Variability in response to NSAIDs. Fact or fiction?

Honorary Professor Garry Graham

An appreciation of the contribution of Professor Gary Graham to anti-inflammatory and antirheumatic pharmacology and clinical pharmacology.

Cost-effectiveness analyses of osteoarthritis oral therapies: a systematic review

BACKGROUND

Cost-effectiveness analyses (CEAs) have been performed for oral non-disease-altering osteoarthritis (OA) treatments for well over a decade. During that period the methods for performing these analyses have evolved as pharmacoeconomic methods have advanced, new treatments have been introduced, and the knowledge of associated adverse events (AEs) has improved.

OBJECTIVE

The objective of this systematic review was to trace the development of CEAs for oral non-disease-altering treatments in OA.

METHODS

A systematic search for CEAs of OA oral treatments was performed of the English-language medical literature using the following databases: PubMed, EMBASE, MEDLINE In-Process, EconLit, and Cochrane. Key requirements for inclusion were that the population described patients with OA or arthritis and that the analysis reported at least one incremental cost-effectiveness ratio. Each identified publication was assessed for inclusion. Thirteen characteristics and all AEs appearing in each included CEA were extracted and organized. Reference lists from these CEAs were also searched. A chronology of key CEAs in the field was compiled, noting the characteristics that advanced the state of the art in modeling oral OA treatments.

RESULTS

Thirty publications of 28 CEAs were identified and evaluated. Developments in CEAs included an expanded set of comparators that broadened from non-steroidal anti-inflammatory drugs (NSAIDs) only to NSAIDs plus gastroprotective agents, cyclooxygenase-2 inhibitors, and opioids. In turn, AEs expanded from gastrointestinal (GI) events to also include cardiovascular (CV) and neurological events. Efficacy, which initially was presumed to be equivalent for all treatments, evolved to treatment-specific efficacies. Decision-tree analyses were generally replaced by Markov models or, occasionally, stochastic or discrete event simulation. Finally, outcomes have progressed from GI-centric measures to also include quality-adjusted life-years.

CONCLUSION

Methods used by CEAs of oral non-disease-altering OA treatments have evolved in response to changing treatments with different safety profiles and efficacies as well as technical advances in the application of decision science to health care.

[Pharmacological management of inflammatory rheumatic conditions]

Inflammatory rheumatic disorders are related to different pathophysiological mechanisms and, hence, their therapeutic management varies according to the underlying disease. Crystal-induced arthritis is characterized by its almost specific responsiveness to colchicine. Regarding ankylosing spondylitis, non steroidal anti-inflammatory drugs (NSAIDs) and TNF blockers are the cornerstones of pharmacological intervention whereas oral corticosteroids at conventional doses are of little value, if any. Conversely, corticosteroids are the drug of choice to treat polymyalgia rheumatica. Furthermore, low-dose corticosteroids were shown to be more effective than NSAIDs in patients with rheumatoid arthritis (RA). However, the main goal being to achieve remission, disease-modifying antirheumatic drugs, either synthetic, especially methotrexate, and/or biologic, such as TNF inhibitors, have a major role in the management of RA. Finally, enhanced understanding of molecular pathogenesis of inflammatory disorders may help to find out how to best target available drugs to right individuals in the future.

Patient satisfaction with arthritis medication

Patient derived information to support the long term use of non-steroidal anti-inflammatory drugs (NSAIDs) is lacking. In contrast, data detailing the adverse effects of individual NSAIDs is accumulating. We determined the importance of NSAIDs as therapy to 153 patients with osteoarthritis (age range 36 to 92), comparing results in elderly and younger patients. Around half of the patients reported moderate relief of symptoms, with a further quarter reporting good, or even excellent, relief. One half of patients aged 75 years or less, but only one fifth of patients aged over 75 years, recalled having been informed of the adverse effects of NSAIDs. A total of 59 per cent of patients reported having used simple analgesics, such as paracetamol, as first line therapy. As some patients are helped by them, we suggest that efforts should be directed towards increasing the first line use of simple analgesics in patients with osteoarthritis and towards increasing patient awareness of potential NSAID-related adverse effects.

Progress in genetic studies of pain and analgesia

Interindividual variability in pain sensitivity and the response to analgesic manipulations remains a considerable clinical challenge as well as an area of intense scientific investigation. Techniques in this field have matured rapidly so that much relevant data have emerged only in the past few years. Our increasing understanding of the genetic mediation of these biological phenomena have nonetheless revealed their surprising complexity. This review provides a comprehensive picture and critical analysis of the field and its prospects.

