Synthesis, pharmacological screening and computational analysis of some 2-(1H-Indol-3-yl)-N'-[(un)substituted phenylmethylidene] acetohydrazides and 2-(1H-Indol-3-yl)-N'-[(un)substituted benzoyl/2-thienylcarbonyl]acetohydrazides

The undertaken research was initiated by transforming 2-(1H-Indol-3-yl)acetic acid (1) in catalytic amount of sulfuric acid and ethanol to ethyl 2-(1H-Indol-3-yl)acetate (2), which was then reacted with hydrazine monohydrate in methanol to form 2-(1H-Indol-3-yl)acetohydrazide (3). Further, The reaction scheme was designed into two pathways where, first pathway involved The reaction of 3 with substituted aromatic aldehydes (4a-o) in methanol with few drops of glacial acetic acid to generate 2-(1H-Indol-3-yl)-N'-[(un)substitutedphenylmethylidene]acetohydrazides (5a-o) and in second pathway 3 was reacted with acyl halides (6a-e) in basic aqueous medium (pH 9-10) to afford 2-(1H-Indol-3-yl)-N'-[(un)substitutedbenzoyl/2-thienylcarbonyl]acetohydrazides (7a-e). All The synthesized derivatives were characterized by IR, EI-MS and 1H-NMR spectral techniques and evaluated for their anti-bacterial potentials against Gram positive and Gram negative bacterial strains and it was found that compounds 7a-d exhibited antibacterial activities very close to standard Ciprofloxacin. The synthesized derivatives demonstrated moderate to weak anti-enzymatic potential against α-Glucosidase and Butyrylcholinesterase (BChE) where, compounds 7c and 5c exhibited comparatively better inhibition against these enzymes respectively. Compounds 7a, 7d and 7e showed excellent anti-enzymatic potentials against Lipoxygenase (LOX) and their IC₅₀ values were much lower than the reference standard Baicalein. Enzyme inhibitory activities were also supported by computational docking results. Compounds 5c, 7a, 7b and 7c also showed low values of % hemolytic activity as well, showing that these molecules were not toxic, indicating that these molecules can be utilized as potential therapeutic agents against inflammatory ailments.

Clinical pattern of zileuton-associated liver injury: results of a 12-month study in patients with chronic asthma

OBJECTIVE

Zileuton is a 5-lipoxygenase inhibitor approved by the US FDA in 1996 for the treatment of asthma in adults and children. During phase II/III clinical trials, zileuton was generally well tolerated, although elevations in ALT and AST levels were noted in some patients, and a single treated patient developed hepatocellular jaundice. To more fully characterise the hepatic effects of zileuton, and to establish appropriate monitoring guidelines, a 12-month open-label, safety surveillance study was conducted prior to FDA approval.

PATIENTS AND METHODS

In this study, 2458 patients with asthma received zileuton 600mg four times daily in addition to usual asthma care, and 489 patients were treated with usual asthma care only. All patients had their liver biochemistry checked monthly for the first 5 months, and at months 7, 10 and 12 thereafter.

RESULTS

A total of 109 patients (4.4%) receiving zileuton treatment had elevations in ALT levels to > or =3 x the upper limit of normal (ULN), including 31 patients (1.3%) who had levels elevated to > or =8 x ULN, compared with 5 of 480 patients in the usual care alone group (1.0%) who had levels elevated to > or =3 x ULN, of whom 1 (0.2%) had levels elevated to > or =8 x ULN. Elevations in ALT levels were generally not associated with increases in alkaline phosphatase and/or total bilirubin levels. Therefore, the hepatic injury was predominantly hepatocellular. The majority of elevations in ALT level to > or =3 x ULN (64.2%) in the zileuton-treated group occurred within the first 3 months of treatment. There was no correlation between the time of onset of ALT level elevation and the height of the peak ALT level observed. There was no overall difference in the occurrence of elevations in ALT level to > or =3 x ULN between men (4.5%) and women (4.7%), but more women than men experienced an ALT level > or =8 x ULN (1.8% vs 0.5%). Women aged > or =65 years appeared to be at higher risk of elevated ALT levels than those aged <65 years (a rate of 10.1% compared with 4.1%). Patients who experienced ALT levels of > or =3 x ULN but <5 x ULN were allowed to remain on treatment and 52.5% of these patients were able to continue zileuton therapy and experienced resolution of the elevation (a reduction in level to <2 x ULN). In each of the patients who discontinued treatment because of elevated ALT levels, the ALT level returned towards baseline, with a mean time to resolution (defined as a reduction in levels to <2 x ULN) of 4 weeks. No patient in this study developed clinically apparent jaundice or liver failure. Two patients (0.1%) experienced total bilirubin levels > or =1.5 x ULN in association with serum ALT levels exceeding 3 x ULN.

CONCLUSIONS

This study established that liver chemistry monitoring is most effective in detecting elevation of ALT levels during the first 3 months of zileuton therapy and that with appropriate monitoring the risk of irreversible liver injury appears to be low.

