Mechanism of Action
Meloxicam is a nonsteroidal anti-inflammatory drug (NSAID) that exhibits antiinflammatory,
analgesic, and antipyretic activities in animal models. The mechanism of action
of meloxicam, like that of other NSAIDs, may be related to prostaglandin synthetase
(cyclo-oxygenase) inhibition.
Pharmacokinetics
Absorption
The absolute bioavailability of meloxicam capsules was 89% following a single
oral dose of 30 mg compared with 30 mg IV bolus injection. Following single
intravenous doses, dose-proportional pharmacokinetics were shown in the range
of 5 mg to 60 mg. After multiple oral doses the pharmacokinetics of meloxicam
capsules were dose-proportional over the range of 7.5 mg to 15 mg. Mean Cmax
was achieved within four to five hours after a 7.5 mg meloxicam tablet was taken
under fasted conditions, indicating a prolonged drug absorption. With multiple
dosing, steady state concentrations were reached by Day 5. A second meloxicam
concentration peak occurs around 12 to 14 hours post-dose suggesting biliary
recycling.
Meloxicam oral suspension doses of 7.5 mg/5 mL and 15 mg/10 mL have been found
to be bioequivalent to meloxicam 7.5 mg and 15 mg capsules, respectively. Meloxicam
capsules have been shown to be bioequivalent to Mobic® (meloxicam) tablets.
Table 1: Single Dose and Steady State Pharmacokinetic Parameters
for Oral 7.5 mg and 15 mg Meloxicam (Mean and % CV)1
Pharmacokinetic
Parameters
(%CV) |
Steady State |
Single Dose |
Healthy
male adults
(Fed)2 |
Elderly
males
(Fed)2 |
Elderly
females
(Fed)2 |
Renal
failure
(Fasted) |
Hepatic
insufficiency
(Fasted) |
| 7.5 mg³ tablets |
15 mg capsules |
15mg capsules |
15mg capsules |
15 mg capsules |
| N |
18 |
5 |
8 |
12 |
12 |
| Cmax[μg/mL] |
1.05 (20) |
2.3 (59) |
3.2(24) |
0.59(36) |
0.84 (29) |
| tmax[h] |
4.9 (8) |
5 (12) |
6(27) |
4(65) |
10 (87) |
| t½[h] |
20.1 (29) |
21 (34) |
24(34) |
18(46) |
16 (29) |
| CL/f[mL/min] |
8.8 (29) |
9.9 (76) |
5.1(22) |
19(43) |
11 (44) |
| Vz/f4[L] |
14.7 (32) |
15 (42) |
10(30) |
26(44) |
14 (29) |
1The parameter values in the
Table are from various studies
2not under high fat conditions
3MOBIC tablets
4 Vz/f =Dose/(AUC•Kel) |
Food and Antacid Effects
Administration of meloxicam capsules following a high fat breakfast (75 g of
fat) resulted in mean peak drug levels (i.e., Cmax) being increased by approximately
22% while the extent of absorption (AUC) was unchanged. The time to maximum
concentration (Tmax) was achieved between 5 and 6 hours. In comparison, neither
the AUC nor the Cmax values for meloxicam suspension were affected following
a similar high fat meal, while mean Tmax values were increased to approximately
7 hours. No pharmacokinetic interaction was detected with concomitant administration
of antacids. Based on these results, MOBIC tablets/oral suspension can be administered
without regard to timing of meals or concomitant administration of antacids.
Distribution
The mean volume of distribution (Vss) of meloxicam is approximately 10 L. Meloxicam
is ~ 99.4% bound to human plasma proteins (primarily albumin) within the therapeutic
dose range. The fraction of protein binding is independent of drug concentration,
over the clinically relevant concentration range, but decreases to ~ 99% in
patients with renal disease. Meloxicam penetration into human red blood cells,
after oral dosing, is less than 10%. Following a radiolabeled dose, over 90%
of the radioactivity detected in the plasma was present as unchanged meloxicam.
