD) DAS-28-4v (erythrocyte sedimentation rate) was 4.73 (1.02). Health Assessment Questionnaire scores were 1.45 (0.85); for C-reactive protein, 11.45 (10.04) mg/dL; for alkaline phosphatase, 73.58 (19.91) U/L; for aspartate aminotransferase, 23.32 (7.13) U/L; and for creatinine, 0.87 (0.22) mg/dL. Although pharmacokinetic parameters such as AUC and C(max) were significantly higher after the accelerated dosing regimen, clinical activity scores (DAS-28) and inflammation parameters (C-reactive protein) did not indicate a significant benefit of an accelerated starting regimen. Considering toxicity, no elevation in liver function enzymes and no decrease in renal function were observed using the accelerated dosing (statistical significance set at P ≤ 0.05). No serious adverse events were noted. All observed adverse events were classified as study related. Overall, adverse events were noted in 58% of patients. Comparison of the two doses revealed that 60% of patients receiving the standard dosing regimen and 56% of patients receiving the accelerated dosing regimen reported adverse events, the most frequent being gastrointestinal. These events were generally self-limiting.

CONCLUSIONS

Differences in clinical response between these two small selected patient groups who received an initial oral dose of either 15 or 25 mg MTX per week did not reach the level of statistical significance. The overall incidence of adverse effects, all classified as study related, was 58%, with 60% of patients receiving the standard dosage and 56% of patients receiving the accelerated dosing regimen reporting adverse effects. However, because of the small sample size, this study was not powered to detect differences in the incidence of adverse events between the two dosing groups. ClinicalTrials.gov identifier: NCT00695188.

Safety of non-steroidal anti-inflammatory drugs, including aspirin and paracetamol (acetaminophen) in people receiving methotrexate for inflammatory arthritis (rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, other spondyloarthritis)

BACKGROUND

Methotrexate is routinely used in the treatment of inflammatory arthritis. There have been concerns regarding the safety of using concurrent non-steroidal anti-inflammatory drugs (NSAIDs), including aspirin, or paracetamol (acetaminophen), or both, in these people.

OBJECTIVES

To systematically appraise and summarise the scientific evidence on the safety of using NSAIDs, including aspirin, or paracetamol, or both, with methotrexate in inflammatory arthritis; and to identify gaps in the current evidence, assess the implications of those gaps and to make recommendations for future research to address these deficiencies.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, second quarter 2010); MEDLINE (from 1950); EMBASE (from 1980); the Cochrane Database of Systematic Reviews (CDSR) and the Database of Abstracts of Reviews of Effects (DARE). We also handsearched the conference proceedings for the American College of Rheumatology (ACR) and European League against Rheumatism (EULAR) (2008 to 2009) and checked the websites of regulatory agencies for reported adverse events, labels and warnings.

SELECTION CRITERIA

Randomised controlled trials and non-randomised studies comparing the safety of methotrexate alone to methotrexate with concurrent NSAIDs, including aspirin, or paracetamol, or both, in people with inflammatory arthritis.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the search results, extracted data and assessed the risk of bias of the included studies.

MAIN RESULTS

Seventeen publications out of 8681 identified studies were included in the review, all of which included people with rheumatoid arthritis using various NSAIDs, including aspirin. There were no identified studies for other forms of inflammatory arthritis.For NSAIDs, 13 studies were included that used concurrent NSAIDs, of which nine studies examined unspecified NSAIDs. The mean number of participants was 150.4 (range 19 to 315), mean duration 2182.9 (range 183 to 5490) days, although the study duration was not always clearly defined, and the studies were mainly of low to moderate quality. Two of these studies reported no evidence for increased risk of methotrexate-induced pulmonary disease; one study assessed the effect of concurrent NSAIDs on renal function and found no adverse effect; one study identified no adverse effect on liver function; three studies demonstrated no increase in methotrexate withdrawal; and one study showed no increase in all adverse events, including major toxic reactions. However, transient thrombocytopenia was demonstrated in one study, specifically when NSAIDs were taken on the same week day as methotrexate. This study was a retrospective review that involved small numbers only and was of moderate quality; these finding have not been replicated since.Four studies looked at specific NSAIDs (etodolac, piroxicam, celecoxib and etoricoxib), with a mean number of participants of 25.8 (range 14 to 50) and mean study duration of 16.8 (range 14 to 23) days. These studies were mainly of moderate quality. The studies were primarily pharmacokinetic studies but also reported adverse events as secondary outcomes. There were no clinically significant adverse effects with concomitant piroxicam or etodolac; and only mild adverse events with celecoxib or etoricoxib, such as nausea and vomiting, and headaches.For aspirin, seven studies provided data on adverse events with the use of aspirin and methotrexate. These studies included a mean number of participants of 100 (range 11 to 232), had a mean duration of 1325 (range 8 to 2928) days and were mainly of low to moderate quality. Two of the studies reported no evidence for increased risk of methotrexate-induced pulmonary disease and two studies showed no increase in all adverse events including major toxic reactions; however, none of these studies specified the dose of aspirin that was used. One study demonstrated that concurrent aspirin adversely affected liver function at a mean dose of 6.84 tablets of aspirin per day, which is a possible daily dose of 2.1 g presuming that 300 mg aspirin tablets were given. A further study described a partially reversible decline in renal function with 2 g daily of aspirin. One study reported no increase in adverse events with 975 g aspirin daily, however the study duration was only one week.For paracetamol, no studies were identified for inclusion.