The safety and efficacy of zileuton controlled-release tablets as adjunctive therapy to usual care in the treatment of moderate persistent asthma: a 6-month randomized controlled study

This study was conducted to assess the safety and efficacy of zileuton controlled release [CR] 1,200 mg BID added to usual care (UC) in 926 patients with moderate asthma (619 patients randomized to zileuton CR and 307 to placebo). Sustained improvements in AM and PM peak expiratory flow (PEF) were observed in the zileuton CR group compared to placebo. The adverse event profile was similar in the two treatment groups. Eleven patients (1.8%) receiving zileuton CR and 2 (0.7%) receiving placebo experienced elevations of alanine aminotransferase (ALT) >or= 3X the upper limit of normal (ULN). These elevations typically occurred (81.8%) during the first 3 months of exposure and most resolved within 21 days after discontinuation.

The classical vs nonclassical NSAIDs: can the reduction in pain overcome the thrombotic risk?

The advent of cyclooxygenase-2 inhibitors has been both a blessing and a curse for pain management. An in-depth understanding of the biological molecules in the arachidonic acid metabolism may alleviate pain without risk.

Combined lipoxygenase/cyclo-oxygenase inhibition in the elderly: the example of licofelone

One of the categories of drugs most frequently used by the elderly, and probably the most commonly self-prescribed class of drug in this age group, is NSAIDs. However, NSAIDs are one of the primary causes of adverse drug reactions and are notorious for their gastric toxicity. They also inhibit renal function and reduce the efficacy of diuretics and ACE inhibitors, drugs that are commonly used by elderly patients. Recent studies have shown that cyclo-oxygenase (COX)-2 is important in renal physiology. This means that selective COX-2 inhibitors, while undoubtedly safer than NSAIDs in terms of gastric toxicity, are not devoid of renal toxicity (in addition to their now clearly established adverse effects on coronary heart disease risk). Both the gastric and renal toxicities induced by traditional NSAIDs and selective COX-2 inhibitors seem to be related to inhibition of prostaglandin, but not leukotriene, synthesis. Maintaining the correct balance between prostaglandins and leukotrienes is essential for continuing good health, but both classes of mediators also play an important role in the pathogenesis of several diseases.Recently, a new class of anti-inflammatory drugs, the lipoxygenase (LOX)/COX inhibitors, has been developed as a means of simultaneously inhibiting the synthesis of prostaglandins, thromboxanes and leukotrienes. Inhibition of leukotriene synthesis increases anti-inflammatory efficacy, particularly in rheumatic diseases, while reducing the risk of gastric damage. The LOX/COX inhibitor licofelone, which is currently in phase III trials, is the first of this new class and in the most advanced stage of development. Preliminary data with this drug seem promising, but further well designed clinical trials of this agent in the elderly will be necessary before a final evaluation is possible.

The Effects of a 5-Lipoxygenase Inhibitor on Acute Mountain Sickness and Urinary Leukotriene E 4 After Ascent to High Altitude

BACKGROUND

Elevated urine and blood leukotriene levels have been reported after ascent to high altitude in association with acute mountain sickness (AMS) and high-altitude pulmonary edema. Zileuton is an inhibitor of the enzyme 5-lipoxygenase that catalyzes conversion of arachidonic acid to leukotrienes. Study objectives and design: The objectives of this randomized, double-blind, placebo-controlled clinical trial were to determine whether zileuton (600 mg po qid) is effective prophylaxis for AMS, and to measure the effect of ascent to high altitude and zileuton on urinary leukotriene E(4) levels.

SETTING AND PARTICIPANTS

The study group consisted of volunteers from among climbers on the West Buttress of Mt. McKinley (Denali), Alaska. After baseline urine samples at sea level, subjects flew by airplane to 2,300 m, and then ascended to the 4,200-m camp in 5 to 10 days.

MEASUREMENTS AND RESULTS

Using an enzyme immunoassay, urinary leukotriene E(4) was found to decrease after ascent to high altitude in both the zileuton and placebo groups. Urinary leukotriene E(4) in the zileuton group (n = 9) decreased from 67 +/- 35 pg/mg creatinine at sea level to 33 +/- 22 pg/mg creatinine at high altitude (p = 0.003) [mean +/- SD]. Urinary leukotriene E(4) in the placebo group (n = 9) decreased from 97 +/- 82 pg/mg creatinine at sea level to 44 +/- 21 pg/mg creatinine at high altitude (p = 0.045). One subject in the zileuton group and three subjects in the placebo group met Lake Louise criteria for AMS after arriving at 4,200 m (p = 0.257).

CONCLUSIONS

Elevated leukotrienes are not associated with ascent to high altitude. In subjects with AMS, urinary leukotrienes were not elevated, suggesting that leukotrienes may not be a component of the pathophysiology of AMS. The low incidence of AMS and the small sample size in this study prevented determination of whether zileuton is effective prophylaxis for AMS.

