Salicylate metabolism in twins. Evidence suggesting a genetic influence and induction of salicylurate formation.

To evaluate the contribution of genetic influences on the individual variation in plateau serum salicylate levels, salicylate metabolism was studied in seven pairs of identical and six pairs of fraternal twins.Under the conditions of this study, after a single i.v. dose (40 mg/kg) of sodium salicylate, the serum salicylate concentration versus time curve approximated a straight line on linear coordinates (appeared approximately zero order). The slopes of the decay curves ranged between 0.64 and 1.02. The intrapair variation for identical twin pairs was significantly less than for fraternal twin pairs (P = 0.044). Likewise pleateau serum salicylic acid concentrations (milligrams/deciliter) and total salicylic acid excretion rate after multiple doses demonstrated significantly less intrapair variation for identical twins than for fraternal twins (P = 0.043 and 0.006). Plateau salicylurate excretion (milligram/kilogram per hour) differences after multiple dosing had a P = 0.067. Michaelis-Menton constant for salicylurate formation and hours to 50% excretion after the i.v. dose were not different when comparing identical and nonidentical twins. Salicylurate formation rates were increased after 3 days of oral therapy, and this induction phenomenon may account for much of the apparent discrepancy between genetic influences on salicylurate formation rates observed after single and multiple dose salicylate administration. This study suggests that the plateau concentration of serum salicylate varies among individuals given the same weight-adjusted dose in part because of genetically determined variations in their metabolism of salicylate.

Human lymphocyte subpopulations. Effect of corticosteroids.

Normal subjects given 60 mg of prednisone orally at 8:00 a.m. developed a transient lymphopenia at 2:00 p.m. To define the populations of lymphocytes affected the number and type of lymphocytes in the peripheral blood were assayed. "Late" and "early" spontaneous sheep red blood cell rosettes were used as markers for thymus-derived (T) lymphocytes and one of its subpopulations, respectively. Receptors for aggregated gammaglobulin and complement identified bursal-equivalent or bone marrow-derived (B) lymphocytes and one of its subpopulations, respectively. 6 h after administration of 60 mg of prednisone, the blood samples showed a decrease in proportion of T cells from 69.2 +/- 2.1% to 55.9 +/- 2.8% (average +/- SE) and an increase in B-cell proportion from 21.3 +/- 2.0% to 44.8 +/- 4.1%. The changes of "early" rosettes and complement receptor lymphocytes also paralleled these. In all cases the absolute numbers of T cells and of B cells were decreased by prednisone. The density gradient distribution of the lymphocytes did not change after prednisone. These data indicate that both T and B lymphocytes are affected by the prednisone but that the T cell lymphopenia was more pronounced. The lymphopenia might reflect either sequestration in the marrow and/or transient arrest of recirculation.

ACR remission criteria and response criteria.

As additional DMARDs have been added to the armamentarium of rheumatologists over the last 60 years, the approach to the treatment of rheumatoid arthritis has changed. Many clinical studies now are geared toward evaluating the concept of eradicating inflammation as a method to seek the elusive goal of sustained remission in RA. One of the first descriptions of remission in 'RA' was by Short et al in 1948, when he documented the natural progression of the disease. Since that time, various criteria have been developed to define RA remission utilizing clinical, radiographic, and laboratory measures. The most stringent of criteria is the American College of Rheumatology Remission Criteria, developed in 1980, which consists of clinical symptoms and signs of inflammation including fatigue, joint pain, morning stiffness, joint tenderness, joint swelling, and erythrocyte sedimentation rate (ESR). Several reports have compared ACR remission criteria to Disease Activity Score (DAS) values to identify equivalent DAS remission values, and these have been extrapolated to modified versions of the DAS, the Simple Disease Activity Index (SDAI), and Clinical Disease Activity Index (CDAI). The ACR remission criteria and the response measures were not designed for use as the target or goal for the clinical management of individual RA patients in routine clinical practice. Nevertheless, rheumatologists yearn for the eradication of inflammation in all RA patients, and attaining remission may be achievable in the future.