AUTHORS' CONCLUSIONS

In the management of rheumatoid arthritis, the concurrent use of NSAIDs with methotrexate appears to be safe provided appropriate monitoring is performed. The use of anti-inflammatory doses of aspirin should be avoided.

Fostamatinib, a Syk-kinase inhibitor, does not affect methotrexate pharmacokinetics in patients with rheumatoid arthritis

Fostamatinib (R788) is being investigated as an add-on therapy for the treatment of rheumatoid arthritis (RA) in patients with inadequate response to methotrexate (MTX). This study evaluated the potential pharmacokinetic interaction between R788 and MTX. Sixteen RA subjects on a stable weekly MTX regimen were enrolled and received MTX on days 1 and 8. Twelve subjects received 100 mg of R788 orally, and 4 subjects received a matching placebo twice daily from days 4 to 8 and once daily on days 3 and 9. Blood samples were collected on days 1 and 8 for MTX and 7-hydroxymethotrexate (7-OH-MTX), and days 3 and 9 for R788 and its active metabolite, R406. MTX and 7-OH-MTX pharmacokinetic parameters were similar on days 1 and 8. In the R788 group, the mean day 8 to day 1 ratios (90% confidence intervals) of maximum concentration and area under the plasma concentration-time curve estimates were 1.01 (0.85-1.20) and 1.12 (0.90-1.40) for MTX and 1.06 (0.82-1.35) and 1.06 (0.83-1.36) for 7-OH-MTX, respectively. Urinary excretion of MTX and 7-OH-MTX was also similar with or without R788, averaging 58% to 69% and 4% to 5% of the MTX dose, respectively. The data suggest that there is no clinically significant pharmacokinetic interaction of R788 and MTX in RA patients.

Canadian recommendations for use of methotrexate in patients with rheumatoid arthritis

OBJECTIVE

To develop recommendations for the use of methotrexate (MTX) in patients with rheumatoid arthritis.

METHODS

Canadian rheumatologists who participated in the international 3e Initiative in Rheumatology (evidence, expertise, exchange) in 2007-2008 formulated 5 unique Canadian questions. A bibliographic team systematically reviewed the relevant literature on these 5 topics. An expert committee consisting of 26 rheumatologists from across Canada was convened, and a set of recommendations was proposed based on the results of systematic reviews combined with expert opinions using a nominal group consensus process.

RESULTS

The 5 questions addressed drug interactions, predictors of response, strategies to reduce non-serious side effects, variables to assess clinical response, and incorporating patient preference into decision-making. The systematic review retrieved 93 pertinent articles; this evidence was presented to the expert committee during the interactive workshop. After extensive discussion and voting, a total of 9 recommendations were formulated: 2 on drug interactions, 1 on predictors of response, 2 on strategies to reduce non-serious side effects, 3 on variables to assess clinical response, and 1 on incorporating patient preferences into decision-making. The level of evidence and the strength of recommendations are reported. Agreement among panelists ranged from 85% to 100%.

CONCLUSION

Nine recommendations pertaining to the use of MTX in daily practice were developed using an evidence-based approach followed by expert/physician consensus with high level of agreement.

Methotrexate drug interactions in the treatment of rheumatoid arthritis: a systematic review

OBJECTIVE

Patients with rheumatoid arthritis (RA) often have comorbidities that require multiple medications. Several of these medications may alter the efficacy or increase the toxicity of methotrexate (MTX). The purpose of our study was to determine which drugs used in combination with MTX (excluding disease modifying antirheumatic drugs, folic and folinic acid, corticosteroids, and biologic agents) enhance side effects or toxicity of MTX or lower its efficacy.