Zileuton, a 5-lipoxygenase inhibitor, increases production of thromboxane A2 and platelet aggregation in patients with asthma

Leukotrienes, generated from arachidonic acid via the lipoxygenase pathway, play an important role in the pathophysiology of asthma. Therefore, leukotriene inhibitors, such as Zileuton, are used in the treatment of asthma. However, thromboxanes, generated from arachidonic acid via the cyclooxygenase pathway, play an important role in platelet aggregation and thrombosis. Therefore, we studied whether Zileuton, by shifting arachidonic acid to the cyclooxygenase pathway, enhances thromboxane production and, hence, platelet aggregation. Blood samples were collected from 10 asthmatic patients before and 2 weeks after standard Zileuton treatment. Spontaneous platelet aggregation was measured in platelet-rich plasma. Platelet-rich plasma was also used to determine thromboxane B(2), a stable metabolite of thromboxane A(2), as the indirect measure of thromboxane A(2) because thromboxane A(2) is too unstable for assay. Baseline thromboxane B(2) and platelet aggregation values in the 10 asthmatic patients were normal. Treatment with Zileuton for 2 weeks significantly increased thromboxane B(2) levels from baseline levels of 267 +/- 54 microg/l to 389 +/- 62 microg/l after 2 weeks of treatment (P < 0.0002). Spontaneous platelet aggregation also increased significantly from baseline values of 4.2 +/- 2.4% to 6.8 +/- 2.8% after 2 weeks of treatment (P < 0.0001). These results establish that Zileuton, an effective drug for asthma, adversely affects in vitro platelet function. The findings suggest that this drug, and perhaps related agents also, may pose a thrombotic risk; clinical attention will be needed to address this possibility.

Recurrent panniculitis in a man with asthma receiving treatment with leukotriene-modifying agents

Leukotriene-modifying drugs are novel agents introduced recently to treat asthma. Both 5-lipoxygenase inhibitors, such as zileuton, and leukotriene receptor antagonists, such as zafirlukast and montelukast, have proved effective in the treatment of asthma. To our knowledge, there have been no detailed reports regarding dermatologic manifestations of this class of drugs. This article describes an unusual case of erythema nodosum in a 46-year-old asthmatic man who received 2 different leukotriene modifiers.

5-Lipoxygenase inhibition: a new treatment strategy for Sjögren-Larsson syndrome

The Sjögren-Larsson syndrome (SLS) is a severe neurocutaneous disorder due to fatty aldehyde dehydrogenase (FALDH) deficiency. The recent discovery of the role of FALDH in the degradation of leukotriene B4 (LTB4) opened the way to the development of a new therapeutic strategy for SLS, i.e. 5-lipoxygenase inhibition. We treated one SLS patient with zileuton during five weeks. During the treatment period we found decreased values of LTB4 and omega-OH-LTB4. The severity of the pruritus diminished, and favorable changes in the child's behavior were observed. The height of the prominent "lipid peak" of cerebral white matter (that is characteristically found on proton magnetic resonance spectroscopy in SLS patients) decreased during treatment, and increased again when treatment was stopped. In conclusion, the beneficial effects of 5-lipoxygenase inhibition in SLS are very promising and encourage further research.

MK-591 acutely restores glomerular size selectivity and reduces proteinuria in human glomerulonephritis

BACKGROUND

Leukotrienes are 5-lipoxygenated (5-LO) metabolites of arachidonic acid that mediate some of the glomerular hemodynamic and structural changes in experimental and human glomerulonephritis.

METHODS

We conducted an open-label, pilot study of the short-term effects of leukotriene biosynthesis inhibition using an orally active 5-LO activating protein (FLAP) antagonist (MK-591) on glomerular function in patients with glomerulonephritis. Eleven adult patients (seven women, median age 38 years) with glomerulonephritis (5 lupus nephritis, 2 IgA nephropathy, 1 membranoproliferative, 1 membranous, 1 C1q-deficiency, and 1 idiopathic crescentic) and moderate renal insufficiency [glomerular filtration rate (GFR) 62 +/- 9 ml/min/1.73 m2] were given MK-591 at a dose of 100 mg orally twice a day for four days.

RESULTS

MK-591 reduced proteinuria (albumin and IgG excretion rates) from 3233 +/- 1074 to 1702 +/- 555 microg/min and from 196 +/- 78 to 148 +/- 55 microg/min for albumin and IgG, respectively (P < 0.05 for both). This was not accompanied by a reduction in systemic arterial pressure, GFR, or renal plasma flow. By analysis of the fractional clearance of polydisperse dextrans, baseline proteinuria resulted from a loss of size selectivity with enhanced passage of large (>52 A) dextrans as compared with healthy controls. Treatment with MK-591 caused a selective improvement in the enhanced passage of large (>58 A) dextrans without affecting the handling of smaller dextrans, indicating an improvement in glomerular size selectivity. MK-591 was well tolerated, and no adverse effects were observed.

