Zomepirac Acyl Glucuronide Is Responsible for Zomepirac-Induced Acute Kidney Injury in Mice.

Glucuronidation, an important phase II metabolic route, is generally considered to be a detoxification pathway. However, acyl glucuronides (AGs) have been implicated in the toxicity of carboxylic acid drugs due to their electrophilic reactivity. Zomepirac (ZP) was withdrawn from the market because of adverse effects such as renal toxicity. Although ZP is mainly metabolized to acyl glucuronide (ZP-AG) by UDP-glucuronosyltransferase, the role of ZP-AG in renal toxicity is unknown. In this study, we established a ZP-induced kidney injury mouse model by pretreatment with tri-o-tolyl phosphate (TOTP), a nonselective esterase inhibitor, and l-buthionine-(S,R)-sulfoximine (BSO), a glutathione synthesis inhibitor. The role of ZP-AG in renal toxicity was investigated using this model. The model showed significant increases in blood urea nitrogen (BUN) and creatinine (CRE), but not alanine aminotransferase. The ZP-AG concentrations were elevated by cotreatment with TOTP in the plasma and liver and especially in the kidney. The ZP-AG concentrations in the kidney correlated with values for BUN and CRE. Upon histopathological examination, vacuoles and infiltration of mononuclear cells were observed in the model mouse. In addition to immune-related responses, oxidative stress markers, such as the glutathione/disulfide glutathione ratio and malondialdehyde levels, were different in the mouse model. The suppression of ZP-induced kidney injury by tempol, an antioxidant agent, suggested the involvement of oxidative stress in ZP-induced kidney injury. This is the first study to demonstrate that AG accumulation in the kidney by TOTP and BSO treatment could explain renal toxicity and to show the in vivo toxicological potential of AGs.

Validation and clinical application of an LC-ESI-MS/MS method for simultaneous determination of tolmetin and MED5, the metabolites of amtolmetin guacil in human plasma.

A highly sensitive, rapid assay method has been developed and validated for the simultaneous estimation of tolmetin (TMT) and MED5 in human plasma with liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the positive-ion mode. A simple solid-phase extraction process was used to extract TMT and MED5 along with mycophenolic acid (internal standard, IS) from human plasma. Chromatographic separation was achieved with 0.2% formic acid-acetonitrile (25:75, v/v) at a flow rate of 0.50 mL/min on an X-Terra RP(18) column with a total run time of 2.5 min. The MS/MS ion transitions monitored were 258.1 → 119.0 for TMT, 315.1 → 119.0 for MED5 and 321.2 → 207.0 for IS. Method validation and clinical sample analysis were performed as per FDA guidelines and the results met the acceptance criteria. The lower limit of quantitation achieved was 20 ng/mL and the linearity was observed from 20 to 2000 ng/mL, for both the anlaytes. The intra-day and inter-day precisions were in the range 3.27-4.50 and 5.32-8.18%, respectively for TMT and 4.27-5.68 and 5.32-8.85%, respectively for MED5. This novel method has been applied to a clinical pharmacokinetic study.

Disposition and irreversible plasma protein binding of tolmetin in humans.

The pharmacokinetics and irreversible plasma protein binding of tolmetin were studied in six healthy subjects after the administration of a single, 400 mg dose of tolmetin. With HPLC analysis, tolmetin, tolmetin glucuronide, and the isomers of tolmetin glucuronide, which result from intramolecular acyl migration in vivo, were detected in the plasma up to 4 hours after administration, whereas these conjugates were present in the urine up to 24 hours. Irreversible binding of tolmetin to plasma proteins occurred in all subjects. Irreversible binding exhibited a better correlation with exposure to tolmetin glucuronide (r = 0.5618) and the isomers of tolmetin glucuronide (r = 0.8200) than with exposure to tolmetin (-0.3635). This is consistent with the hypothesis that covalent binding occurs via the acyl glucuronide.

Absorption and excretion of tolemetin in man.

Tolmetin, a nonsteroidal anti-inflammatory drug, is rapidly absorbed (10 to 20 min) and rapidly excreted (T1/2 congruent to 60 min) and shows a linear dose-plasma level response in the therapeutic dose range. Tolmetin does not affect its own metabolism on chronic administration. Tolmetin is displaced, in vitro, from plasma proteins by salicylic acid. This effect is reflected in minor changes in plasma levels and pharmacokinetic parameters when aspirin and tolmetin are coadministered.