Failures in a proton pump inhibitor therapeutic substitution program: lessons learned

The pathogenesis of patient dissatisfaction following involuntary therapeutic substitutions involving proton pump inhibitors (PPIs) is poorly understood. The aim of this study was to describe the patient population experiencing therapeutic failure and investigate whether failure was related to individual differences in response to the different PPIs. Treatment failures in a lansoprazole-rabeprazole therapeutic substitution program were compared to switch successes. A subgroup was randomized in a double-blind, double-dummy, crossover study to four 2-week periods of lansoprazole-rabeprazole-lansoprazole-rabeprazole or vice versa. Measures included overall rating of gastrointestinal reflux disease (GERD) symptoms for the past week as well as the frequency and distress scales of the GERD Symptom Assessment Scale. One hundred fifteen nonresponders were compared with 54 successful responders. Nonresponders consisted primarily of patients with GERD (74%, vs. 44% of responders; P = 0.005) who had undergone upper gastrointestinal endoscopy (50%, vs. 31% of responders; P = 0.02). Twelve patients completed the randomized treatment study. The interrater kappa coefficient for responder status was estimated to be 0.80 for lansoprazole and 0.21 for rabeprazole. The majority of PPI nonresponders had a clinical diagnosis of GERD and were receiving >/=40 mg of rabeprazole daily. This pilot study provides new insights into the design of subsequent studies of nonresponders in PPI therapeutic substitution programs.

WITHDRAWN: Analgesia and non-aspirin, non-steroidal anti-inflammatory drugs for osteoarthritis of the hip

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) have been widely used as a pharmacologic treatment to relieve pain for patients with OA of the hip. However, these agents are associated with significant toxicity, particularly in the elderly population (age > 65 years).

OBJECTIVES

To review all randomized trials of analgesics and anti-inflammatory therapy in osteoarthritis (OA) of the hip. To determine which non-steroidal, anti-inflammatory drug (NSAID) is the most effective, and which NSAID is the most toxic.

SEARCH STRATEGY

We searched the Cochrane Musculoskeletal Group's trials register, the Cochrane Controlled Trials Register and MEDLINE up to August 1994. Reference lists of all trials were also manually searched.

SELECTION CRITERIA

All randomized controlled trials comparing non-steroidal anti-inflammatory drugs (NSAIDs) and/or analgesics in patients with Osteoarthritis. The trials selected for inclusion were identified by one reviewer (TT) and rechecked by a second (MH).

DATA COLLECTION AND ANALYSIS

Qualitative assessments were performed using a quality scoring system designed for NSAID trials in rheumatoid arthritis. Both the design and analysis aspects of the trials were evaluated, each aspect being rated on a scale of 0 to 8. A quantitative method, which calculates the ratio of improvement produced by one NSAID to that produced by another, was used to rate the relative efficacy of different NSAIDs with respect to pain relief. Toxicity comparisons were made according to the reviewer findings. All quality assessments were carried out independently by two reviewers (TT, BS). All data abstraction was carried out by one reviewer (TT) and rechecked by two other reviewers (BS, GW). A consensus was reached on discrepancies.

MAIN RESULTS

Forty-three trials were identified, and of these, 39 evaluated NSAIDs, while four evaluated only analgesics. The median design and analysis scores were two and four respectively. Six NSAIDs were included in at least five trials. Of these, indomethacin was rated more effective in five of its seven comparisons, but more toxic in seven of 12 comparisons. Only five of the 29 (17%) NSAID comparisons found statistically significant differences in efficacy. Of the 43 RCTs identified only 17 had statistical data available for future pooling for this meta-analysis. In the case where data was missing, authors of the trials will be contacted for inclusion of data in future reviews.

AUTHORS' CONCLUSIONS

NSAID trials in patients with OA of the hip appear to be weakened by the lack of standardization of case definition of OA, and also by the lack of standardization of outcome assessments. No clear recommendations for the choice of specific NSAID therapy in hip OA can be offered at this time based on this analysis.

Anti-inflammatory and antioxidant activity of coumarins designed as potential fluorescent zinc sensors

A series of coumarin analogs, designed and synthesised as potential fluorescent zinc probes were evaluated for their biological activity as anti-inflammatory and antioxidant agents. The effect of the synthesised compounds on inflammation, using the carrageenin-induced rat paw oedema model, was studied. In general, the compounds were found to be potent anti-inflammatory agents (26.5-64%). Compound 5 was found to interact significantly with 1,1-diphenyl-2-picryl-hydrazyl stable free radical (DPPH) whereas the remainder were inactive in this assay. The compounds inhibit in general the soybean lipoxygenase and scavenge superoxide anion radicals. The anti-inflammatory activity seems to be connected with their reducing activity. Their RM values were determined as an expression of their lipophilicity. Theoretical calculations of their lipophilicity as clog P were performed indicating that only a poor relationship exists between their lipophilicity and anti-inflammatory activity.