Lack of effect of rheumatoid arthritis on clonixin metabolism.

The effect of rheumatoid arthritis on the metabolism of the analgesic, 2-(3-chloro-o-toluidino) nicotinic acid (clonixin), was evaluated in 12 patients with rheumatoid arthritis and in 12 matched healthy control subjects. Males, age-matched by decades, had no renal, gastrointestinal, or hepatic disease, and took no drugs during the study. Lower (p less than 0.02) serum albumins and higher globulins in the patients (albumin: 3.87 plus or minus 0.18; globulin: 3.14 plus or minus 0.28 gm/100 ml) than in the control subjects (albumin: 4.42 plus or minus 0.10; globulin: 2.36 plus or minus 0.08 gm/100 ml) were considered to be manifestations of rheumatoid arthritis. Fasting subjects were given single oral doses of 750 mg of clonixin. A spectrophotometric method was used to determine drug blood levels. Serum half-life was 1.45 plus or minus 0.12 hr in patients and 1.50 plus or minus 0.13 hr in control subjects (p greater than 0.5). Mean peak concentration developed at 1.7 hr and was 40.0 plus or minus 2.6 mug/ml for patients and 46.1 plus or minus 3.1 mug/ml for control subjects. Thus a single oral dose of clonixin results in comparable blood levels in male patients suffering from rheumatoid arthritis and in healthy control subjects.

Correlation of plateau serum salicylate level with rate of salicylate metabolism.

The range of plateau serum salicylate concentrations was 4.4 to 33 mg/100 ml in patients with rheumatoid arthritis after they were treated with 50 mg/kg of aspirin daily for 5 days. Individual plateau serum levels correlated better with urinary excretion rates of the metabolite, salicylurate (whose maximum production is capacity-limited), than with total urinary excretion of salicylates. These observations suggest that large intersubject variations in plateau serum salicylate levels are determined, at least in part, by similar differences in the maximum rates of capacity-limited metabolic reactions. For optimal therapeutic responses, individualization of aspirin dosage by following serum salicylate levels is recommended.

Individual variability in concentrations of urinary sulindac sulfide.

Among 70 patients with arthritis who were receiving satisfactory maintenance therapy with sulindac (300 to 400 mg daily), 64% had no detectable sulindac sulfide (active metabolite) in one to four random urine specimens. However, 36% had 1.0 to 7.8 (mean, 2.2 +/- 1.4) micrograms/ml sulindac sulfide in urine, similar to the therapeutically effective concentrations found in 24 concurrent plasma specimens (1.4 to 9.0 micrograms/ml). Ten patients had sulindac sulfide in only one or two of two to four urine specimens. Thus, 36% of the patients had pharmacodynamically significant concentrations of sulindac sulfide in urine, presumably capable of suppressing the cyclooxygenase pathway responsible for prostaglandin synthesis in the kidney and elsewhere. The findings suggest individual variability in the capacity for renal oxidation of sulindac sulfide to inactive metabolites, perhaps related to genetic or environmental factors or both. These findings may help to explain conflicting reports on the effects of sulindac on urinary prostaglandins and renal function.

Availability of salicylate from salsalate and aspirin.

Salicylate availability from salsalate (SSA) and aspirin (ASA) was examined in six rheumatoid arthritis patients in a multiple-dose double-blind crossover study. Doses contained equimolar amounts of salicylic acid. After initial ASA treatment to achieve therapeutic salicylate levels (150 to 300 micrograms/ml) the patients received equimolar doses of SSA or ASA. When steady state was achieved patients were hospitalized, and blood and urine specimens were obtained during three dosing intervals and during the washout period that followed. Thereafter, patients were placed on the alternate medication for at least a week and the in-hospital pattern was repeated. Despite insignificant differences in absorption of the formulations, as measured by urinary salicylate recovery, the plasma salicylic acid AUC was lower after SSA. Evidence indicates that this apparent lower availability of salicylate from SSA is due to incomplete hydrolysis to salicylic acid, the unhydrolyzed SSA being excreted mainly as glucuronide conjugates.