Absorption and excretion of tolmetin in arthritic patients.

The absorption, kinetics, biotransformation, and excretion of tolmetin and its metabolites were studied in patients with rheumatoid arthritis (RA) to evaluate the effects of the disease on tolmetin disposition. Five RA patients were stabilized on tolmetin sodium (300 mg, 4 times daily for 14 days) before receiving a single oral solution dose of tolmetin-14C sodium (300 mg as the acid) on day 15. Tolmetin was rapidly and completely absorbed (peak time, 20 to 60 min) and eliminated rapidly from plasma with a biphasic decay curve (t1/2beta congruent to 2.1 hr). MCPA, the oxidative metabolite, appeared more slowly (peak time, 40 to 90 min) but was eliminated rapidly in a biphasic manner (t1/2beta congruent to 1.7 hr). The terminal elimination phases for both tolmetin and MCPA demonstrated a curvature which suggested possible nonlinearity in the kinetic disposition of the drug. There were no apparent effects of the disease on the kinetics of tolmetin or MCPA. Tolmetin, MCPA, and tolmetin glucuronide were recovered quantitatively in urine (0 to 72 hr) with most of the exretion occurring in the 0- to 24-hr period. A significant increase, relative to data on normal subjects, in the renal clearance of both tolmetin and MCPA was noted. Concomitant increase in the apparent volume of distribution secondary to reported decreases in the plasma protein binding of tolmetin appeared to be the reason for increased renal clearance of tolmetin.

Effect of probenecid on the formation and elimination of acyl glucuronides: studies with zomepirac.

When 100 mg oral zomepirac was taken with 500 mg b.i.d. oral probenecid by six healthy subjects, the disposition of zomepirac was markedly altered. Probenecid decreased total plasma clearance of zomepirac by 64%, which resulted in an increase in bioavailability from 0.55 without probenecid to 0.84 when given concurrently. The apparent metabolic clearance of zomepirac to form zomepirac acyl glucuronide was reduced 71% and zomepirac renal clearance, a minor elimination route, was reduced by 79%. When assayed by a method that prevents degradation of the labile acyl glucuronide, zomepirac glucuronide concentrations in plasma were comparable to those of zomepirac. Probenecid decreased the renal clearance of zomepirac glucuronide by 72%, which, together with the increased zomepirac levels, resulted in a 2.8-fold increase in the AUC of the conjugate. Urinary excretion of zomepirac glucuronide was reduced from 72% to 58% of the dose, but the excretion of free zomepirac was unchanged at 5% of the dose. The ratio of the total clearance/bioavailability of zomepirac in control subjects was 682 +/- 246 ml/min, which is double the value reported in previous studies of zomepirac disposition. We believe that this difference is due to degradation of the unstable zomepirac acyl glucuronide in the previous analytic methodologies used. Qualitatively, the effects of probenecid on zomepirac disposition are similar to those previously reported for other drugs of this class that are metabolized to acyl glucuronides. However, zomepirac appears unusual in that significant levels of its acyl glucuronide metabolite are found in vivo.

Passive versus electrotransport-facilitated transdermal absorption of ketorolac.

OBJECTIVE: To investigate the bioavailability (extent and rate of absorption) of ketorolac from two cutaneous absorption sources, active electrotransport and passive transdermal, and to examine the enantiomeric selectivity of bioavailability for each source. METHODS: Based on a crossover study in 12 healthy volunteers, the extent and rate of absorption of ketorolac, delivered by a patch, were found by estimating the input rate function of the drug. For that purpose, deconvolution was used in two steps. First, intravenous data were analyzed to estimate the ketorolac disposition function, and second, postpatch data were deconvolved to estimate the unknown patch input profile given the disposition function estimated in the first step. Because the input rate function curves to be estimated for the patches may be of arbitrary shape, a spline was used to model the patch input function, whereas intravenous data were modeled with use of a sum of exponentials. Differences in the extent of absorption (F) for the four treatment-enantiomer combinations were further examined with a mixed-effect regression model, based on the sets of four individual estimates of bioavailability. RESULTS: On average, the F value for the active electrotransport treatment, which exhibited the faster absorption rate, was four times greater than the F for the passive transdermal treatment. Further, during the passive treatment, R-ketorolac yielded an average F that is 42% greater than that for S-ketorolac and also exhibited a smaller absorption lag-time. During the active treatment, there was no important enantiomeric difference in either extent or rate of absorption.

