Nimesulide binding to components within blood

Insights into the effect of glucose on the binding between human serum albumin and the nonsteroidal anti-inflammatory drug nimesulide

Glucose interacts with human serum albumin (HSA, the main protein responsible for the biodistribution of drugs in the bloodstream) and consequently affects the binding capacity of exogenous compounds. Thus, in this work, the interactive profile between HSA and the anti-inflammatory drug nimesulide (NMD, used mainly by patients with diabetic neuropathy to relieve acute or chronic pains) was characterized in nonglycemic, normoglycemic (80 mg/dL), and hyperglycemic (320 mg/dL) conditions by biophysics techniques. There is a spontaneous and ground-state association HSA:NMD under physiological conditions. Therefore, the Stern-Volmer constant (Ksv) can also be used to estimate the binding affinity. The Ksv values for nonglycemic, normoglycemic, and hyperglycemic conditions are around 104 M-1, indicating a moderate affinity of NMD to albumin that was slightly improved by glucose levels. Additionally, the binding is enthalpically and entropically driven mainly into subdomains IIA or IIIA. The binding perturbs weakly the α-helix content of albumin, however, glucose potentially stabilizes the tertiary structure, decreasing the structural perturbation upon NMD binding and improves the complex HSA:NMD stability. Overall, the biophysical characterization indicated that glucose levels might slightly positively impact the pharmacokinetic profile of NMD, allowing NMD to achieve its therapeutical potential without affecting drastically its effective dosages.

Incidence of potential drug interactions in medication prescriptions for children and adolescents in the University Hospital Olomouc, Czech Republic

Drug interactions are important potential causes of adverse drug reactions. However, studies of their occurrence in children are almost entirely lacking. This study evaluates the incidence of potential drug interactions (PDIs) in medication prescriptions for children. The study was performed at the University Hospital in Olomouc. PDIs in each patient's prescriptions were identified. Multivariate analysis was performed in order to assess the risk factors confounding the potential interactions. Univariate analysis was used to assess which diagnostic groups and medication groups significantly increase or lower the odds of a potential drug-drug interaction. A total of 6,078 patients meeting the inclusion criteria entered the study. They received 19,522 prescriptions. PDIs were identified in 3.83 % of patients (moderate-to-severe cases in 0.47 %). Patient age (p = 0.008), the average number of prescriptions per visit (p < 0.0001), and the number of visits per year (p < 0.0001) were found to increase the risk of drug interaction. The presence of epilepsy, leukemia, or rheumatoid arthritis and related disease diagnoses were discovered to increase the risk of PDIs significantly.

CONCLUSION

The risk of PDIs in children is low, but it increases significantly with age and the number of drugs prescribed, particularly antiepileptics and immunosuppressants. The finding of a potential interaction in 0.47 % of all children in whom any medication was prescribed should not be underestimated since it means a significant risk for one child out of every 200, and it is also substantially higher in the chronically ill. Pediatricians should be aware of relevant interactions and should prevent them by therapeutic drug monitoring or appropriate clinical and laboratory monitoring.

Oral and intravenous administration of nimesulide in the horse: rational dosage regimen from pharmacokinetic and pharmacodynamic data

REASONS FOR PERFORMING STUDY

The selective COX-2-inhibitor nimesulide is used extra-label in equine veterinary practice as an anti-inflammatory agent. However, there are no data on which to base the rational use of the drug in this species.

OBJECTIVES

To determine the effective COX selectivity of nimesulide in the horse, and suggest a suitable dosing schedule.

METHODS

The pharmacokinetics of nimesulide in the horse after oral administration (1 mg/kg bwt), and oral and i.v. administration (1.5 mg/kg bwt) were investigated, effects of feeding status on bioavailability determined, and plasma protein binding of the drug and its principal metabolites measured. Compartmental and noncompartmental pharmacokinetic analyses were performed. The plasma concentration-time profile was used, together with in vitro literature data on nimesulide inhibition of COX isoforms, to determine the effective COX selectivity of nimesulide in the horse, and suggest a suitable dosing schedule.

RESULTS AND CONCLUSIONS

The findings suggest that 1.5 mg/kg bwt may produce adequate clinical effects, and the dosing interval should be 12-24 h depending on condition severity. However, at that dose, the concentration in the animal exceeds the in vitro IC50 for both isoforms, so that COX-1/COX-2 selectivity is lost and side-effects due to COX-1 inhibition are a possibility. Nimesulide should therefore be used with caution in equine clinical practice.