Synthesis and pharmacochemical study of new Cu(II) complexes with thiophen-2-yl saturated and alpha,beta-unsaturated substituted carboxylic acids

Copper complexes with thiophen-2-yl saturated and alpha,beta-unsaturated carboxylic acids as ligands were prepared, characterized and pharmacochemically studied. The available evidence supports a dimeric structure for the complexes of the general formula [Cu2(L)4(MeOH)2] where L are the anions of thiophene 2-carboxylic acid (HL1), 2-(thiophen-2-yl)-acetic acid (HL2), 3-thiophen-2-yl-acrylic acid (HL3), 2-phenyl-3-thiophen-2-yl-acrylic acid (HL4) respectively. The crystal structure of [Cu2(L1)4(MeOH)2] (2) was determined while preliminary X-ray analysis of the copper complex with L4 isolated from MeOH/DMSO solution proved to contain three crystallographically independent dimers of the formula [Cu2(L4)4(MeOH)(dmso)][Cu2(L4)4(MeOH)2][Cu2(L4)4(dmso)2].8MeOH (9). Since lipophilicity is a significant physicochemical property determining distribution, bioavailability, metabolic activity and elimination, we tried to measure experimentally their lipophilicity from RPTLC method. The copper complexes and the ligands (thiophen-2-yl saturated and alpha,beta-unsaturated carboxylic acids) were tested in vitro on: (a) soybean lipoxygenase inhibition, (b) interaction with 1,1-diphenyl-2-picryl-hydrazyl (DPPH) stable free radical, (c) the HO* mediated oxidation of DMSO, (d) inhibition of lipid peroxidation, (e) scavenging of superoxide anion radicals and in vivo for the inhibition of carrageenin-induced rat paw edema. The compounds have shown important antioxidant activity, significant anti-inflammatory activity and potent inhibition of soybean lipoxygenase as a result of their physichochemical features. Complex [Cu2(L1)4(MeOH)2] (2) presents the higher in vivo activity (77.4%) followed by complex [Cu2(L2)4(MeOH)2] (4) (51%). Both complexes are more potent anti-inflammatory agents compared to their respective ligands. Moreover we have performed in vitro studies upon their effect on dsDNA, using adsorptive transfer stripping voltammetry and a dsDNA modified carbon paste electrode. Our conclusions were mainly based upon the effect of the studied compounds on the oxidation signal of guanine and adenine. From the given data it seems that complexes show similarities in their behaviour.

Evaluation of anti-inflammatory and antioxidant activities of mixed-ligand Cu(II) complexes of dien and its Schiff dibases with heterocyclic aldehydes and 2-amino-2-thiazoline

A new series of complexes of the type [Cu(dien)(2a-2tzn)Y2] and [Cu(dienXX)(2a-2tzn)Y2] has been tested for anti-inflammatory and antioxidant activity. The tested compounds inhibit significantly the carrageenin induced paw edema (36.4-55.8%) and present important scavenging activities. Although their interaction with the free stable radical DPPH is not high they peroxide anions. Compound 7 is the most potent (55.8%) in the in vivo experiment. Lipophilicity--as RM values and theoretically calculated logP values--has been determined. An attempt to correlate the biological results with their structural characteristics and physicochemical parameters has been done.

Synthesis and biological evaluation of new thiazolyl/benzothiazolyl-amides, derivatives of 4-phenyl-piperazine

A series of thiazolyl-N-phenyl piperazines has been synthesised and tested for anti-inflammatory activity. Their R(M) values were determined as an expression of their lipophilicity. Theoretical calculation of their lipophilicity, as clog P and logPsk also performed. The effect of the synthesised compounds on inflammation, using the carrageenin induced mouse paw oedema model was studied. In general, the studied compounds were found to be potent anti-inflammatory agents (44-74.1%). Anti-inflammatory activity was influenced by some structural characteristics of the synthesised compounds. An attempt was made to correlate their biological activity with some physicochemical parameters using a quantitative structure-activity relationship approach (QSAR).

Relationships Between the Concentrations of Prostaglandins and the Nonsteroidal Antiinflammatory Drugs Indomethacin, Diclofenac, and Ibuprofen

STUDY OBJECTIVES

To study the concentration-effect relationships of the nonsteroidal antiinflammatory drugs (NSAIDs) indomethacin, diclofenac, and ibuprofen; to investigate whether standard doses of these drugs inhibit prostaglandin concentrations to a similar extent, determined by measuring the concentration of a surrogate marker of prostaglandin E 2 (PGE 2 ); and to determine the extent to which dose increases produce analogous increases in prostaglandin inhibition.

DESIGN

Single-dose, randomized, crossover trial with a 1-week washout period.

SETTING

University biopharmaceutics and pharmacokinetics laboratory.

SUBJECTS

Eight healthy adult volunteers younger than 35 years old.

INTERVENTION

Subjects were administered two different standard doses of regular formulations (not enteric coated) of each NSAID on separate occasions.