Population pharmacodynamic model for ketorolac analgesia.

OBJECTIVE: To derive a population pharmacokinetic-pharmacodynamic model that characterizes the distribution of pain relief scores and remedication times observed in patients receiving intramuscular ketorolac for the treatment of moderate to severe postoperative pain. BACKGROUND: The data analysis approach deals with the complexities of analyzing analgesic trial data: (1) repeated measurements, (2) ordered categorical response variables, and (3) nonrandom censoring because the patients can take a rescue medication if their pain relief is insufficient. METHODS: Patients (n = 522) received a single oral or intramuscular administration of placebo or a single intramuscular dose of 10, 30, 60, or 90 mg ketorolac for postoperative pain relief. Pain relief was measured periodically with use of a five-category ordinal scale up to 6 hours after dosing. In this period, 288 patients received additional medication because of insufficient pain relief. Pharmacokinetic data was available for 85 subjects. Models were fitted to the data with the NONMEM program. RESULTS: The pharmacokinetic data was best described by a two-compartment model with first-order absorption. Pain relief was found to be a function of drug concentration (Emax model), time (waxing and waning of placebo effect), and an individual random effect. The drug concentration at half-maximal effect (EC50) and the first-order rate constant (keo) half-life for pain relief were 0.37 mg/L and 24 minutes. The probability of remedication was found to be a function of the observed level of pain relief and was found to increase with time. Monte Carlo simulations showed that adequate pain relief was achieved in 50% of the patients at 41, 27, 23, and 21 minutes after 10, 30, 60, or 90 mg of intramuscular ketorolac. Adequate pain relief was maintained up to 6 hours in 50%, 70%, 78%, and 81% of patients after these four doses. Only 25% of the patients achieved adequate pain relief with placebo. CONCLUSIONS: A population pharmacokinetic-pharmacodynamic model for the analgesic efficacy of intramuscular ketorolac was derived. The simulated relationship between dose, time, and percentage of patients with adequate pain relief suggested that 30 mg intramuscular ketorolac was the optimal initial dose for postoperative pain relief.

Zomepirac kinetics in healthy males.

Kinetics of zomepirac, an oral, nonnarcotic analgesic, were studied in healthy males in 3 clinical experiments. In study A, zomepirac 100 mg was taken as tablet, capsule, and solution. Bioavailability of zomepirac from the 3 dosage forms was much the same. Zomepirac absorption was rapid, peak plasma concentrations being reached within 1 to 1 hr. Plasma concentration profile could be described by the 2-compartmentoral absorption model with an absorption rate constant (Ka) of 7.66 hr-1 t 1/2 = 0.09 hr), a rapid disposition rate constant (alpha) of 0.75 hr-1 (t 1/2 = 0.94 hr), and a slow disposition rate constant (beta) of 0.16 hr-1 (t 1/2 = 4.3 hr). In study B, safety and acceptability were established with 100 mg 4 times a day for 14 days followed by 150 mg 4 times a day for 14 days. Zomepirac plasma levels indicated attainment of steady state within less than 3 days of treatment. There was little drug accumulation on the regimens studied. There was no change in plasma kinetics after 14 days on either regimen. In study C, dose/bioavailability response was followed at 50-, 100-, and 200-mg dose levels. There were linear correlations between dose and peak plasma concentration, area under the plasma concentration-time curve, and urinary excretion of intact and total (intact + glucuronide conjugate) zomepirac during the 12 hr following drug administration.

Enantiomer-selective pharmacokinetics and metabolism of ketorolac in children.