Tiflamizole elimination from plasma in rheumatoid arthritis.

Tiflamizole is a fluorinated diarylamidazole sulfone nonsteroidal anti-inflammatory drug not metabolized or excreted in urine. Its mean (+/- SD) elimination t 1/2 from plasma was 21.6 +/- 9 days (range 11.8 to 49.5 days) in 17 subjects with rheumatoid arthritis, and appeared to be first order in most of them. Plasma elimination t 1/2 was loosely related (r = -0.67) to stool frequency in eight subjects for whom stool frequency data were available. In one, cholestyramine decreased t 1/2 to 4.1 days. In two patients, synovial fluid total tiflamizole concentrations were approximately one-third of simultaneous plasma concentrations, but elimination t 1/2s from synovial fluid were of the same order as those from plasma. Even with infrequent dosing, the longer t 1/2 may help sustain the anti-inflammatory effects of this drug.

Relationship of serum naproxen concentration to efficacy in rheumatoid arthritis.

Twenty-four patients with rheumatoid arthritis were tested in a randomized, double-blind. Latin-square comparison of 250, 750 and 1500 mg of naproxen daily. Each received each dose for 2 wk and baseline disease activity was established during withdrawal of medication before and after the study. Nine standard measures of efficacy were tested at each evaluation. No order effect or change in baseline was found. Total and unbound naproxen concentrations were measured by high-pressure liquid chromatography and equilibrium dialysis, respectively. A linear dose-response relationship (P less than 0.05) was demonstrated between naproxen and joint count, patient's pain assessment, activities of daily living index, physician's global assessment, and grip strength. The relationship to patients' global assessment was of uncertain significance (P less than 0.07). A positive dose to serum level correlation (1, 2, and 12 hr after dose) was apparent (r greater than 0.78). When patients were defined as responders or nonresponders by a summed efficacy score, there was a serum concentration-response relationship; the percentage of responding patients increased with each serum level quartile: 25%, 31%, 59%, and 75%. Patients with a trough total serum naproxen concentration under 18 micrograms/ml did not respond, while 76% of patients with trough total serum concentrations above 50 micrograms/ml responded. No serum naproxen toxicity level relationship was established.

Tolmetin kinetics and synovial fluid prostaglandin E levels in rheumatoid arthritis.

Tolmetin kinetics were determined in the plasma and synovial fluid of five rheumatoid arthritis patients after they had ingested tolmetin (400 mg every 6 hr) for 7 days. Tolmetin was rapidly absorbed, with average peak levels in plasma and synovial fluid occurring at 45 min and 2 hr. The drug concentration in synovial fluid was higher than that in plasma for prolonged periods, while the rates of elimination from both plasma and synovial fluid were similar. The average half-lives of tolmetin in plasma and synovial fluid were 6.77 +/- 1.47 hr and 6.90 +/- 2.3 hr. Total prostaglandin E levels in synovial fluid of these patients were suppressed for at least 24 hr after the last dose of tolmetin, suggesting that PGE synthesis continues to be suppressed even by the very low concentrations of tolmetin remaining after 24 hr.

Antimalarial agents compared with or in combination with other disease-modifying antirheumatic drugs.