Meloxicam concentrations in synovial fluid, after a single oral dose, range
from 40% to 50% of those in plasma. The free fraction in synovial fluid is 2.5
times higher than in plasma, due to the lower albumin content in synovial fluid
as compared to plasma. The significance of this penetration is unknown.
Metabolism
Meloxicam is almost completely metabolized to four pharmacologically inactive
metabolites. The major metabolite, 5'-carboxy meloxicam (60% of dose), from
P-450 mediated metabolism was formed by oxidation of an intermediate metabolite
5'-hydroxymethyl meloxicam which is also excreted to a lesser extent (9% of
dose). In vitro studies indicate that cytochrome P-450 2C9 plays an important
role in this metabolic pathway with a minor contribution of the CYP 3A4 isozyme.
peroxidase activity is probably responsible for the other two metabolites which
account for 16% and 4% of the administered dose, respectively.
Excretion
Meloxicam excretion is predominantly in the form of metabolites, and occurs
to equal extents in the urine and feces. Only traces of the unchanged parent
compound are excreted in the urine (0.2%) and feces (1.6%). The extent of the
urinary excretion was confirmed for unlabeled multiple 7.5 mg doses: 0.5%, 6%
and 13% of the dose were found in urine in the form of meloxicam, and
the 5'-hydroxymethyl and 5'-carboxy metabolites, respectively. There is significant
biliary and/or enteral secretion of the drug. This was demonstrated when oral
administration of cholestyramine following a single IV dose of meloxicam decreased
the AUC of meloxicam by 50%.
The mean elimination half-life (t½) ranges from 15 hours to 20 hours. The
elimination half-life is constant across dose levels indicating linear metabolism
within the therapeutic dose range. Plasma clearance ranges from 7 to 9 mL/min.
Special Populations
Pediatric
After single (0.25 mg/kg) dose administration and after achieving steady-state
(0.375 mg/kg/day), there was a general trend of approximately 30% lower exposure
in younger patients (2-6 years old) as compared to the older patients (7-16
years old). The older patients had meloxicam exposures similar (single dose)
or slightly reduced (steadystate) to those in the adult patients, when using
AUC values normalized to a dose of 0.25 mg/kg (see DOSAGE AND ADMINISTRATION).
The meloxicam mean (SD) elimination half-life was 15.2 (10.1) and 13.0 hours
(3.0) for the 2-6 year old patients, and 7-16 year old patients, respectively.
In a covariate analysis, utilizing population pharmacokinetics body-weight,
but not age, was the single predictive covariate for differences in the meloxicam
apparent oral plasma clearance. The body-weight normalized apparent oral clearance
values were adequate predictors of meloxicam exposure in pediatric patients.
The pharmacokinetics of Mobic® (meloxicam) tablets/oral suspension in pediatric
patients under 2 years of age have not been investigated.
Geriatric
Elderly males ( ≥ 65 years of age) exhibited meloxicam plasma concentrations
and steady state pharmacokinetics similar to young males. Elderly females ( ≥ 65
years of age) had a 47% higher AUCss and 32% higher Cmax,ss as compared to younger
females ( ≤ 55 years of age) after body weight normalization. Despite the increased
total concentrations in the elderly females, the adverse event profile was comparable
for both elderly patient populations. A smaller free fraction was found in elderly
female patients in comparison to elderly male patients.
Gender
Young females exhibited slightly lower plasma concentrations relative to young
males. After single doses of 7.5 mg MOBIC, the mean elimination half-life was
19.5 hours for the female group as compared to 23.4 hours for the male group.
At steady state, the data were similar (17.9 hours vs. 21.4 hours). This pharmacokinetic
difference due to gender is likely to be of little clinical importance. There
was linearity of pharmacokinetics and no appreciable difference in the Cmax
or Tmax across genders.
Hepatic Insufficiency
Following a single 15 mg dose of meloxicam there was no marked difference in
plasma concentrations in subjects with mild (Child-Pugh Class I) and moderate
(Child-Pugh Class II) hepatic impairment compared to healthy volunteers. Protein
binding of meloxicam was not affected by hepatic insufficiency. No dose adjustment
is necessary in mild to moderate hepatic insufficiency. Patients with severe
hepatic impairment (Child-Pugh Class III) have not been adequately studied.