OBJECTIVE: To compare the pharmacokinetics and metabolism of R(+)- and S(-)- ketorolac in children. METHODS: Children from 3 to 18 years old received 0.6 mg/kg racemic ketorolac intravenously. Serial blood samples were obtained for 12 hours, and urine was collected for 12 to 24 hours. Racemic ketorolac was measured in plasma, and racemic ketorolac, para-hydroxyketorolac, and ketorolac glucuronide were measured in urine by HPLC. S(-)- and R(+)-ketorolac were measured in plasma; S(-)- and R(+)-ketorolac and ketorolac glucuronide were measured in urine by chiral HPLC separation. Plasma pharmacokinetic parameters for racemic drug and both enantiomers were determined for each patient. RESULTS: Clearance of racemic ketorolac in children was approximately 2 times the clearance reported in adults. Clearance of the S(-) enantiomer was 4 times that of the R(+) enantiomer. Terminal half-life of S(-)-ketorolac was 40% that of the R(+) enantiomer, and the apparent volume of distribution of the S(-) enantiomer was greater than that of the R(+) form. Recovery of S(-)-ketorolac glucuronide was 2.3 times that of the R(+) enantiomer. CONCLUSION: The higher clearance in children suggests that the weight-adjusted dose of ketorolac may have to be greater for children to achieve plasma concentrations comparable to those of adults. Because of the greater clearance and shorter half-life of S(-)-ketorolac, pharmacokinetic predictions based on racemic assays may overestimate the duration of pharmacologic effect. Enantiomeric pharmacokinetic differences are best explained by stereoselective plasma protein binding. Selective glucuronidation of the S(-) enantiomer suggests that stereoselective metabolism may also be a contributing factor.

Protein binding of tolmetin.

The protein binding of the new nonsteroidal anti-inflammatory agent tolmetin to human serum albumin (HSA) and to the plasma of 8 healthy subjects was studied by equilibrium dialysis at 37 degrees and pH 7.4 with 14C-tolmetin. Over the total concentration (Ct) range 3.0 to 28.7 microgram/ml (therapeutic range), the fraction of tolmetin unbound to 4% HSA was largely invariant at 0.3%. At 100 microgram/ml the unbound fraction rose to 0.8 and at 434 microgram/ml to 3.6%. Within the therapeutic concentration range, tolmetin binding to 0.4% HSA was reduced in accordance with the law of mass action and at Ct = 26.2 microgram/ml, 10.5% was free. Analysis of the 0.4% HSA data showed tolmetin had 3 classes of binding sites (n1 = 1, K1 = 8.3 X 10(5) M-1; n2 = 4, K2 = 2.4 X 10(4) M-1; n3 = 44, K1 = 7.9 X 10(1) M-1). By studying the binding to 0.4% HSA at 23 degrees, it was established that the free energy change in binding for the first two classes of sites was entirely entropic in nature. Albumin accounted for almost all the binding of tolmetin in human plasma. The effect of other drugs, the tolmetin metabolite McN 2987 (5-p-carboxybenzoyl-1-methylpyrrole-2-acetic acid), tryptophan, and oleic acid on tolmetin binding to 4% HSA was studied using ultrafiltration and 14C-tolmetin. Aspirin and salicyclic acid decreased tolmetin binding and a combination of aspirin and salicyclic acid exerted a synergistic displacing effect. Indomethacin and ibuprofen had no effect while phenylhbutazone and acetaminophen increased tolmetin binding slightly. Tolmetin binding was decreased slightly by McN 2987 and tryptophan and markedly increased by oleic acid. McN 2987 was not bound as extensively as tolmetin. Binding of 14C-tolmetin to the plasma of 4 arthritic patients was studied by ultrafiltration and found to be less than to normal plasma and 4% HSA. Distribution of tolmetin in the whole blood of 8 healthy subjects using a centrifugation technique showed that the drug was not taken up by red blood cells at therapeutic concentrations.

Site of analgesic action of a non-steroidal, anti-inflammatory drug, tolmetin sodium, in rats.

1 The site of the analgesic action of tolmetin sodium was investigated by use of the acetic acid writhing test in rats. 2 Tolmetin sodium was administered to the rat between 15 and 60 min after intraperitoneal injection of 1 ml of a 1% acetic acid aqueous solution. Number of writhing was counted for 20 min beginning from 60 min after acetic acid injection. 3 When the rat was given tolmetin sodium 5 mg/kg orally, a relatively large quantity of tolmetin was found in the peritoneal exudate and there was a rough correlation between anti-writhing activity and the exudate tolmetin content. 4 Anti-writhing ED50 of tolmetin sodium was 1.42 (0.82-2.91) and 92.0 (57.0-140) microgram/kg when given intraperitoneally and intravenously, respectively, and the potency ratio of intraperitoneal to intravenous tolmetin sodium was 40.0 (18.5-80.2). This potency ratio for salicylic acid and morphine hydrochloride was 19.4 and 1.0, respectively. 5 When equipotent doses ( 5 microgram/kg i.p.; 200 microgram/kg i.v.) of tolmetin sodium were administered to the rat, the plasma tolmetin level after the intraperitoneal administration was less than one-fortieth that after the intravenous administration during the counting time of 20 min, while both the peritoneal exudate contents of tolmetin were nearly equal. 6 From these results, it is concluded that the site of anti-writhing action of tolmetin sodium is in the peritoneum and that tolmetin sodium produces its anti-writhing action mainly by a peripheral mechanism in the rat.