Available published comparisons of antimalarial drugs with other disease-modifying antirheumatic drugs (DMARDs) are reviewed, as well as reports of combinations of DMARDs, in the treatment of rheumatoid arthritis and juvenile rheumatoid arthritis. These reports suggest that antimalarial drug toxicity is less than that of parenteral gold, D-penicillamine, auranofin, or dapsone. Its efficacy appears to be equal to or slightly less than that of most comparison DMARDs. Combinations of DMARDs with antimalarials are probably used by a substantial proportion of rheumatologists, but the few prospective, double-blind studies with a balanced design show little or no advantage to combination DMARD therapy. Open, nonrandomized studies and preliminary reports suggest that combination therapy may be useful, usually when another DMARD is added to one or more DMARDs to which the patients did not have a satisfactory response. A few large, prospective, double-blind, randomized studies comparing hydroxychloroquine with several other DMARDs and placebo are needed to establish more confidence in the relative efficacy and utility of hydroxychloroquine. Although the rationale for combination DMARD therapy is attractive, additional preliminary studies of the various possible combinations and doses are needed before definitive trials of promising combinations can be justified.

Immunosuppressive and corticosteroid therapy of polyarteritis nodosa.

The clinical manifestations, treatment and survival of 64 patients with polyarteritis nodosa seen from 1955 to 1977 were evaluated. In general, the patients had multisystem involvement. No patient with cutaneous vasculitis alone was accepted into the study. The clinical diagnosis was confirmed by biopsy in 34 patients, by autopsy in 13 and by angiography in 10. The patients were treated at the discretion of the physicians responsible for their care. Eight of the 64 patients received only supportive therapy (group 1), 34 received corticosteroids alone (group 2), and 22 received both corticosteroids and an immunosuppressive agent (group 3). Five patients in group 2 and one patient in group 3 were excluded from survival studies because of insufficient length of therapy. Patients in the three treatment groups were very similar with respect to 18 clinical and laboratory variables. Median survival times for the three groups were three months, 63 months and 149 months, respectively; 5 year survival rates were 12 per cent, 53 per cent and 80 per cent (p less than 0.05). Despite difficulty in precisely defining polyarteritis nodosa, the data suggest a better prognosis for treated patients than has previously been appreciated, with improvement in outcome when an immunosuppressive agent is added to corticosteroid therapy.

The relationship arrhythmias and conduction disturbances to other manifestations of cardiopulmonary disease in progressive systemic sclerosis (PSS).

Disorders of rhythm and conduction are characteristic of the cardiac involvement in progressive systemic sclerosis (PSS), but their over-all frequency in PSS is not well established. Therefore, 46 ambulatory patients with PSS underwent several tests of cardiopulmonary function, including a 24-hour continuous electrocardiogram (Holter monitor). Conduction disturbances (sinus node dysfunction, first-degree heart block, pre-excitation), supraventricular arrhythmias (supraventricular tachycardia, atrial fibrillation, premature contractions of atrial or junctional origin) and ventricular arrhythmias (ventricular tachycardia, multifocal premature contractions) were observed on Holter monitoring in 26 subjects. Although these arrhythmias and conduction disorders were predictably observed in patients who complained of palpitations or syncope, or who had an electrocardiogram which showed first-degree heart block, ventricular bigeminy, left anterior superior hemiblock, prolonged p wave, right or left axis deviation, right or left ventricular hypertrophy, pathologic Q waves or low voltage, they were often found in patients who lacked other clinical evidences of heart disease. Arrhythmias and conduction disturbances were not significantly more frequent among patients with cardiomegaly or interstitial change on chest roentgenogram nor were they related to the presence or severity of abnormal lung function. This study suggests that Holter monitoring may be a valuable adjunct in evaluating heart disease in PSS.

Serum enzyme abnormalities in juvenile rheumatoid arthritis.