CONCLUSIONS

Short-term therapy with MK-591 reduces proteinuria by restoring glomerular size selectivity and thus reduces transglomerular protein trafficking. These benefits may result from glomerular leukotriene biosynthesis inhibition, but other MK-591-specific actions cannot be excluded.

Double-blind trials of azelastine nasal spray monotherapy versus combination therapy with loratadine tablets and beclomethasone nasal spray in patients with seasonal allergic rhinitis. Rhinitis Study Groups

BACKGROUND

Azelastine hydrochloride is an H1-receptor antagonist with antiinflammatory properties that is available in the US as Astelin Nasal Spray for the treatment of seasonal allergic rhinitis. The symptoms of seasonal allergic rhinitis can initially be treated with monotherapy using either an antihistamine or an intranasal corticosteroid. Patients whose symptoms do not respond adequately are often prescribed a combination of both an antihistamine and an intranasal corticosteroid.

OBJECTIVE

Three multicenter, randomized, double-blind studies were conducted to determine whether patients with moderate-to-severe symptoms of seasonal allergic rhinitis who had responded inadequately to monotherapy with either an oral antihistamine or an intranasal corticosteroid, and who were candidates for combination therapy with both an oral antihistamine and an intranasal corticosteroid, could be effectively treated with azelastine nasal spray monotherapy.

METHODS

Following a 1- to 2-week washout period, patients were randomized to 7 days of double-blind treatment with either azelastine nasal spray (2 sprays per nostril bid, 1.1 mg/day) monotherapy or combination therapy with oral loratadine (Claritin, one 10-mg tablet/day) plus intranasal beclomethasone dipropionate monohydrate (Beconase AQ, 2 sprays per nostril bid, 336 microg/day). Efficacy was determined at the end of the study by both a physician assessment of the need for additional anti-rhinitis medication and a patient global evaluation of therapeutic effectiveness. The three studies were conducted at 71 investigational sites during the 1998 spring allergy season. Three separate studies were conducted to verify the reproducibility of the new study design.

RESULTS

In all three studies a total of 1,070 patients were randomized to double-blind treatment. There were no statistically significant differences in the percentage of patients treated with azelastine nasal spray versus patients treated with a combination of loratadine tablets and beclomethasone nasal spray who did not require additional anti-rhinitis medication (32% to 45% and 39% to 46%, respectively). The patient global evaluation indicated that 77% to 84% of the patients treated with azelastine nasal spray had symptomatic improvement and 85% to 90% of the patients treated with loratadine tablets and beclomethasone nasal spray had symptomatic improvement. The most commonly reported adverse experience with azelastine nasal spray was a transient aftertaste (8%), while the most commonly reported adverse experience with loratadine tablets and beclomethasone nasal spray in combination was headache (6%).

CONCLUSIONS

Based on the percentage of patients not requiring additional antirhinitis medication and the patient assessment of efficacy, azelastine nasal spray monotherapy was as effective as the combination of oral loratadine plus intranasal beclomethasone in treating moderate-to-severe symptoms of seasonal allergic rhinitis.

Bioavailability of carbamazepine from four different products and the occurrence of side effects

The relative bioavailability of four different carbamazepine products, showing large differences in in vitro dissolution profiles, was studied in healthy volunteers to correlate the occurrence of side effects with a measure of the rate of absorption in vivo for bioequivalence testing. Two of the three generic products investigated showed bioequivalence with respect to the extent of absorption with Tegretol. In vivo, the differences found in absorption rate were reflected in the occurrence of side effects, especially dizziness. As a measure for the rate of absorption, the partial AUC did not seem to be a good characteristic to test bioequivalence, as the variability is very high and dependent on the AUC taken. The Cmax/AUCpart seems more promising, especially the partial AUC directly after completion of the absorption process. The variability is low in the case of carbamazepine after a single dose. However, as long as no consensus on the use of other metrics and the objective (clinical or quality control aspects) of bioequivalence testing is reached, and no other pharmacokinetic characteristic is validated, Cmax should be the characteristic of choice for the rate of absorption in single-dose studies with carbamazepine products.

Effects of ABT-761, a novel 5-lipoxygenase inhibitor, on the pharmacokinetics of a single dose of ethinyl estradiol and levonorgestrel in healthy female volunteers