MEASUREMENTS AND MAIN RESULTS

Plasma samples were collected for determination of drug and 13,14-dihydro-15-keto-PGE 2 (PGEM; the surrogate marker of PGE 2 ) concentrations at regular intervals after administration of each NSAID dose. Statistically significant linear correlations were found between the percent reduction in PGEM concentration and the concentrations of diclofenac, indomethacin, and ibuprofen in plasma (R 2 = 0.992-0.999). The PGEM plasma concentrations correlated inversely with NSAID plasma concentrations, indicating maximum inhibition when the highest NSAID plasma concentrations were achieved. Statistically significant differences in the percent inhibition of PGEM concentrations were observed between the two doses for each NSAID (p<0.05), but not between subjects for each NSAID. Doubling the dose (100% increase) of diclofenac and indomethacin produced a 60-65% increase in maximum inhibition of PGEM concentrations, whereas a 50% increase in dose produced a 44% increase in the maximum effect of ibuprofen.

CONCLUSION

Prostaglandin inhibition, as measured by changes in PGEM concentrations, correlated significantly with NSAID concentrations in plasma and differed significantly between high and low NSAID doses. Measurement of PGEM plasma concentrations appears to be a promising marker for estimation of relative potency of NSAIDs.

Study of usage pattern of nonsteroidal anti-inflammatory drugs (NSAIDs) among different practice categories in Indian clinical setting

OBJECTIVE

The aim of the study was to evaluate the usage pattern of nonsteroidal anti-inflammatory drugs (NSAIDs) in diverse clinical practice settings in India.

METHODS

The study was conducted in Mumbai city and its suburbs, involving 1,916 doctors from among general practice to specialist practice. The data were collected with the help of a semi-structured questionnaire and were analysed statistically to bring out differences in NSAID usage among different groups of prescribers.

RESULTS

All the 1,916 doctors prescribed NSAIDs frequently with prescriptions ranging from 1 to 15 daily; they short-listed and prescribed only two to five NSAIDs from among a plethora of drugs available including fixed-dose combinations (FDCs). It is significant that FDCs were prescribed by more than 39% of doctors in all the categories, the highest prescribers being orthopaedic surgeons (76%) and lowest general practitioners (GPs; 39%). Apart from recommended usage, NSAIDs such as ibuprofen, diclofenac and aspirin were used for pelvic inflammatory disease, and indomethacin for pre-term labour and patent ductus arteriosus. Dosage variation, both in terms of dose and frequency of administration, has been observed for several NSAIDs in the GPs category as well as in the specialist categories-except that of paediatricians. In patients suffering from bronchial asthma, there has been significant use of aspirin and ibuprofen by GPs despite contra-indication for their use in such patients. Most prescribers perceived that NSAIDs are associated with mild gastrointestinal (GI) adverse events. Ibuprofen, a drug with reportedly better gastric tolerance, was perceived to cause GI adverse events, though to a lesser extent than aspirin; fewer prescribers perceived that diclofenac and piroxicam cause GI adverse events when compared with aspirin and ibuprofen. There were significant differences among the five practice categories with regard to preferences for NSAIDs. The first choice NSAIDs were ibuprofen, aspirin, diclofenac, paracetamol, piroxicam and ibuprofen+paracetamol FDC.

CONCLUSIONS

This study has shown that there exist significant differences in the usage pattern and preferences of NSAIDs among different practice categories in India. The data have also revealed that there is a need for awareness programmes on rational prescribing of NSAIDs towards optimal therapeutics and improved patient care in India.

Synthesis and biological evaluation of novel coumarin derivatives with a 7-azomethine linkage

The synthesis of several novel coumarin derivatives with a 7-azomethine linkage was carried out starting from 7-formyl-coumarin. The compounds were tested in vivo for their anti-inflammatory activity and in vitro for their antioxidant ability. Compounds 3a and 3e possess significant protection against carrageenin induced rat paw edema.

The heritability of antinociception II: pharmacogenetic mediation of three over-the-counter analgesics in mice

Chromosomal loci containing genes affecting antinociceptive sensitivity to morphine have been identified, but virtually nothing is known about the genetic mediation of sensitivity to over-the-counter analgesics. Such knowledge would be of great clinical interest, as prodigious interindividual variability has been noted in the efficacy of these ubiquitously used drugs. In the present study, we assessed heritability and genetic correlations among three over-the-counter analgesics in mice of 12 inbred mouse strains on the 0.9% acetic acid (i.p.) writhing test. Analgesics included the centrally acting analgesic, acetaminophen (150 mg/kg, s.c.), and the nonsteroidal anti-inflammatory drugs (NSAIDs), indomethacin (40 mg/kg, s.c.) and lysine-acetylsalicylic acid (800 mg/kg, s.c.). Significant strain differences in sensitivity to each of the drugs were observed, with narrow-sense heritability estimates ranging from 23 to 45%. Similar strains were sensitive and resistant, respectively, to the two NSAIDs (r(s) = 0.64). In contrast, a completely different pattern of sensitivities was observed for acetaminophen, implying genetic dissociation (r(s) = 0.29 and 0.02) compared with the NSAIDs. Additional experiments were performed on two strains, C57BL/6 and DBA/2, with extreme sensitivities to acetaminophen. Plasma acetaminophen levels in these strains were not significantly different during the time of antinociception assessment, suggesting the existence of genetic factors affecting acetaminophen pharmacodynamics rather than pharmacokinetics.