Elevated serum transaminases, particularly SGOT, as a result of acetylsalicylic acid (ASA) therapy have been reported in patients with juvenile rheumatoid arthritis (JRA). In order to evaluate the possibilities that these elevated transaminases may result from JRA itself or from concomitant muscle injury, we correlated liver function tests and a specific test for muscle damage, creatine phosphokinase (CPK), with ASA therapy in 37 patients. These JRA patients were evaluated serially; 20 took ASA continuously, 6 took it intermittently, and 11 were on no therapy. Thirty-five healthy children were also studied to establish normal control values for the serum enzyme tests. Mean SGOT and SGPT in the 11 untreated subjects were significantly (P less than.001) higher than normal controls while CPK and alkaline phosphatase (AP) were not elevated. Mean SGOT and SGPT were also significantly (P less than .001) elevated in 20 children receiving ASA continuously; CPK was normal and AP less (P less than .05) than normal. CPK was elevated in 13 patients. Elevation of enzymes was sporadic and there was no correlation with serum salicylate, sex, age, disease duration, type, or activity. We conclude that mild abnormalities of SGOT and SGPT in JRA patients are common, but that they occur sporadically and elevated values appear to be unrelated to ASA therapy.

Clinical pharmacokinetics of oral and injectable gold compounds.

The pharmacokinetics of oral gold (auranofin) in some respects resemble, and in other respects differ from, those of existing parenteral gold compounds such as gold sodium thiomalate (GST). This may in part relate to physicochemical differences as GST is a water-soluble polymeric compound in vitro whereas auranofin is lipid-soluble and characteristically monomeric. Furthermore, intramuscularly administered gold is greater than 95% bioavailable, whereas only 20 to 30% of an orally administered dose of auranofin is absorbed. Following a standard 50mg intramuscular injection of GST, serum gold concentrations rise sharply, peaking between 4 and 8 mg/L in approximately 2 hours and declining to an average of 3 mg/L by 7 days. With repeated injections of GST stable serum concentrations of gold (3 to 5 mg/L) are eventually achieved (usually within 5 to 8 weeks) although absolute concentrations may vary widely between patients. On the other hand, long term treatment with auranofin is associated with lower and more stable serum concentrations of gold (0.5 to 0.7 mg/L), on the standard dosing regimen of 6 mg daily. Both compounds are retained within the body for prolonged periods. However, the amount of gold retained with auranofin is significantly less compared with GST (less than 5% of a tracer dose of auranofin--about 20% of the absorbed dose--is retained by 100 days whereas the retention for a single labelled dose of GST over a similar interval is greater than 50%). Excretory patterns of GST and auranofin also differ. Most of an absorbed dose of GST (greater than 70%) is excreted by the kidneys whereas only 50% of an absorbed (15% of an administered) dose of auranofin is excreted in the urine. Both compounds are avidly bound by plasma proteins and auranofin shows a particularly strong association with circulating cellular elements. In human subjects, parenterally administered gold is widely distributed among bodily tissues, showing a predilection for tissues of the reticuloendothelial system as well as the kidney and adrenal cortex. Comparable studies in humans are not available for auranofin but animal studies have shown comparatively less affinity for the liver, kidney and spleen. Valuable insight has been gained in analysing the comparative pharmacokinetics of oral and injectable gold compounds. Unfortunately, attempts to correlate pharmacokinetic findings with clinical response or pharmacodynamic changes, as a whole, remain largely unsuccessful with these agents.

Protocol development for combination therapy with disease-modifying antirheumatic drugs.

To date, it has been exceptionally difficult to prove that any combination of disease-modifying antirheumatic drugs is more effective than its components used one at a time. However, only a few of many possible combinations have been evaluated in clinical trials. Careful attention to the details of patient selection, study design and duration, and choice of primary outcome measures is essential. A logical strategy for protocol development emphasizes the use of multiple small pilot studies to screen series of combinations and doses to identify a few that appear to show clinical benefit. The most promising combinations can then be evaluated in large, double-blind, randomized, pivotal studies with a higher probability of success.

Neuromuscular manifestations of L-tryptophan-associated eosinophilia-myalgia syndrome: a histomorphologic analysis of 14 patients.