Dual, but not selective, COX-1 and COX-2 inhibitors, attenuate acetic acid-evoked bladder irritation in the anaesthetised female cat

Non-selective cyclooxygenase (COX) inhibitors exert effects on lower urinary tract function in several species. The exact contributions of COX-1 and COX-2 isozymes have not been studied much. The present studies investigated the effects of non- and selective COX inhibitors on bladder irritation in the cat.Chloralose-anaesthetised female cats were catheterised through the bladder dome for cystometric evaluation of bladder responses to intravesical infusion of saline or acetic acid. Bladder capacity, voiding efficiency, threshold pressure, and reflex-evoked bladder contraction amplitude and duration were measured. The cat COX selectivity of the doses of inhibitors examined was determined using an in vitro whole-blood assay and analysis of plasma levels. Pretreatment with indomethacin or ketoprofen (non-selective COX inhibitors; 0.3 mg kg(-1) i.v.) inhibited acetic acid-evoked irritation (characterised by a decrease in bladder capacity in vehicle pretreated animals). FR-122047 (selective COX-1 inhibitor), NS-398 and nimesulide (selective COX-2 inhibitors; 1 and 3 mg kg(-1) i.v.) had no effects on bladder irritation. Analysis of plasma levels of the doses examined and determination of COX-1 and COX-2 inhibition in cat whole blood confirmed the reported selectivity of these compounds in this species. The present studies suggest that dual COX inhibition is required to attenuate acetic acid-evoked bladder irritation in the cat.

Mechanism of interaction of the non-steroidal antiinflammatory drugs meloxicam and nimesulide with serum albumin

The mechanism of interaction of the non-steroidal antiinflammatory drugs meloxicam and nimesulide with human and bovine serum albumin has been studied using fluorescence spectroscopy. There was only one high affinity site on serum albumin for both the drugs with association constants of the order of 10(5). Negative enthalpy (DeltaH(0)) and positive entropy (DeltaS(0)) values in the case of both meloxicam and nimesulide showed that both hydrogen bonding and hydrophobic interactions play a role in the binding of these drugs. Binding studies in the presence of the hydrophobic probe 1-anilinonaphthalene-8-sulfonate (ANS) showed that the binding of meloxicam and nimesulide to serum albumin involves predominantly hydrophobic interactions. Stern-Volmer analysis of the quenching data showed that quenching is highly efficient and that the tryptophan residues in hydrophobic regions of the proteins are fully exposed to the drugs. Thus these drugs are bound to albumin by hydrophobic interactions as well as hydrogen bonding at a site, which is close to the tryptophan residues. An increase of the pH and ionic strength caused an increase in the concentration of free drug, although the effect was not very significant.

Cyclooxygenase Isozymes: The Biology of Prostaglandin Synthesis and Inhibition

Nonsteroidal anti-inflammatory drugs (NSAIDs) represent one of the most highly utilized classes of pharmaceutical agents in medicine. All NSAIDs act through inhibiting prostaglandin synthesis, a catalytic activity possessed by two distinct cyclooxygenase (COX) isozymes encoded by separate genes. The discovery of COX-2 launched a new era in NSAID pharmacology, resulting in the synthesis, marketing, and widespread use of COX-2 selective drugs. These pharmaceutical agents have quickly become established as important therapeutic medications with potentially fewer side effects than traditional NSAIDs. Additionally, characterization of the two COX isozymes is allowing the discrimination of the roles each play in physiological processes such as homeostatic maintenance of the gastrointestinal tract, renal function, blood clotting, embryonic implantation, parturition, pain, and fever. Of particular importance has been the investigation of COX-1 and -2 isozymic functions in cancer, dysregulation of inflammation, and Alzheimer's disease. More recently, additional heterogeneity in COX-related proteins has been described, with the finding of variants of COX-1 and COX-2 enzymes. These variants may function in tissue-specific physiological and pathophysiological processes and may represent important new targets for drug therapy.