ABT-761 is a second-generation 5-lipoxygenase inhibitor in clinical development for the treatment of asthma. The effects of ABT-761 on the pharmacokinetics of an oral contraceptive were assessed in 21 female adult volunteers in a phase I, multiple-dose, open-label study. Subjects received a single dose of oral contraceptive (30 microg ethinyl estradiol and 0.15 mg of levonorgestrel) on each of days 1 and 29. Oral doses of 300 mg of ABT-761 were administered once daily beginning on day 15 continuing through day 29. Statistically significant decreases in maximum concentration (Cmax) and area under the concentration-time curve (AUC) of ethinyl estradiol were observed when oral contraceptive was administered concomitantly with ABT-761 compared with administration of oral contraceptive alone. The mean elimination rate constant of ethinyl estradiol increased by 30% (a mean decrease of 3.8 hours in half-life), and the mean apparent volume of distribution during the terminal phase (Vd(beta)/F) of ethinyl estradiol increased by 73% in the presence of ABT-761. Mean Cmax and AUC values for norgestrel decreased by 12% and 10%, respectively, when administered with ABT-761. Mean values for time to Cmax (tmax), terminal rate constant (beta), half-life (t1/2), and Vd(beta)/F of norgestrel were similar when oral contraceptive was administered alone or concomitantly with ABT-761. The mechanism responsible for the effect of ABT-761 on the clearance of ethinyl estradiol remains undefined. Because results of previous multiple-dose studies of ABT-761 do not provide any evidence of autoinduction, the effects of ABT-761 on the pharmacokinetics of ethinyl estradiol are more likely related to absorption of ethinyl estradiol.

Safety and clinical efficacy of zileuton in patients with chronic asthma

Zileuton, a leukotriene pathway inhibitor used to treat asthma, improves lung function, relieves symptoms, and is well tolerated. The purpose of this 12-month, parallel-group, open-label study was to assess the efficacy of zileuton and evaluate liver function in patients treated with this drug (approximately 2% of patients treated with zileuton in controlled trials had reversible liver enzyme elevations). A total of 2,947 patients at 233 centers in the United States were randomly assigned in a 5:1 ratio to treatment with zileuton plus usual asthma care or usual asthma care alone. Efficacy variables included asthma exacerbations; need for alternative treatment, steroid rescue, emergency care, and hospitalizations; forced expiratory volume in 1 second (FEV1); and asthma symptom scores. The safety evaluation included measurement of alanine aminotransferase levels. Patients treated with zileuton had significantly fewer corticosteroid rescues (P < 0.001), required less emergency care (P < 0.05), had fewer hospitalizations, and had greater increases in FEV1 (P = 0.048). They also had significantly greater improvements in asthma symptoms. Increases in alanine aminotransferase levels to three times or more the upper limit of normal occurred in 4.6% of patients treated with zileuton and 1.1% of those receiving usual care (P < 0.001); most increases occurred during the first 2 to 3 months. Alanine aminotransferase levels decreased to less than two times the upper limit of normal or to baseline levels during zileuton treatment or after drug cessation. Jaundice or chronic liver disease did not develop in any patient. Adding zileuton to the therapeutic regimens of patients with asthma is likely to improve asthma control and lower utilization of healthcare resources.

Dose-proportional pharmacokinetics of a new 5-lipoxygenase inhibitor, ABT-761, in healthy volunteers

ABT-761, a new potent 5-lipoxygenase inhibitor, is under development for the treatment of asthma. The pharmacokinetics and dose proportionality of ABT-761 after single doses (10-160 mg) of ABT-761 in 24 healthy male volunteers were investigated in a double-blind, placebo-controlled study. The compound was well tolerated, with no clinically significant effects on vital sign measurements, hematological parameters, clinical chemistry, urinalysis, or electrocardiogram. The plasma concentration-time profile of ABT-761 indicates that the drug declines in a monoexponential fashion after moderately slow absorption, with a tmax value of approximately 4 h. The terminal elimination t1/2 averaged 15 h, and was dose independent. ABT-761 mean values of Cmax and AUC were linearly related to drug dose. ABT-761 is well tolerated in healthy volunteers and the pharmacokinetics are linear in the single-dose range between 10 and 160 mg.

[New developments in asthma therapy: how do individual leukotriene antagonists work?]

Today it is generally acknowledged that bronchial asthma is a chronic inflammatory airway disease which is marked by recurrent bronchial obstructions and hyperreactivity of the airways. The best anti-inflammatory characteristics are shown by corticosteroids. However these can have considerable side-effects in long-term, systemic use. The search for alternative forms of therapy has for some time concentrated on the development and testing of leukotriene antagonists. These can limit the effect of leukotrienes via receptor antagonism or synthesis inhibition. The leukotrienes B4, C4, and D4 count as important key mediators in bronchial asthma. They are released by numerous inflammatory cells, have a bronchoconstricting effect and chemotactic characteristics, promote vessel permeability and increase mucous secretion. In addition, they probably increase bronchial hyperreactivity. Among biosynthesis restrictors, the 5-lipoxygenase restrictors have shown an anti-inflammatory effect in both experimental asthma models and in clinical use. In mild to moderate asthma, lung function improved and the use of a concomitant beta-agonist medication was reduced. While the older leukotriene receptor antagonists were rather disappointing, the newer substances display a significantly improved effect, are generally well tolerated and can also be given orally. In experimental asthma models, receptor antagonists, after antigen provocation, led to a marked reduction in bronchoconstriction and a decrease in the number of inflammatory cells (lymphocytes and eosinophils) in bronchial alveolar fluid. In clinical studies, this new class of drugs showed a reduction in clinical symptoms and an improvement in lung function in mild to moderate asthma. In addition, a bronchodilatatory effect was shown. The option of oral administration and good tolerance should improve compliance. The potential and long-term efficacy in severe asthma remains unclear. Further studies are required to elucidate the scope of their role and define their place in the treatment of asthma.