Disposition of zomepirac sodium in man.

Five healthy male human subjects were administered 200 mg oral solution doses of zomepirac-14C sodium. Plasma and urine samples were analyzed for zomepirac, hydroxyzomepirac, and zomepirac glucuronide. Zomepirac was the major circulating compound, with zomepirac glucuronide and hydroxyzomepirac accounting for the remainder of the radioactivity. Elimination half-lives for zomepirac, zomepirac glucuronide, and hydroxyzomepirac were 7.6, 8.2, and 7.8 hours, respectively. The dose was completely recovered in the urine (95 per cent in 72 hours). Zomepirac glucuronide constituted up to 90 per cent of the urinary radioactivity, with zomepirac and hydroxyzomepirac about 5 per cent each. The urinary zomepirac was probably present as a result of hydrolysis of zomepirac glucuronide. The plasma clearance of zomepirac was 189 +/- 23 ml/min. The metabolites were cleared by the kidney at rates of 343 +/- 88 ml/min (zomepirac glucuronide) and 339 +/- 88 ml/min (hydroxyzomepirac). Thus, metabolic clearance appears to be the sole mode of zomepirac elimination. The metabolites are then rapidly cleared by the kidneys.

Comparison of tolmetin kinetics in rheumatoid arthritis and matched healthy controls.

We could find no significant differences in the kinetics of tolmetin when comparing five rheumatoid arthritis patients with moderate disease activity with a carefully matched group of normal healthy volunteers. Further, there were no discernible clinically significant differences in the kinetics of tolmetin when comparing a single dose to one week of therapy. These results, although limited by the small number of subjects involved and the large interpatient variability, suggest that it may be possible to extrapolate pharmacokinetic data from normals to patients with moderately active disease.

Zomepirac--aspirin interactions in man.

The pharmacokinetic interaction between zomepirac and aspirin was studied in 12 healthy males who received a single dose of 100 mg zomepirac sodium on days 1 and 5 and 975 mg aspirin every 6 hours on days 2 to 5. The results indicated that in the presence of salicylate, the peak concentration of zomepirac was depressed; peak time, AUC(0-24 hr), and clearance of total drug remained unchanged. Percentage unbound zomepirac was increased twofold. In the presence of zomepirac, the peak concentration and AUC of salicylate were increased and clearance decreased. The data suggest that zomepirac and salicylate compete with each other for the enzymes and/or cofactors involved in glucuronidation. This competition for metabolic clearance offsets the consequences of the zomepirac-salicylate interactions at the plasma protein binding sites. However, in light of increased unbound zomepirac as well as decreased clearance of unbound drug, concomitant therapy of zomepirac and aspirin is not advised.

Review of the pharmacokinetics and metabolism of zomepirac in man and animals.

Zomepirac has been shown to be rapidly and completely absorbed after oral administration to man. Urinary excretion is the principal route for removal of zomepirac and its metabolites in man and in animals. Zomepirac is highly bound to plasma protein. The pharmacokinetics of zomepirac after single and multiple doses in man can be adequately described by a two-compartment oral absorption model. There is a linear relationship between dose and peak plasma concentration, AUC, and urinary excretion of zomepirac. The bioavailability of zomepirac was unaffected by single or repeated doses of antacid. The rhesus monkey has been shown to be a good predictive animal model for zomepirac's metabolism and pharmacokinetics in man, with glucuronidation found to be the principal route of metabolism in both species.

Effects of zomepirac on hemostasis in healthy adults and on platelet function in vitro.