Pharmacokinetic profile and in vitro selective cyclooxygenase-2 inhibition by nimesulide in the dog

The pharmacokinetic properties and in vitro potency of nimesulide, a nonsteroidal anti-inflammatory drug (NSAID) were investigated in 8 or 10 dogs after intravenous (i.v.), intramuscular (i.m.) and oral (single and multiple dose) administrations at the nominal dose of 5 mg/kg. After i.v. administration, the plasma clearance was 15.3 +/- 4.2 mL/kg/h, the steady-state volume of distribution was low (0.18 +/- 0.011 L/kg) and the elimination half-life was 8.5 +/- 2.1 h. After i.m. administration, the terminal half-life was 14.0 +/- 5.3 h indicating a slow process of absorption with a maximum plasma concentration (6.1 +/- 1.5 microg/mL) at 10.9 +/- 2.1 h postadministration and the systemic bioavailability was 69 +/- 22%. After oral administration in fasted dogs, the maximal plasma concentration (10.1 +/- 2.7 microg/mL) was observed 6.1 +/- 1.6 h after drug administration, the plasma half-life was 6.2 +/- 1.9 h and the mean bioavailability was 47 +/- 12%. After daily oral administrations for 5 days, the average plasma concentration during the fifth dosage interval was 8.1 +/- 2.9 microg/mL and the overall bioavailability was 58 +/- 16%. The mean accumulation ratio was 1.27 +/- 0.4. In vitro nimesulide inhibitory potencies for cyclooxygenase (COX)-1 and COX-2 isoenzymes were determined using a whole blood assay. Canine clotting blood was used to test for inhibition of COX-1 activity and whole blood stimulated by lipopolysaccharide (LPS) was used to test for inhibition of COX-2 activity. The inhibitory concentration (IC50) for inhibition of COX-2 and COX-1 were 1.6 +/- 0.4 microM (0.49 +/- 0.12 microg/mL) and 20.3 +/- 2.8 microM (6.3 +/- 0.86 microg/mL) giving a nimesulide COX-1/COX-2 ratio of 12.99 +/- 3.41. It was concluded that at the currently recommended dosage regimen (5 mg/kg), the plasma concentration totally inhibits COX-2 and partly inhibits COX-1 isoenzyme.

Inhibition and uncoupling of oxidative phosphorylation by nonsteroidal anti-inflammatory drugs: study in mitochondria, submitochondrial particles, cells, and whole heart

The effects of the anti-inflammatory drugs diclofenac, piroxicam, indomethacin, naproxen, nabumetone, nimesulide, and meloxicam on mitochondrial respiration, ATP synthesis, and membrane potential were determined. Except for nabumetone and naproxen, the other drugs stimulated basal and uncoupled respiration, inhibited ATP synthesis, and collapsed membrane potential in mitochondria incubated in the presence of either glutamate + malate or succinate. Plots of membrane potential versus ATP synthesis (or respiration) showed proportional variations in both parameters, induced by different concentrations of nimesulide, meloxicam, piroxicam, or indomethacin, but not by diclofenac. The activity of the adenine nucleotide translocase was blocked by diclofenac and nimesulide; diclofenac also slightly inhibited mitochondrial ATPase activity. Naproxen did not affect any of the mitochondrial parameters measured. Nabumetone inhibited respiration, ATP synthesis, and membrane potential in the presence of glutamate + malate, but not with succinate. NADH oxidation in submitochondrial particles also was inhibited by nabumetone. Nabumetone inhibited O2 uptake in intact cells and in whole heart, whereas the other five drugs stimulated respiration. These observations revealed that in situ mitochondria are an accessible target. Except for diclofenac, a negative inotropic effect on cardiac contractility was induced by the drugs. The data indicated that nimesulide, meloxicam, piroxicam, and indomethacin behaved as mitochondrial uncouplers, whereas nabumetone exerted a specific inhibition of site 1 of the respiratory chain. Diclofenac was an uncoupler too, but it also affected the adenine nucleotide translocase and the H+-ATPase.