Choosing the right nonsteroidal anti-inflammatory drug for the right patient: a pharmacokinetic approach

Effective use of the growing number of nonsteroidal anti-inflammatory drugs (NSAIDs), a group that has recently been augmented by the introduction of the selective cyclo-oxygenase-2 inhibitors, requires adequate knowledge of their pharmacokinetics. After oral administration, the absorption of NSAIDs is generally rapid and complete. NSAIDs are highly bound to plasma proteins, specifically to albumin (>90%). The volume of distribution of NSAIDs is low, ranging from 0.1 to 0.3 L/kg, suggesting minimal tissue binding. NSAID binding in plasma can be saturated when the concentration of the NSAID exceeds that of albumin. Most NSAIDs are metabolised by the liver, with subsequent excretion into urine or bile. Enterohepatic recirculation occurs when a significant amount of an NSAID or its conjugated metabolites are excreted into the bile and then reabsorbed in the distal intestine. NSAID elimination is not dependent on hepatic blood flow. Hepatic NSAID elimination is dependent on the free fraction of NSAID within the plasma and the intrinsic enzyme activities of the liver. Renal elimination is not an important elimination pathway for NSAIDs, except for azapropazone. The plasma half-life of NSAIDs ranges from 0.25 to >70 hours, indicating wide differences in clearance rates. Hepatic or renal disease can alter NSAID protein binding and metabolism. Some NSAIDs with elimination predominantly via acylglucuronidation can have significantly altered disposition. Pharmacokinetics are also influenced by chronobiology, and many NSAIDs exhibit stereoselectivity. There appear to be relationships between NSAID concentration and effects. At therapeutically equivalent doses, NSAIDs appear to be equally efficacious. The major differences between NSAIDs are their therapeutic half-lives and safety profiles. NSAIDs undergo drug interactions through protein binding displacement and competition for active renal tubular secretion with other organic acids. When choosing the right NSAID for the right patient, individual patient-specific and NSAID-specific pharmacokinetic principles should be considered.

Analgesia and non-aspirin, non-steroidal anti-inflammatory drugs for osteoarthritis of the hip

OBJECTIVES

To review all randomized trials of analgesics and anti-inflammatory therapy in osteoarthritis (OA) of the hip. To determine which non-steroidal, anti-inflammatory drug (NSAID) is the most effective, and which NSAID is the most toxic.

SEARCH STRATEGY

We searched the Cochrane Musculoskeletal Group's trials register, the Cochrane Controlled Trials Register and Medline up to August 1994. Reference lists of all trials were also manually searched.

SELECTION CRITERIA

All randomized controlled trials comparing non-steroidal anti-inflammatory drugs (NSAIDs) and/or analgesics in patients with Osteoarthritis. The trials selected for inclusion were identified by one reviewer (TT) and rechecked by a second (MH).

DATA COLLECTION AND ANALYSIS

Qualitative assessments were performed using a quality scoring system designed for NSAID trials in rheumatoid arthritis. Both the design and analysis aspects of the trials were evaluated, each aspect being rated on a scale of 0 to 8. A quantitative method, which calculates the ratio of improvement produced by one NSAID to that produced by another, was used to rate the relative efficacy of different NSAIDs with respect to pain relief. Toxicity comparisons were made according to the reviewer findings. All quality assessments were carried out independently by two reviewers (TT, BS). All data abstraction was carried out by one reviewer (TT) and rechecked by two other reviewers (BS, GW). A consensus was reached on discrepancies.

MAIN RESULTS

Forty-three trials were identified, and of these, 39 evaluated NSAIDs, while four evaluated only analgesics. The median design and analysis scores were two and four respectively. Six NSAIDs were included in at least five trials. Of these, indomethacin was rated more effective in five of its seven comparisons, but more toxic in seven of 12 comparisons. Only five of the 29 (17%) NSAID comparisons found statistically significant differences in efficacy. Of the 43 RCTs identified only 17 had statistical data available for future pooling for this meta-analysis. In the case where data was missing, authors of the trials will be contacted for inclusion of data in future reviews.

REVIEWER'S CONCLUSIONS

NSAID trials in patients with OA of the hip appear to be weakened by the lack of standardization of case definition of OA, and also by the lack of standardization of outcome assessments. No clear recommendations for the choice of specific NSAID therapy in hip OA can be offered at this time based on this analysis.

The use of analgesics in the management of pain in rheumatic diseases

Pain is the most common complaint of patients who see rheumatologists. In this article, the current treatment options for pain are reviewed; these include acetaminophen, nonsteroidal anti-inflammatory drugs, new specific cyclooxygenase-2 inhibitors, opioid analgesics, centrally acting muscle relaxants, antidepressants, and topical analgesics and counterirritants. The doses of medication and known adverse effects of these medications are highlighted.