METHODS

A systematic literature search was performed with Medline, Embase, Cochrane Register and Database, and abstracts from the 2006/2007 annual congresses of the American College of Rheumatology and the European League Against Rheumatism. A manual search of the citation lists of retrieved publications was performed.

RESULTS

Of the 1172 articles identified, 67 were included: 21 pharmacokinetics studies, 5 observational studies, and 78 case reports. Most medications do not significantly affect the pharmacokinetics profile of MTX. Among the clinical studies, cytopenia and elevation of liver enzymes were the main reported toxicities. The use of trimethoprim-sulfamethoxazole (TMP-SMX) was mentioned as a risk factor for developing cytopenia in one observational study and in 17 case reports. Thirty case reports of cytopenia were attributed to the use of concomitant nonsteroidal antiinflammatory drugs, including acetylsalicylic acid. Two studies described mild abnormalities of liver enzymes with the use of isoniazid, and one study with the use of high-dose ASA.

CONCLUSION

Based on the published literature, MTX has limited drug interactions, with the exception of TMP-SMX and high-dose ASA, which can exacerbate toxicity of MTX. The clinical significance of these interactions has not been substantiated by extensive clinical observations.

A proof-of-concept and drug-drug interaction study of pamapimod, a novel p38 MAP kinase inhibitor, with methotrexate in patients with rheumatoid arthritis

This study evaluated the potential pharmacokinetic interaction of pamapimod, a p38 mitogen-activated protein kinase inhibitor, and methotrexate (MTX) when administered concomitantly in patients with rheumatoid arthritis (RA); the study also evaluated the pharmacodynamic effects of pamapimod. Twenty-two RA patients on a stable regimen of MTX (10-25 mg/wk; administered on days 1 and 8) were randomized to receive 300 mg of pamapimod (n = 17) or placebo (n = 5) once daily (qd) for 10 days (days 5-14). Blood and urine samples were collected pre- and postdose on days 1 (MTX alone), 7 (pamapimod alone), and 8 (MTX and pamapimod coadministered). No clinically significant changes were observed in plasma exposures and renal clearance of pamapimod, MTX, or their metabolites, whether administered separately or concomitantly. The combination of pamapimod (300 mg qd) for 10 days and weekly MTX was generally well tolerated. Parameters of RA disease--namely, tender joint count, swollen joint count, erythrocyte sedimentation rate, and C-reactive protein--generally decreased between days 5 and 14. The results of this study suggest that dose adjustments for either drug are not necessary when concomitantly administered and that pamapimod can decrease pharmacodynamic markers of disease activity.

Guidelines of care for the management of psoriasis and psoriatic arthritis: section 4. Guidelines of care for the management and treatment of psoriasis with traditional systemic agents

Psoriasis is a common, chronic, inflammatory, multisystem disease with predominantly skin and joint manifestations affecting approximately 2% of the population. In this fourth of 6 sections of the guidelines of care for psoriasis, we discuss the use of traditional systemic medications for the treatment of patients with psoriasis. Treatment should be tailored to meet individual patients' needs. We will discuss in detail the efficacy and safety, and offer recommendations for the use of the 3 most commonly used, and approved, traditional systemic agents: methotrexate, cyclosporine, and acitretin. We will also briefly discuss the available data for the use of azathioprine, fumaric acid esters, hydroxyurea, leflunomide, mycophenolate mofetil, sulfasalazine, tacrolimus, and 6-thioguanine in psoriasis.

Methotrexate and psoriasis: 2009 National Psoriasis Foundation Consensus Conference

BACKGROUND

Methotrexate remains a valuable option for the treatment of psoriasis. This report will summarize studies regarding the use of methotrexate since the last guidelines were published in 1998.

OBJECTIVE

A task force of the National Psoriasis Foundation Medical Board was convened to evaluate treatment options. Our aim was to achieve a consensus on new updated guidelines for the use of methotrexate in the treatment of psoriasis.

METHODS

Reports in the literature were reviewed regarding methotrexate therapy.

RESULTS

A consensus was achieved on use of methotrexate in psoriasis including specific recommendations on dosing and monitoring. The consensus received unanimous approval from members of the Medical Board of the National Psoriasis Foundation.

LIMITATIONS

There are few evidence-based studies on the treatment of psoriasis with methotrexate. Many of the reviewed reports are for the treatment of rheumatoid arthritis.

CONCLUSIONS

Methotrexate is a safe and effective drug for the treatment of psoriasis. Appropriate patient selection and monitoring will significantly decrease the risks of side effects. In patients without risk factors for hepatic fibrosis, liver biopsies may not be indicated or the frequency of liver biopsies may be markedly reduced.