Effect of nimesulide and indomethacin on contractility and the Ca2+ channel current in myometrial smooth muscle from pregnant women

The non-steroidal anti-inflammatory drug (NSAID) indomethacin inhibits both constitutive and inducible forms of cyclo-oxygenase (COX-1 and COX-2, respectively), while nimesulide is a selective COX-2 inhibitor. Uterine COX-2 is upregulated before and during term and pre-term labour, and prostaglandins play a crucial role in parturition. We therefore evaluated the effects of these drugs on myometrial contractility and the voltage-gated Ca2+ channel current in tissue strips and isolated human myometrial smooth muscle cells (HMSMC) from myometrial biopsies taken with informed consent from women undergoing caesarean section at term (not in labour). Nimesulide and indomethacin caused almost complete inhibition of spontaneous myometrial contractions at concentrations of 100 and 300 microM, respectively. The Ca2+ channel current was inhibited in a concentration-dependent manner by both drugs, with a 40% reduction of the current at 100 microM nimesulide and 300 microM indomethacin. Nimesulide also accelerated the decay of the Ca2+ channel current. The inhibition of the Ca2+ channel current by 100 microM nimesulide and 300 microM indomethacin was unaffected by the presence of either PGF2alpha or PGE2 (30 microM), and was of similar magnitude whether 10 mM Ba2+ or 1.5 mM Ca2+ was used as the charge carrier. The concentrations of indomethacin and nimesulide required to suppress spontaneous contractility in human pregnant myometrium were much higher than those necessary to inhibit prostaglandin production. The results suggest that both nimesulide and indomethacin inhibit myometrial contractility via mechanisms independent of cyclo-oxygenase inhibition. Blockade of the Ca2+ current may contribute to this effect.

Clinical pharmacokinetics of nimesulide

Nimesulide is a selective COX-2 inhibitor used in a variety of inflammatory, pain and fever states. After healthy volunteers received oral nimesulide 100 mg in tablet, granule or suspension form the drug was rapidly and extensively absorbed. Mean peak concentrations (Cmax) of 2.86 to 6.50 mg/L were achieved within 1.22 to 2.75 hours of administration. The presence of food did not reduce either the rate or extent of nimesulide absorption. When nimesulide was administered in the suppository form, the Cmax was lower and occurred later than after oral administration; the bioavailability of nimesulide via suppository ranged from 54 to 64%, relative to that of orally administered formulations. Nimesulide is rapidly distributed and has an apparent volume of distribution ranging between 0.18 and 0.39 L/kg. It is extensively bound to albumin; the unbound fraction in plasma was 1%. The unbound fraction increased to 2 and 4% in patients with renal or hepatic insufficiency. With oral administration, the concentrations of nimesulide declined monoexponentially following Cmax. The estimated mean terminal elimination half-life varied from 1.80 to 4.73 hours. Excretion of the unchanged drug in urine and faeces is negligible. Nimesulide is largely eliminated via metabolic transformation and the principal metabolite is the 4'-hydroxy derivative (M1). Minor metabolites have been detected in urine and faeces, mainly in a conjugated form. Pharmacological tests in vivo have shown that the metabolites are endowed with anti-inflammatory and analgesic properties, although their activity is lower than that of nimesulide. Excretion in the urine and faeces accounted for 50.5 to 62.5% and 17.9 to 36.2% of an orally administered dose, respectively. The total plasma clearance of nimesulide, was 31.02 to 106.16 ml/h/kg, reflecting almost exclusive metabolic clearance. The drug has a low extraction ratio, close to 0.1. With twice daily oral or rectal administration of nimesulide, steady-state was achieved within 24 to 48 hours (2 to 4 administrations); only modest accumulation of nimesulide and M1 occurred. Gender has only a limited influence on the pharmacokinetic profiles of nimesulide and M1. The pharmacokinetic profiles of nimesulide and M1 in children and the elderly did not differ from that of healthy young individuals. Hepatic insufficiency affected the pharmacokinetics of nimesulide and M1 to a significant extent: the rate of elimination of nimesulide and M1 was remarkably reduced in comparison to the rate of elimination in healthy individuals. Therefore, a dose reduction (4 to 5 times) is required in patients with hepatic impairment. The pharmacokinetic profile of nimesulide and M1 was not altered in patients with moderate renal failure and no dose adjustment in patients with creatinine clearances higher than 1.8 L/h is envisaged. Pharmacokinetic interactions between nimesulide and other drugs given in combination [i.e. glibenclamide, cimetidine, antacids, furosemide (frusemide), theophylline, warfarin and digoxin] were absent, or of no apparent clinical relevance.