Renal Insufficiency
Meloxicam pharmacokinetics have been investigated in subjects with different
degrees of renal insufficiency. Total drug plasma concentrations decreased with
the degree of renal impairment while free AUC values were similar. Total clearance
of meloxicam increased in these patients probably due to the increase in free
fraction leading to an increased metabolic clearance. There is no need for dose
adjustment in patients with mild to moderate renal failure (CrCL > 15 mL/min).
Patients with severe renal insufficiency have not been adequately studied. The
use of MOBIC tablets/oral suspension in subjects with severe renal impairment
is not recommended (see WARNINGS, Advanced Renal Disease).
Hemodialysis
Following a single dose of meloxicam, the free Cmax plasma concentrations were
higher in patients with renal failure on chronic hemodialysis (1% free fraction)
in comparison to healthy volunteers (0.3% free fraction). Hemodialysis did not
lower the total drug concentration in plasma; therefore, additional doses are
not necessary after hemodialysis. Meloxicam is not dialyzable.
Clinical Trials
Osteoarthritis and Rheumatoid Arthritis
The use of MOBIC for the treatment of the signs and symptoms of osteoarthritis of the knee and hip was evaluated in a 12-week double-blind controlled trial.
MOBIC (3.75 mg, 7.5 mg and 15 mg daily) was compared to placebo. The four primary
endpoints were investigator's l assessment, patient pain assessment, andglobal
assessment, patient total WOMAC score (a self-administered questionnaire addressing
pain, function and stiffness). Patients on MOBIC 7.5 mg daily and MOBIC 15 mg
daily showed significant improvement in each of these endpoints compared with
placebo.
The use of MOBIC for the management of signs and symptoms of osteoarthritis
was evaluated in six double-blind, active-controlled trials outside the U.S.
ranging from 4 weeks to 6 months duration. In these trials, the efficacy of
MOBIC, in doses of 7.5 mg/day and 15 mg/day, was comparable to piroxicam 20
mg/day and diclofenac SR 100 mg/day and consistent with the efficacy seen in
the U.S. trial.
The use of MOBIC for the treatment of the signs and symptoms of rheumatoid arthritis was evaluated in a 12-week double-blind, controlled multinational trial. MOBIC (7.5 mg, 15 mg and 22.5 mg daily) was compared to placebo. The
primary endpoint in this study was the ACR20 response rate, a composite measure
of clinical, laboratory and functional measures of RA response. Patients receiving
MOBIC 7.5 mg and 15 mg daily showed significant improvement in the primary endpoint
compared with placebo. No incremental benefit was observed with the 22.5 mg
dose compared to the 15 mg dose.
Higher doses of MOBIC (22.5 mg and greater) have been associated with an increased
risk of serious GI events; therefore the daily dose of MOBIC should not exceed
15 mg.
Pauciarticular and Polyarticular Course Juvenile Rheumatoid Arthritis (JRA)
The use of MOBIC for the treatment of the signs and symptoms of pauciarticular
or polyarticular course Juvenile Rheumatoid Arthritis in patients 2 years of
age and older was evaluated in two 12-week, double-blind, parallel-arm, active-controlled
trials. Both studies included three arms: naproxen and two doses of meloxicam.
In both studies, meloxicam dosing began at 0.125 mg/kg/day (7.5 mg maximum)
or 0.25 mg/kg/day (15 mg maximum), and naproxen dosing began at 10 mg/kg/day.
One study used these doses throughout the 12-week dosing period, while the other
incorporated a titration after 4 weeks to doses of 0.25 mg/kg/day and 0.375
mg/kg/day (22.5 mg maximum) of meloxicam and 15 mg/kg/day of naproxen.
The efficacy analysis used the ACR Pediatric 30 responder definition, a composite
of parent and investigator assessments, counts of active joints and joints with
limited range of motion, and erythrocyte sedimentation rate. The proportion
of responders were similar in all three groups in both studies, and no difference
was observed between the meloxicam dose groups.
Last updated on RxList: 7/31/2008