Clinically Significant Drug–Drug Interactions Between Oral Anticancer Agents and Nonanticancer Agents: Profiling and Comparison of Two Drug Compendia

Background:

Use of oral anticancer agents is gaining wide acceptance in the treatment of cancer. However, patients receiving oral therapy are at high risk for drug–drug interactions (DDIs).

Objective:

To create a drug profile for each clinically significant DDI involving selected oral anticancer agents and evaluate the agreement between 2 commonly used DDI compendia: Drug Interaction Facts (DIF) 2008 and Micromedex DRUGDEX.

Methods:

DDI profiles were developed based on primary and tertiary literature reviews. DIF 2008 and Micromedex DRUGDEX were compared to assess the consistency of listings, severity, and scientific evidence ratings of DDIs involving the oral anticancer agents that were selected. The Spearman correlation test was used to assess the correlation of the severity ratings between the 2 compendia.

Results:

A total of 184 DDIs were identified. A DDI profile was created for 40 of these that met the predetermined criteria for clinically significant interactions. The comparative assessment showed inconsistency in DDI listings (15.2% of those identified were listed in DIF only and 46.7% were listed in Micromedex only), severity ratings (Spearman correlation coefficient 0.49), and scientific evidence ratings (disagreement 25.8%).

Conclusions:

The discrepancies in DDI listing and rating systems between the compendia evaluated here reflect the need for more studies to standardize the definitions and classifications of DDIs.

Interaction of Nonsteroidal Anti-Inflammatory Drugs with Multidrug Resistance Protein (MRP) 2/ABCC2- and MRP4/ABCC4-Mediated Methotrexate Transport

Methotrexate (MTX) has been used in combination with nonsteroidal anti-inflammatory drugs (NSAIDs) in the treatment of inflammatory diseases as well as malignancies. Especially at high MTX dosages, severe adverse effects with this combination may occur, usually resulting from an impaired renal elimination. It has been shown that the mechanism of this interaction cannot be fully attributed to inhibition of basolateral MTX uptake in renal proximal tubules. Here, we studied the effect of various NSAIDs on MTX transport in membrane vesicles isolated from cells overexpressing the proximal tubular apical efflux transporters human multidrug resistance protein (MRP) 2/ABCC2 and MRP4/ABCC4. MTX was transported by MRP2 and MRP4 with Km values of 480 +/- 90 and 220 +/- 70 microM, respectively. The inhibitory potency of the NSAIDs was generally higher against MRP4- than MRP2-mediated MTX transport, with therapeutically relevant IC50 values, ranging from approximately 2 microM to 1.8 mM. Salicylate, piroxicam, ibuprofen, naproxen, sulindac, tolmetin, and etodolac inhibited MRP2- and MRP4-mediated MTX transport according to a one-site competition model. In some cases, more complex interaction patterns were observed. Inhibition of MRP4 by diclofenac and MRP2 by indomethacin and ketoprofen followed a two-site competition model. Phenylbutazone stimulated MRP2 and celecoxib MRP4 transport at low concentrations and inhibited both transporters at high concentration. Our data suggest that the inhibition by NSAIDs of renal MTX efflux via MRP2 and MRP4 is a potential new site and mechanism contributing to the overall interaction between these drugs.

Clinical utility and pharmacology of high-dose methotrexate in the treatment of primary CNS lymphoma

Primary CNS non-Hodgkin lymphoma (PCNSL) has been shown to be increasing in incidence. This appears to be a consequence of the increasing population of those older than 65 years of age in whom PCNSL occurs most often. PCNSL often has a favorable response to treatment and aggressive management may result in extended survival and, in a proportion of patients less than 65 years of age, cure. The majority of neuro-oncologist's advocate utilizing high-dose methotrexate (HD-MTX) as a platform for the chemotherapy treatment of these neoplasms. In this review, the literature regarding HDHMTX as a treatment for PCNSL is summarized as are the pharmacological principles of HD-MTX.

Two Drug Interaction Studies Evaluating the Pharmacokinetics and Toxicity of Pemetrexed When Coadministered with Aspirin or Ibuprofen in Patients with Advanced Cancer

PURPOSE

Pemetrexed is an antimetabolite that is structurally similar to methotrexate. Because nonsteroidal anti-inflammatory drugs (NSAID) impair methotrexate clearance and increase its toxicity, we evaluated the pharmacokinetics and toxicity of pemetrexed when coadministered with aspirin or ibuprofen in advanced cancer patients.