Is genetics the unrecognized confounding factor in bioelectromagnetics? Flock-dependence of field-induced anoxia protection in chick embryos

Work in bioelectromagnetics has long been plagued by problems with replication. This includes experiments done on electromagnetic (EM) field-induced effects in chick embryos. Our laboratory investigated responses of embryos from two flocks of White Leghorn hens. Both flocks were studied simultaneously, and it was found that they responded differently to EM field exposures. Embryos were exposed to 60 Hz, 8 microT EM fields prior to placement in an anoxic chamber. Following re-oxygenation, survival in controls was 34.6%, exposed flock 1 survival was 62% (P < 0.0001) and exposed flock 2 survival was 43% (P < 0.0136). P values are from comparison of data between EM field exposed embryos (flocks 1 and 2) versus controls. In order to induce maximum protection in flock 2, (approximately 62% survival), embryos required a longer exposure time at higher magnetic field strengths. These results reinforce the concepts that genetics are important in determining whether or not chick embryos will respond to EM field stimulation. A broader look at the role of genetic factors emphasizes that these variations in response to external stimuli (e.g., drugs, radiation, and EM fields) are found in all areas of biological research (cell culture, chick, rat, and human studies). The present study suggests that genetics may be a prime cause of the difficulties encountered in replication studies in the field of bioelectromagnetics. We conclude that replication studies should not be undertaken unless care is taken to insure that exactly the same strains of cells or animals are used. Researchers should also first confirm that the responses of their model to non-EM field stimuli are similar to that obtained in the original study.

Clinical pharmacokinetics of naproxen

Naproxen is a stereochemically pure nonsteroidal anti-inflammatory drug of the 2-arylpropionic acid class. The absorption of naproxen is rapid and complete when given orally. Naproxen binds extensively, in a concentration-dependent manner, to plasma albumin. The area under the plasma concentration-time curve (AUC) of naproxen is linearly proportional to the dose for oral doses up to a total dose of 500 mg. At doses greater than 500 mg there is an increase in the unbound fraction of drug, leading to an increased renal clearance of total naproxen while unbound renal clearance remains unchanged. Substantial concentrations of the drug are attained in synovial fluid, which is a proposed site of action for nonsteroidal anti-inflammatory drugs. Relationships between the total and unbound plasma concentration, unbound synovial fluid concentration and therapeutic effect have been established. Naproxen is eliminated following biotransformation to glucuroconjugated and sulphate metabolites which are excreted in urine, with only a small amount of the drug being eliminated unchanged. The excretion of the 6-O-desmethylnaproxen metabolite conjugate may be tied to renal function, as accumulation occurs in end-stage renal disease but does not appear to be influenced by age. Hepatic disease and rheumatoid arthritis can also significantly alter the disposition kinetics of naproxen. Although naproxen is excreted into breast milk the amount of drug transferred comprises only a small fraction of the maternal exposure. Significant drug interactions have been demonstrated for probenecid, lithium and methotrexate.

Treatment of rheumatoid arthritis

The management of rheumatoid arthritis (RA) remains a challenging objective. Recent trends have led to the earlier and more "aggressive" treatment of patients with active disease. This change in outlook is largely the result of the recognition that significant damage can occur fairly soon after the onset of disease. This article reviews the currently available therapies, including a discussion of the benefits and side effects associated with individual agents. In addition, possible approaches to the treatment of RA will be reviewed.

Non-steroidal anti-inflammatory agents, Part 20. Method for testing non-steroidal anti-inflammatories: the modified hen's egg chorioallantoic membrane test (HET-CAM test) compared to other procedures

The delay of onset of irritation phenomena at the chorioallantoic membrane of incubated hen's eggs, a parameter for anti-inflammatory activity, was determined for the pharmaceutical substances diclofenac, flufenamic acid, ibuprofen, indomethacin, ketoprofen, piroxicam, phenylbutazone, salicylic acid, and sodium salicylate. Alongside questions relating to the dose-effect ratio, metabolisation, recovery, and diffusion of the substances to their site of action were investigated. The reproducibility of the procedure and its selectivity with regard to substances with a different mechanism of action is proven. The method allows classification of the substances according to their anti-inflammatory potency. However, correlation with the results of enzyme inhibition or in vivo results is only possible to a limited extent.

