Influence of meloxicam on furosemide pharmacokinetics and pharmacodynamics in healthy volunteers

Voriconazole increases while itraconazole decreases plasma meloxicam concentrations

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

Population pharmacokinetic analysis of meloxicam in rheumatoid arthritis patients

AIM

To perform a nonlinear mixed effect modelling (NONMEM) population pharmacokinetic analysis of meloxicam plasma concentrations in rheumatoid arthritis (RA) patients participating in three clinical trials, and to evaluate the effects of age, weight, gender and concomitant medications on meloxicam pharmacokinetics.

METHODS

Meloxicam was administered to RA patients once daily for 3 weeks or 6 months at doses between 7.5 and 60 mg. Plasma samples were obtained at least 7 days after the first dose and meloxicam plasma concentrations were quantified by h.p.l.c.

RESULTS

NONMEM analysis was conducted on plasma samples derived from 586 patients. A one-compartmental model was found to describe the data adequately. For a typical subject in the population, a clearance of 0.377 l h-1 (95% confidence interval (CI) 0.0304-0.449) in males and 0.347 l h-1 (95% CI 0.274-0.419) in females was obtained. The volume of distribution was estimated to be 14.9 l. The findings were corroborated by subsequent analysis using WinBUGS. Analysis of covariates showed that age and gender both significantly (P < 0.005) affected clearance. The effect of age was relatively small and a dose adjustment of <10% was deemed unnecessary. Differences between males and females were attributed to differences in weight. No clinically relevant drug-drug interactions were found, although sulphasalazine and glucocorticoids both significantly (P < 0.005) affected meloxicam clearance (+19% and - 12%, respectively). The mechanisms by which these agents affect meloxicam clearance remain to be elucidated.

CONCLUSIONS

The population pharmacokinetic meloxicam data from patients with RA gave similar results to those obtained from phase I trials. However, uncommon drug interactions may not be detected in phase I trials because of the small number of observations made.

Meloxicam

Meloxicam (Mobic trade mark, Boehringer Ingelheim) is a relatively new oral non-steroidal anti-inflammatory drug (NSAID) approved for the treatment of osteoarthritis in the US. It has also been evaluated for the treatment of rheumatoid arthritis, ankylosing spondylitis and acute 'rheumatic' pain. Meloxicam has been shown to be COX-2 preferential, particularly at its lowest therapeutic dose, and is anti-inflammatory by inhibiting prostanoid synthesis in inflammatory cells. Since it is COX-2 preferential, it would be expected to have less gastrointestinal toxicity than non-selective NSAIDs. In clinical trials of meloxicam in osteoarthritis, it was found to be as effective as piroxicam, diclofenac and naproxen with less clinical gastrointestinal symptoms and less perforations, obstructions and bleeds by meta-analysis. Adverse events, including peripheral oedema and hypertension, occurred at a similar rate as with traditional NSAIDs.

Meloxicam

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The cyclooxygenase-2 inhibitors: safety and effectiveness

OBJECTIVE

To review the development of cyclooxygenase-2 (COX-2) inhibitors and discuss specific agents that are currently under investigation or have been marketed.

DATA SOURCES

Primary literature on selective COX inhibitors was identified from a comprehensive MEDLINE, English-literature search from January 1966 through September 1998, with additional studies selected by review of the references. Abstracts from recent meetings and package insert literature from approved agents were also used as source material. Indexing terms included COX-2 inhibitors, meloxicam, celecoxib, rofecoxib, flosulide, SC-58635, and MK-966.

STUDY SELECTION

Human clinical, pharmacokinetic, and dose-ranging trials performed in Europe and the US and randomized comparative trials were reviewed.

DATA SYNTHESIS

With the discovery of at least two COX isoforms, a better understanding of the mechanism of action and gastrointestinal toxicity of nonsteroidal antiinflammatory drugs (NSAIDs) has been realized. While COX-1 is involved in physiologic maintenance, COX-2 seems to be involved in inflammation, mitogenesis, and specialized signal transductions. Selective COX-2 inhibitors may allow maximum antiinflammatory activity while improving the safety profile associated with NSAID therapy. Celecoxib and rofecoxib have been approved by the Food and Drug Administration for the treatment of osteo- and rheumatoid arthritis; meloxicam is undergoing Phase III clinical trials. Preliminary data indicate that the selective COX-2 inhibitors provide analgesic and antiinflammatory efficacy comparable with older NSAIDs, with fewer adverse gastrointestinal effects.

CONCLUSIONS

Specific COX-2 inhibitors offer promising benefits over older NSAIDs with regard to gastrointestinal safety while maintaining analgesic and antiinflammatory efficacy. Further study is required to determine long-term efficacy and safety in clinical use.

Meloxicam pharmacokinetics in renal impairment

AIMS

The aim of the present study was to determine how the pharmacokinetics of meloxicam are affected by kidney dysfunction and consequently to define the appropriate dose for the use of meloxicam in patients with mild or moderate renal impairment.

METHODS

Meloxicam was administered to subjects with mild (creatinine clearance 41-60 ml min-1) to moderate (20-40 ml min-1) renal impairment compared with normal renal function (> 60 ml min-1). Thirty-eight subjects received meloxicam 15 mg once daily over 9 days. Meloxicam plasma concentrations were determined from blood samples taken during the study and pharmacokinetic parameters calculated according to noncompartmental methods.

RESULTS

Subjects with no or mild renal impairment showed similar pharmacokinetic profiles (geometric mean AUCSS (%gCV) 55 (33%) vs 55 (38%) micrograms ml-1 h). Subjects with moderate renal impairment demonstrated lower total plasma meloxicam concentrations (AUCSS 35 (50%) micrograms ml-1 h, with corresponding higher plasma clearance (P = 0.013) compared with subjects with no renal impairment. However, this was combined with higher meloxicam free fractions in moderately impaired subjects such that free meloxicam concentrations were similar in all three groups. Meloxicam was well tolerated with few adverse events occurring and no difference in incidence observable between groups.

CONCLUSIONS

On the basis of these results there is no necessity for a dosage adjustment when administering meloxicam to patients with mild to moderate renal impairment.

Meloxicam

Meloxicam is a new nonsteroidal anti-inflammatory drug (NSAID) developed for the treatment of rheumatoid arthritis and osteoarthritis. It has greater in vitro and in vivo inhibitory action against the inducible isoform of cyclo-oxygenase (COX-2), which is implicated in the inflammatory response, than against the constitutive form of this enzyme (COX-1), inhibition of which is associated with gastric, renal and other adverse effects. It has anti-inflammatory effects similar to or better than those of other NSAIDs in animal models, and a greater therapeutic ratio (ulcerogenic potential:efficacy in adjuvant arthritis). In healthy volunteers meloxicam 7.5 or 15 mg caused less gastrointestinal mucosal damage on endoscopy than piroxicam 20 mg, with a significant difference between meloxicam 7.5 mg and piroxicam. In comparative clinical trials, meloxicam was at least as effective as piroxicam and naproxen in patients with rheumatoid arthritis, and diclofenac and piroxicam in patients with osteoarthritis. Meloxicam was at least as well tolerated as piroxicam, diclofenac or naproxen overall but had improved gastrointestinal tolerability compared with these agents.