The recent delineation of a clinical syndrome marked by eosinophilia, myalgia, and scleroderma-like skin changes associated with L-tryptophan use has necessitated the Centers for Disease Control to initiate a health alert. The likely association of L-tryptophan ingestion with a syndrome that mimics eosinophilic fasciitis (Shulman's syndrome) further identifies an environmental agent associated with an inflammatory sclerosing rheumatic disease process. In this report, we present the clinical, morphologic, and enzyme histochemical findings in muscle, skin, and fascia biopsies from 14 cases fulfilling the Center for Disease Control diagnostic criteria for L-tryptophan-associated eosinophilia-myalgia syndrome. The clinical syndrome reveals a high incidence of arthralgia, elbow contracture, and clinical neuropathy. The absence of significant change in creatine kinase or sedimentation rate allows for diagnostic separation from other inflammatory myopathies. Histoenzymatic features in muscle biopsies reveal a preferential epimysial-perimysial noneosinophilic infiltration characterized by acid phosphatase reactive histiocytosis, nonnecrotizing venulitis, perineural inflammation within dermis and perimysium, type II fiber atrophy with superimposed denervation features, and perifascicular alkaline phosphatase reactivity representing early neofibroplasia. The constellation of changes in skin, fascia, and muscle, with the defined clinical syndrome, allows for accurate differentiation from allied syndromes, including eosinophilic polymyositis, scleroderma, idiopathic polymyositis/dermatomyositis, polyarteritis nodosa, and toxic oil syndrome. Accurate differentiation from eosinophilic fasciitis still rests on a history of L-tryptophan ingestion.

Rheumatoid arthritis. Outcome measures.

Rheumatologists have been pioneers in the development and use of clinical measures for outcome assessment. The Lansbury Index (1958) and the Empire Rheumatism Gold Trial (1960) used sophisticated double-blind pseudo-placebo-controlled trial designs and standardized prespecified clinical outcome measures to establish the clinical usefulness of a drug whose benefit did not become evident until it was administered for several months. Since these studies, other studies have establish the clinical and statistical groundwork for rheumatoid arthritis outcome measures. In 1980, the Health Assessment Questionnaire and the Arthritis Impact Measurement Scales were added. Future development of paradigms for the decision process in the clinical management of individual rheumatoid arthritis patients will no doubt incorporate standard outcome measures to provide the data upon which management decisions can be based.

Clinical pharmacology of tolmetin: comparisons in rheumatoid arthritis patients and normal volunteers.

The pharmacokinetics of tolmetin sodium were studied in five patients with rheumatoid arthritis (RA) and five normal volunteers to determine whether data derived from normals could be applied to RA patients. In addition, prostaglandin E (PGE) levels in synovial fluid were compared with tolmetin levels in serum and synovial fluid. Both groups received 400 mg tolmetin every 6 hours for seven days. During a 24-hour washout period after the dose of tolmetin (400 mg) on day 8, blood and urine samples were obtained from all study participants, and synovial fluid samples from the RA patients only. The patients continued into a second 24-hour drug-free period, after which they received a single 400-mg dose of tolmetin. Blood and urine samples were again collected. No clinically or statistically significant differences in tolmetin kinetics between normal volunteers and RA patients were found. A comparison of multiple-dose and single-dose results in the patient group showed an 11 per cent increase in the tolmetin serum concentration after multiple dosing. Total PGE levels in synovial fluid remained significantly depressed in the patient group for 24 hours after the 400-mg test dose of tolmetin on day 8. These findings suggest that tolmetin serum kinetics may not be an appropriate indicator of the duration of biologic activity of tolmetin.

Metabolism of salsalate in normal subjects.

The metabolism of salsalate (I) was characterized in two normal volunteers. The drug was almost completely absorbed and was excreted primarily in the urine; only approximately 1% of the total dose was found in the stools. Although I is a salicylate derivative, which on hydrolysis yields two molecules of salicylic acid (II), approximately 7-10% of the dose was not hydrolyzed to salicylic acid and appeared in the urine either as unchanged drug or glucuronide conjugates. Thus, the incomplete availability of salicylate from salsalate that has been previously reported may not be due to incomplete absorption of the drug but to incomplete hydrolysis to salicylic acid.