Variability in the stereoselective disposition of ibuprofen in patients with rheumatoid arthritis

1. Patients suffering from rheumatoid arthritis received oral doses of 600 mg racemic ibuprofen (n = 25; RAC) or 400 mg (S)-ibuprofen (n = 25; S-IBU) in a double-blind, randomized parallel-group study. 2. The pharmacokinetic parameters of (S)-ibuprofen were not statistically different between treatments (P > 0.05). Comparing (S)- and (R)-ibuprofen within the group receiving the racemate significantly higher Cmax (20.3 +/- 5.3 vs 17.7 +/- 4.4 micrograms ml-1; P < 0.02; 95% confidence interval for differences (CI): 0.5-4.6), AUC (86.2 +/- 23.5 vs 67.6 +/- 26.6 micrograms ml-1 h; P < 0.001; CI: 9.5-27.6), mean residence time (4.5 +/- 1.1 vs 4.1 +/- 1.2 h; P < 0.01; CI: 0.1-0.6) and renal clearance (0.8 +/- 0.6 vs 0.0 +/- 0.0 ml min-1; P < 0.001; CI: 0.5-1.0) values were observed for the (S)-enantiomer. 3. No difference was found (P > 0.05) between treatments in the percentage of the dose recovered in the urine as (R)- or (S)-ibuprofen plus metabolites (S-IBU: 80.2 +/- 8.47 vs RAC: 74.1 +/- 14.0%). 4. Interindividual variation in the pharmacokinetics of (S)-ibuprofen following administration of the racemate was similar to that following the administration of the single isomer suggesting that chiral inversion is not a major factor contributing to variability in the disposition of this drug.

Do the pharmacodynamics of the nonsteroidal anti-inflammatory drugs suggest a role in the management of postoperative pain?

Until recently, nonsteroidal anti-inflammatory drugs (NSAIDs) were regarded as weak analgesic agents with a potent antiplatelet effect that severely limited their perioperative usefulness. However, the recent development of injectable NSAIDs has stimulated a re-evaluation of the potential role of this class of drugs in postoperative pain management. In general surgery, NSAIDs have been shown to be effective analgesics when administered after surgery, as judged by either a reduction in pain scores and/or by an opioid sparing effect. Parenteral NSAIDs alone, notably ketorolac and diclofenac, may be adequate or even preferred analgesic agents after minor surgery. In dental surgery, NSAIDs produce greater initial analgesia than steroids, although the latter produce greater suppression of swelling and less functional loss. NSAID pretreatment results in only modest suppression of swelling compared with placebo. These data suggest that the acute analgesic effects of NSAIDs in oral surgery and probably other models result from suppression of a nociceptive process, rather than a generalised anti-inflammatory effect. This view challenges the traditional association between inhibition of prostaglandin synthesis and the therapeutic effects of these drugs. The variety of NSAIDs leads to a range in half-lives from short, e.g. diclofenac (1 h), intermediate, e.g. ketorolac (5h), to long, e.g. tenoxicam (60h), which has implications for both convenience of the dosage regimen and drug accumulation. For some racemic NSAIDs (e.g. ibuprofen), metabolic 'activation' of the inactive R-enantiomer to the active S-enantiomer occurs. Renal dysfunction may increase both the plasma concentration and body residence time of NSAIDs, thereby increasing the risk of adverse effects. The concomitant effects of anaesthesia have not yet been studied. The principal concern regarding the use of perioperative NSAIDs is the risk of decreased haemostasis and wound healing. Although it has been found that NSAIDs prolong bleeding times in patients, values generally remain below the upper limits of those in generally healthy patients. Healing of gastrointestinal anastomoses may be compromised by NSAID administration but corneal healing and bone remodelling are not. There is a need for further research into the potential for renal side effects with NSAIDs in the perioperative setting, where the effects of anaesthesia and surgery may increase the risk of side effects, particularly in elderly patients. The main benefits of NSAIDs derive from opioid sparing (e.g. reduction in perioperative nausea and vomiting and improvement in ventilation), although some studies allude to an enhanced quality of analgesia from the combination compared with either NSAID or opioid alone. The question of pre- vs postinjury treatment with NSAIDs remains unresolved.

The problems and pitfalls of NSAID therapy in the elderly (Part II)

The elderly are most susceptible to pharmacokinetic drug interactions between various NSAIDs and anticoagulants, sulphonylurea hypoglycaemic agents, certain anticonvulsants, methotrexate, digoxin, aminoglycosides and lithium. Pharmacodynamic interactions between some NSAIDs and antihypertensive drugs, anticoagulants, sulphonylurea agents and other NSAIDs are also potentially significant in the elderly. Despite the finding that mean therapeutic responses of large groups of patients have been generally equivalent for the wide range of NSAIDs studied thus far, it is also apparent that marked variability exists in the response of individual patients to different NSAIDs. Subsequent dosage increments may predispose 'nonresponders' and some less sensitive 'responders' to toxicity from NSAIDs. This interindividual variability in response to NSAIDs may be contributed to by the differing physicochemical properties of NSAIDs, physician prescribing habits and patient expectations, variations in NSAID pharmacokinetics, and the differing effects of NSAIDs other than their common ability to inhibit prostaglandin synthesis. The principles for drug prescribing in the elderly are no different from those that should be applied to the prescribing of medication in any patient. The clinician should strive to make a diagnosis and should avoid treating symptoms in isolation. Critical assessment of the indication for prescribing NSAID therapy must include consideration of the available effective and safe alternatives. If an NSAID is commenced the lowest effective dose should be the desired goal, but after an appropriate trial it is acceptable clinical practice to employ an alternative NSAID. There is no justification for combination NSAID therapy. The progress of each patient must be carefully monitored, particularly during the first few months of treatment, while periodic review of the ongoing need for the NSAID is essential.