Zomepirac, a new nonnarcotic analgesic, was studied in 25 healthy adults for possible effects on hemostasis. Given in a single 200-mg dose or for 15 days at 300 mg/day, zomepirac prolonged template bleeding time and caused transient decreases in platelet adhesiveness, in stimulated platelet aggregation, and in the release of platelet serotonin. The short duration of these effects contrasts with the known week-long duration of the effects of aspirin. Data from in vitro platelet function studies, correlated with plasma level determinations, indicate that these effects on platelet function in man are probably dependent only on the presence of intact zomepirac and not on any metabolites. The qualitative effects of zomepirac on platelets are assumed to be the consequence of reversible inhibition of prostaglandin synthetase in these cells. Platelet concentration and the humoral clotting mechanism were not affected by zomepirac. Although no unusual bleeding has been noted in patients given zomepirc postoperatively, it should be used with the same caution as aspirin in patients with known defects in platelet function or coagulation.

Ketorolac tromethamine pharmacokinetics and metabolism after intravenous, intramuscular, and oral administration in humans and animals.

In humans, ketorolac is completely bioavailable and its kinetics are linear. It is absorbed rapidly (half-life for absorption 3.8 min) after oral (fasting) and intramuscular administration; food delays but does not reduce its absorption. The drug is highly protein bound in humans (greater than 99%). The mean plasma elimination half-life is 5-6 hours, and ketorolac is not extensively distributed outside the vascular compartment (Vd beta 15 L). Virtually all of the drug-related material circulating in plasma is in the form of ketorolac (greater than 96%), with the only metabolite the pharmacologically inactive p-hydroxyketorolac (PHK). Humans excrete about 90% of the administered dose in urine. About 60% of drug-related material recovered from urine is ketorolac, about 12% is PHK, and 28% represents polar, glucuronide conjugates of ketorolac. The animal models in which ketorolac's metabolism and kinetics are most similar to those in humans are the mouse and monkey, respectively.

Bile duct ligation promotes covalent drug-protein adduct formation in plasma but not in liver of rats given zomepirac.

Acyl glucuronides are reactive electrophilic metabolites of carboxylate drugs, capable of undergoing hydrolysis, rearrangement and covalent binding reactions with proteins in vivo. Such covalent drug-protein adducts may be prerequisites for certain idiosyncratic immune and toxic responses in susceptible individuals. The present study examined the effect of experimental cholestasis on the extent and pattern of formation of protein adducts in plasma and liver of rats given the non-steroidal antiinflammatory drug (NSAID) zomepirac (ZP). Groups of intact, bile-exteriorized and bile duct-ligated rats given a 50 mg/kg i.v. dose of ZP were studied for 24 hr. In intact rats, only 1.4% of the dose was recovered as the sum of ZP, ZP acyl glucuronide (ZAG) and its rearrangement isomers (iso-ZAG) in urine in 24 hr. In bile-exteriorized animals, 0.5% of the dose was recovered in urine in 24 hr, with 31.6% of the dose being recovered in bile (2.7% as ZP, 20.0% as ZAG and 8.9% as iso-ZAG). In the bile duct-ligated group, recovery of dose in 24 hr urine totalled 17.5% (1.7% as ZP, 6.7% as ZAG and 9.1% as iso-ZAG). ZAG and iso-ZAG were measurable in plasma only in the bile duct-ligated group, and covalent binding of ZP to plasma proteins was much higher (5-6 fold) than in intact or bile-exteriorized rats. Total adduct concentrations in liver were not significantly different among the three groups. Immunoblotting using a polyclonal ZP antiserum confirmed that serum albumin was a major target protein in plasma. The major ZP-modified bands in the livers of intact and bile-exteriorized rats were at about 110, 140 and 200 kDa. However, the bands at 110 and 140 kDa were much lower in the livers of bile duct-ligated rats. The results show that about 30% of ZP doses are normally excreted as ZAG and its isomers in bile, with only minor excretion in urine. Bile duct ligation shunts the glucuronide into blood (and urine), strongly promoting adduct formation with plasma proteins, and alters the pattern but not the total quantity of drug-modified proteins formed in the liver.

Determination of tolmetin in human plasma by GLC and spectrophotometric procedures.

GLC and spectrophotometric methods for the determination of tolmetin in plasma were developed. The methods can detect tolmetin in concentrations above 0.5 mug/ml. The plasma levels obtained with a 600-mg dose of tolmetin to a human subject are reported.