Interaction between enoxacin, a new antimicrobial, and nimesulide, a new non-steroidal anti-inflammatory agent in mice

Convulsions induced by the combination of enoxacin, a new antimicrobial, and nonsteroidal anti-inflammatory drugs including nimesulide, ketoprofen, pranoprofen and loxoprofen sodium, were investigated in mice. The oral administration of nimesulide alone induced clonic convulsions at more than 300 mg/kg. The oral administration of ketoprofen, pranoprofen or loxoprofen sodium induced no convulsion up to 1000 mg/kg, 500 mg/kg and 600 mg/kg, respectively, and that of enoxacin induced no convulsion at more than 5000 mg/kg. The combination of nimesulide at 200 mg/kg and enoxacin at 400 mg/kg induced no convulsion. In contrast, the combination of enoxacin at 100 mg/kg and either ketoprofen at 125 mg/kg or pranoprofen at 500 mg/kg induced clonic convulsions, while that of enoxacin at 400 mg/kg and loxoprofen sodium at 600 mg/kg induced no convulsion. These results suggest that the combination of nimesulide and enoxacin may possibly induce few or less convulsions in the clinical setting.

Characterization of binding sites, extent of binding, and drug interactions of oligonucleotides with albumin

Phosphorothioate oligonucleotides (S-ODNs) have the ability to modulate gene expression selectively and thus have potential therapeutic capabilities. This potential led us to investigate the protein binding characteristics of selected S-ODNs. We evaluated S-ODN interactions with bovine serum albumin (BSA) and human serum albumin (HSA) in vitro. The equilibrium dissociation constants Km for the binding of a 20 mer S-ODN with BSA and HSA range between 1.1-5.2 x 10(-5) and 2.4-3.1 x 10(-4) M, respectively. The Km for an unrelated 15 mer S-ODN binding with HSA ranges between 3.7 and 4.8 x 10(-5) M. Studies with a fluorescently labeled 27 mer S-ODN suggest cooperative binding (Hill slope = 1.67) and/or the presence of secondary binding sites on the S-ODN. HSA or BSA linked to Sepharose was incubated with a 15, 20, or 24 mer S-ODN followed by the addition of selected drugs known to be highly protein bound (nifedipine, warfarin, midazolam, probenecid, indomethacin, and mitoxantrone). Up to 30% of S-ODN was displaced by warfarin in competition binding assays. Conversely, HSA-bound warfarin was incubated with a variety of oligonucleotides, including RNA and genomic dsDNA. Maximum displacement of warfarin-bound HSA was observed following incubation with 5'-cholesterol-conjugated 20 mer S-ODN. In summary, S-ODNs are likely to interact and displace other therapeutic agents that bind to albumin, particularly those binding at site I.

Drug interactions with nimesulide

Nimesulide is a recently developed analgesic, antipyretic and anti-inflammatory agent that differs from conventional nonsteroidal anti-inflammatory drugs both in structure and pharmacological profile. Since nimesulide may be prescribed for patients receiving concomitant medication, the propensity for drug interactions exists. Investigations have been conducted to assess the potential for pharmacokinetic and pharmacodynamic interaction. With regard to absorption, there is some evidence that nimesulide may decrease the oral bioavailability of furosemide (frusemide). Nimesulide is extensively bound to plasma proteins and may be displaced from binding sites by concurrently administered drugs such as fenofibrate, salicylic acid and tolbutamide. In addition, nimesulide may displace salicylic acid and furosemide (but not warfarin) from plasma proteins. Major interactions involving interference with drug metabolism have not been described with nimesulide. A marginal decrease in plasma theophylline levels (without changes in respiratory function tests) has been described after addition of nimesulide to chronic theophylline therapy. Despite earlier suggestions that nimesulide may increase the hypoglycaemic effect of glibenclamide, a formal study excluded any influence of the drug on fasting blood sugar and glucose tolerance in diabetic patients treated with various sulfonylureas. Although nimesulide does not usually affect the response to warfarin, a few patients may show some increase in anticoagulant effect; therefore, it would seem prudent to monitor coagulation status when the 2 drugs are administered together. Finally, nimesulide may reduce the natriuretic response to furosemide and potentiate the furosemide-induced reduction in glomerular filtration rate and renal blood flow, through a pharmacodynamic interaction which is likely to involve inhibition of renal cyclo-oxygenase. These results suggest that caution should be exercised when nimesulide is used in combination with drugs that are known to adversely affect renal haemodynamics.