A randomized controlled trial comparing zileuton with theophylline in moderate asthma. The Zileuton Study Group

BACKGROUND

Zileuton, a leukotriene pathway inhibitor, was compared with slowly absorbed theophylline in a randomized, double-blind study of patients with chronic asthma. The primary efficacy measure was improvement in forced expiratory volume in 1 second (FEV1).

METHODS

Eligibility criteria included FEV1 of 40% to 80% of predicted, documented reversibility of airway disease, and age 18 to 60 years. Initially, the theophylline dosage was titrated to achieve trough concentrations of 8 to 15 micrograms/mL. After washout and 1-week placebo lead-in, patients were randomly assigned to 13 weeks of the appropriate theophylline dose or zileuton, 400 or 600 mg 4 times daily. The FEV1 was measured before the morning dose at 2-week intervals and serially after the dose on days 36 and 92. Patients kept daily diaries of asthma symptoms, beta-agonist usage, and peak expiratory flow rate; on days 36 and 92, they completed quality-of-life questionnaires.

RESULTS

Of 471 eligible patients at 38 centers, 377 were randomly assigned to the study; 313 completed the study. On first-dose administration, all groups showed 11% to 13% improvement in FEV1 within 30 minutes. Patients who received zileuton, 400 mg, had significantly greater improvement at several points than did theophylline-treated patients. The range of long-term maximum improvement in FEV1 in the groups was 30% to 34% (P = .40 for zileuton 600 mg; P = .90 for zileuton 400 mg vs theophylline). Initially, the theophylline group improved significantly more in symptom scores, beta-agonist usage, and peak expiratory flow rate, but at maximal effect there was no significant difference. All groups showed significant improvement in quality of life. No overall differences were observed between the zileuton dosage groups. Adverse events were comparable in all groups.

CONCLUSION

Zileuton appears as effective and safe as theophylline in patients with chronic asthma.

Randomized trial of zileuton in patients with moderate asthma: effect of reduced dosing frequency and amounts on pulmonary function and asthma symptoms. Zileuton Study Group

This 6-month, randomized, multicenter study was designed to determine whether patients who had been treated with the leukotriene pathway inhibitor zileuton 600 mg four times daily (QID) for 2 months could be maintained at the same level of pulmonary function, symptom control, and beta-agonist use with less frequent dosing--first 600 or 800 mg three times daily (TID) and then twice daily (BID). A total of 278 patients with chronic asthma, ages 16 to 70, participated at 25 US centers. All had a 1-second forced expiratory volume (FEV1) of 35%-75%, reversible airway disease, and a nonsmoking history of 1 year. An 8-week open-label period (zileuton 600 mg QID) was followed by a 16-week double-blind period, in which patients who responded to the QID treatment were randomized to receive zileuton 600 or 800 mg TID for 8 weeks and then rerandomized to receive zileuton 600 or 800 mg BID for another 8 weeks. Primary outcomes were FEV1 and asthma symptom scores; secondary outcomes were peak expiratory flow rate, beta-agonist use, and asthma exacerbations requiring steroid rescue. Patients who showed improvements in lung function when treated with zileuton 600 mg QID demonstrated minimal decreases in FEV1 and comparable peak expiratory flow rates, symptom control, beta-agonist use, and systemic corticosteroid rescue when being treated with lower doses and/or less frequent doses of zileuton. Patients who demonstrate improved asthma control with zileuton 600 mg QID may be able to reduce their daily dosage and/or frequency while still maintaining the same level of symptom control.

Acute and chronic effects of a 5-lipoxygenase inhibitor in asthma: a 6-month randomized multicenter trial. Zileuton Study Group

BACKGROUND

Leukotrienes produced by the 5-lipoxygenase pathway of arachidonic acid metabolism may mediate bronchoconstriction and inflammatory changes important in the pathophysiology of asthma. Leukotriene inhibition may be effective in asthma management.

OBJECTIVE

This clinical trial was performed to assess the long-term efficacy and safety of zileuton, an inhibitor of 5-lipoxygenase.

METHODS

In this multicenter, double-blind, parallel-group, placebo-controlled trial, 600 mg of zileuton, 400 mg of zileuton, or placebo was given orally, each four times daily for 6 months. Patients with mild to moderate asthma (n = 373), 18 to 62 years of age, being managed with regularly inhaled beta-agonist alone, were randomized to the zileuton or placebo groups (n = 122 to 126). Outcome measures included serial spirometry, daily peak expiratory flow rates, daytime and nocturnal symptoms, frequency of beta-agonist use, and number of asthma exacerbations treated with systemic corticosteroids.