Interactions between non-steroidal anti-inflammatory drugs and H2-receptor antagonists or prostaglandin analogues

Published pharmacokinetic studies investigating possible interaction between H2-receptor antagonists (n = 22) or prostaglandin analogues (n = 6) and nonsteroidal anti-inflammatory drugs (NSAIDs) have been reviewed. With two exceptions the studies were carried out in young, healthy male volunteers rather than in arthritis patients. In addition some of the studies were poorly designed and inadequately described. Cimetidine appeared to increase the area under the plasma concentration-time curve, and hence to decrease the apparent oral clearance, of several NSAIDs including piroxicam, indomethacin, flurbiprofen, sulindac, oxaprozin and aspirin, while ranitidine co-administration resulted in similar changes for oxyprozin alone. The data currently available for prostaglandin analogues are insufficient to draw firm conclusions. It therefore remains a possibility that clinically relevant pharmacokinetic interactions may occur in elderly arthritic patients, and this issue needs to be addressed.

Pharmacokinetics of diflunisal in patients

There are few pharmacokinetic data available on the disposition of diflunisal in patients; this study, therefore, looked at the oral absorption, distribution and elimination of this drug. Ten pharmacokinetic profiles obtained from 8 patients showed a maximum plasma diflunisal concentration of 62.0 +/- 26.5 mg/L after 2.76 +/- 1.87 hours, and an area under the plasma concentration-time curve (AUC) of 678.3 +/- 362.3 mg/L.h. Significant intra- and intersubject variability was observed in this group of patients. Analysis of biliary secretion of diflunisal in 4 patients suggested a biliary elimination and subsequent enterohepatic circulation ranging between 2.4 and 15.1%. The AUC for diflunisal in synovial fluid collected from 66 patients was about 70% of that for plasma. In none of 28 patients studied could any trace of diflunisal be observed in cerebrospinal fluid, even though the sensitivity of the assay allowed detection of concentrations as low as 0.01 mg/L.

Enantiomers in arthritic disorders

Drugs which have a center of asymmetry are often administered as an equal mixture of the two possible enantiomeric forms i.e. a racemate. However, there are frequently large pharmacodynamic and pharmacokinetic differences between enantiomers. Consequently, it is possible that while one enantiomer mediates the antiinflammatory or antirheumatic action, the other enantiomer, although adding little to the efficacy of the drug, may contribute to its adverse effects. Asymmetric drugs may also serve as sensitive pharmacological probes of the mechanisms underlying the action of drugs and the inflammatory processes which they modulate. These concepts are the focus for this review.

Clinical pharmacology and use of nonsteroidal anti-inflammatory drugs

This review informs clinicians about current clinical usage and pharmacokinetics of newer NSAIDs and aspirin. To understand the effects of these drugs, a review of prostaglandin synthesis and actions is provided.

[Efficacy, tolerability and therapeutic benefit of etodolac (Lodine 200) in rheumatologic practice]

Efficacy, safety and therapeutic benefit of etodolac (Lodine 200) in rheumatological practice. An open clinical trial performed by 974 rheumatologists enabled an evaluation of efficacy, safety and therapeutic benefit of etodolac (Lodine 200) on 4,947 patients with rheumatoid arthritis, ankylosing spondylitis and osteoarthritis of the lower limbs; the initial dosage was 600 mg/d (for 2 weeks), then 400 to 600 mg/d (for 2 to 4 weeks, according to the indication). Efficacy, assessed by classical items for NSAID's, was shown to be excellent to good by 61-77 p. 100 of patients, according to the indication. 7.7 p. 100 of patients only dropped out for lack of efficacy. 20.4 p. 100 of patients developed adverse effect(s) (AE), but the relationship between etodolac and AE was assessed "possible" or "probable" only for 9.6 p. 100 of patients; this figure should be compared to the 7.6 p. 100 of patients who dropped out for AE and to the 92 p. 100 of patients who assessed the global safety as "excellent or good". The therapeutic benefit was estimated very favorable: 75 p. 100 of patients felt better than at the beginning of the study, 64.5 p. 100 of patients wished to continue the treatment and the (mean) benefit-risk ratio assessed with a logarithm scale (-1 to +1), ranged from 0.45 to 0.6 according to the indication. Therefore, this trial confirmed the good efficacy and safety profile of etodolac on a large scale in normal clinical practice in France, following assessments during controlled trials. It also permitted to perfect new items of evaluation for NSAID's, in particular for therapeutic benefit.