EXPERIMENTAL DESIGN

In two independent, randomized, crossover drug interaction studies, cancer patients with a creatinine clearance (CrCl) > or =60 mL/min received an NSAID (aspirin or ibuprofen) with either the first or the second dose of pemetrexed (cycle 1 or 2). Pemetrexed (500 mg/m(2)) was infused i.v. on day 1 of a 21-day cycle, and all patients were supplemented with oral folic acid and i.m. vitamin B(12). Aspirin (325 mg) or ibuprofen (400 mg; 2 x 200 mg) was given orally every 6 hours, starting 2 days before pemetrexed administration, with the ninth and final dose taken 1 hour before infusion. Pemetrexed pharmacokinetics with and without concomitant NSAID treatment were compared for cycles 1 and 2.

RESULTS

Data from 27 patients in each study were evaluable for the analysis of pemetrexed pharmacokinetics. Coadministration of aspirin did not alter pemetrexed pharmacokinetics; however, ibuprofen coadministration was associated with a 16% reduction in clearance, a 15% increase in maximum plasma concentration, and a 20% increase in area under the plasma concentration versus time curve but no significant change in V(ss) compared with pemetrexed alone. No febrile neutropenia occurred in any patient, and no increase in pemetrexed-related toxicity was associated with NSAID administration.

CONCLUSIONS

Pemetrexed (500 mg/m(2)) with vitamin supplementation is well tolerated and requires no dosage adjustment when coadministered with aspirin (in patients with CrCl > or =60 mL/min) or ibuprofen (in patients with CrCl > or =80 mL/min).

Lumiracoxib Does Not Affect Methotrexate Pharmacokinetics in Rheumatoid Arthritis Patients

BACKGROUND

Methotrexate and nonsteroidal antiinflammatory drugs are frequently coadministered in the treatment of rheumatoid arthritis (RA).

OBJECTIVE

To evaluate the effect of lumiracoxib, a novel cyclooxygenase-2 selective inhibitor, on methotrexate pharmacokinetics and short-term safety in patients with RA.

METHODS

This multicenter, randomized, double-blind, placebo-controlled crossover study enrolled 18 patients (mean age 49.1 y) with stable RA. Patients were randomized to receive methotrexate 7.5–15 mg orally once weekly plus either lumiracoxib 400 mg/day or placebo for 7 days. Patients then received the other treatment combination for an additional 7 days. Serial blood and urine were collected for 24 hours after the methotrexate dose on day 1 (methotrexate alone) and days 8 and 15 (combination treatment).

RESULTS

Plasma methotrexate pharmacokinetics (AUC0–t, maximum concentration [Cmax], time to Cmax) and methotrexate protein binding were similar for methotrexate alone (108.0 ng•h/mL, 26.7 ng/mL, 1.5 h, and 57.1%, respectively), methotrexate/lumiracoxib (110.2 ng•h/mL, 27.5 ng/mL, 1.0 h, and 53.7%, respectively), and methotrexate/placebo (101.8 ng•h/mL, 22.6 ng/mL, 1.0 h, and 57.0%, respectively). Similarly, no clinically significant difference was found in the urinary excretion of methotrexate. Mean exposure to the 7–OH metabolite was lower when methotrexate was given with lumiracoxib compared with placebo, shown by a reduction in AUC and Cmax, although similar amounts of the metabolite were recovered in urine following both lumiracoxib and placebo. Coadministration of methotrexate and lumiracoxib was well tolerated.

CONCLUSIONS

Lumiracoxib had no significant effect on the pharmacokinetics, protein binding, or urinary excretion of coadministered methotrexate in patients with RA.

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.

Combining the new biologic agents with our current psoriasis armamentarium

Combination therapy, rotational therapy, and sequential therapy have been used for psoriasis in attempts to achieve greater efficacy and greater safety. The purpose of this manuscript is to review potential advantages and disadvantages of new biologic agents as we look forward to their use in combination regimens with other systemic, topical, and light therapies. Data on the efficacy and toxicity of existing systemic therapies and new biologic agents is reviewed with an emphasis on potential additive or synergistic benefits or toxicities. The mechanism of action of biologic agents differs from systemic agents currently in use, suggesting that there may be additive effects in treating psoriasis. The absence of hepatotoxicity and nephrotoxicity are important advantages when considering combination therapy with biologic agents. The advantages of the use of biologic therapies in combination or rotation with other systemic agents will have to be demonstrated in clinical trials. Mechanisms of action of the biologic therapies suggest that there is potential for additive benefit when used in combination regimens.

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.

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.