RESULTS

An acute bronchodilatory effect was observed 2 to 5 hours after the initial dose of medication in both 400 mg zileuton and 600 mg zileuton groups compared to the placebo group. Both zileuton groups had significantly greater improvements in FEV1 than did the placebo group by day 8. On day 36, FEV1 improved 16% and 12% from baseline for patients treated with 600 mg zileuton and 400 mg zileuton, respectively, compared with an improvement of 6% for the placebo-treated group (p < 0.01, zileuton 600 mg vs placebo). Blood eosinophil levels were significantly reduced in both zileuton-treated groups compared with the placebo group. In the group receiving 600 mg zileuton, morning peak expiratory flow rate improved by 7% to 10%; daytime and nocturnal symptoms decreased by 37% and 31%, respectively; beta-agonist use decreased by 31%; and the proportion of patients requiring steroid rescue medication during the study was reduced by 62% (p < 0.05 for all comparisons of zileuton, 600 mg, vs placebo). Improvements were sustained over 6 months. Adverse events were similar in the three groups with no apparent, dose-related side effects.

CONCLUSION

Zileuton produces objective and subjective improvements in patients with mild to moderate asthma and is well tolerated.

Pharmacokinetics and pharmacodynamics of tepoxalin after single oral dose administration to healthy volunteers

This study was conducted to examine the pharmacokinetics and pharmacodynamics of tepoxalin in healthy volunteers, an antiinflammatory compound that inhibits cyclooxygenase and lipoxygenase. Tepoxalin was absorbed after oral administration of single doses from 35 to 300 mg, after which it was rapidly converted to an acidic metabolite, RWJ 20142, which inhibits cyclooxygenase but not lipoxygenase. The areas under the concentration-time curve (AUC) of tepoxalin and RWJ 20142 in plasma increased in a dose-dependent fashion. Administration of the lowest dose of tepoxalin completely inhibited whole blood cyclooxygenase for the entire period of observation. This inhibition correlated closely with that of secretion and aggregation induced by collagen of platelets obtained from these subjects. Similarly, administration of tepoxalin was associated with significant inhibition of lipoxygenase in whole blood. Lipoxygenase was inhibited a maximum of 60% in a time-dependent fashion, and the duration of inhibition was dose-dependent. These studies demonstrate that tepoxalin inhibits whole blood cyclooxygenase, lipoxygenase, and platelet function after oral administration in humans.

Effect of treatment with zileuton, a 5-lipoxygenase inhibitor, in patients with asthma. A randomized controlled trial. Zileuton Clinical Trial Group

OBJECTIVE

To study the effect of 3 months of treatment with zileuton, an inhibitor of the enzymatic pathway (5-lipoxygenase) leading to leukotriene formation, on disease control in patients with mild to moderate asthma.

DESIGN

Randomized, double-blind, parallel-group study in 401 patients. A 10-day placebo lead-in was followed by a double-blind treatment period of 13 weeks.

SETTING

Asthma study clinics in university hospitals and private practices.

PATIENTS OR OTHER PARTICIPANTS

Patients with mild to moderate asthma (forced expiratory volume in the first second [FEV1], 40% to 80% of predicted) whose only treatment was inhaled beta-agonists.

INTERVENTIONS

Treatment with 600 mg or 400 mg of zileuton or placebo (each taken four times daily.)

MAIN OUTCOME MEASURES

Frequency of asthma exacerbation requiring treatment with corticosteroids, use of inhaled beta-agonists, pulmonary function tests, asthma symptom assessment, and quality-of-life evaluation. Safety was evaluated by monitoring adverse events.

RESULTS

Only eight (6.1%) of 132 patients receiving 600 mg of zileuton four times a day required corticosteroid treatment for asthma vs 21 (15.6%) of 135 patients receiving placebo (P=.02), giving a relative risk of 2.6. At the time of expected peak drug concentration, the average FEV1 improved 15.7% in the 600-mg zileuton group vs 7.7% in the placebo group (P=.006). Quality-of-life assessments significantly improved in the 600-mg zileuton group and not in the placebo group (P=.007 for the overall score). Elevations in liver function tests (more than three times normal), all of which reversed with drug withdrawal, occurred in five patients (P=.03 vs placebo), three patients (P=.12 vs placebo), and no patients treated with 600 mg of zileuton, 400 mg of zileuton, or placebo, respectively.

CONCLUSIONS

Three months of 5-lipoxygenase inhibition produced a significant improvement in asthma control. These data indicate that 5-lipoxygenase products of arachidonic acid metabolism are mediators of inflammation with an important role in the biology of asthma.

Carbamazepine-induced hepatitis in a patient with cervical myelopathy

Carbamazepine is a drug commonly used in the treatment of neuropathic pain. It is an iminostilbene derivative that is extensively metabolized by the liver. We describe a 66-year-old man with dysesthetic pain from cervical myelopathy who developed cholestatic hepatitis, skin rash, and eosinophilia after carbamazepine was administered for 5 weeks (total dose of 18.9gm). Withdrawal of carbamazepine led to complete resolution of both clinical and biochemical abnormalities within 3 weeks. Clinicians should be alert to this rare complication because it can be confused clinically with biliary tract sepsis and viral hepatitis.

Topical R-85355, a potent and selective 5-lipoxygenase inhibitor, fails to improve psoriasis

Inhibitors of 5-lipoxygenase have been studied with respect to antipsoriatic efficacy. Of these compounds, R-68151 is of particular interest as it proved to inhibit 5-lipoxygenase without inhibiting 12-lipoxygenase, cyclooxygenase and thromboxane-A2 synthetase. R-68151 has been shown to have a mild-to-moderate therapeutic effect in psoriasis. In the present study a new 5-lipoxygenase, R-85355, was investigated with respect to its efficacy in psoriasis. R-85355 is 3 times more potent compared to R-68151 with respect to inhibition of in vitro A-23187-stimulated leukotriene-B4 production by polymorphonuclear leukocytes. In a left-right double-blind comparative study, the compound was studied at saturation with respect to its antipsoriatic efficacy in 11 patients with chronic stable plaque psoriasis. In addition, various markers for epidermal proliferation, keratinization and inflammation were assessed. In no single patient was a left-right difference observed in favour of R-85355 compared to placebo with respect to clinical severity scores or the cell-biological markers. The present study indicates that a selective and highly potent 5-lipoxygenase inhibitor was not effective in the topical treatment of chronic plaque psoriasis.

The pharmacokinetic and pharmacodynamic interactions between the 5-lipoxygenase inhibitor zileuton and the cyclo-oxygenase inhibitor naproxen in human volunteers

The potential pharmacokinetic and pharmacodynamic interactions between zileuton, a 5-lipoxygenase inhibitor, and naproxen, a nonsteroidal anti-inflammatory drug that acts as a cyclo-oxygenase inhibitor, have been investigated in 24 healthy volunteers. Coadministration of these 2 drugs had no effect upon the plasma concentration-time curves of either zileuton (800mg) or naproxen (500mg) when compared with each drug administered alone. Both naproxen plasma concentrations during the elimination phase and area under the plasma concentration-time curve values were statistically significantly raised upon coadministration with zileuton, when compared with naproxen alone. However, these differences in these 2 values were sufficiently small to be of no clinical significance. There is no evidence that the combination of zileuton and naproxen had an effect on leukotriene B4 levels that was different from the inhibitory effect of zileuton alone, or had an effect on serum thromboxane B2 levels that was different from the effect of naproxen alone. Moreover, inhibition of the 5-lipoxygenase pathway by zileuton did not appear to aggravate the gastrointestinal adverse events commonly associated with naproxen administration. It is concluded that zileuton and naproxen may be coadministered with minimal risk of a clinically significant interaction.

Gastrointestinal tolerance of [2,2-dimethyl-6-(4-chlorophenyl-7-phenyl- 2,3-dihydro-1H-pyrrolizine-5-yl]-acetic acid in the rat

The gastrointestinal tolerance of [2,2-dimethyl-6-(4-chlorophenyl)-7- phenyl-2,3-dihydro-1H-pyrrolizine-5-yl]-acetic acid (ML 3000, CAS 156897-06-2) has been tested in comparison with indometacin, after both single and multiple administrations for 5 and 11 days in an in vivo rat assay. A single oral administration of ML 3000 at doses of 10, 30 and 100 mg/kg produced no gastrointestinal damage. Repeated oral administration of ML 3000 at daily doses of 10, 30 and 100 mg/kg produced slight gastrointestinal damage, but the effect was minimal and was not found to be statistically significant. Indometacin produced highly statistically significant gastric and duodenal damage following one single administration of 10 mg/kg. Repeated oral administration, at 3 mg/kg each day, produced moderate and statistically significant gastric and slight duodenal damage on Day 5 of dosing. However, by Day 11 pronounced duodenal damage was observed which was shown to be statistically highly significant. These results indicate that ML 3000 is clearly better tolerated by the gastrointestinal tract than indometacin after single and multiple administration up to 11 days in rats.

Zileuton, a 5-lipoxygenase inhibitor in rheumatoid arthritis

The effects of zileuton, a new 5-lipoxygenase inhibitor, on leukotriene generation and clinical response in rheumatoid arthritis (RA) was studied in a 4-week randomized double blind placebo controlled study at 2 academic rheumatology centers. Zileuton decreased the mean (+/- SEM) ionophore induced synthesis of leukotriene B4 at Week 1 by 70% from 191.2 +/- 28.5 to 57.5 +/- 17.0 ng/ml. A parallel suppression of all major 5-lipoxygenase pathway products was observed. An improvement in clinical variables was observed in the zileuton and placebo treated population. No unique toxicity was identified in this study. Zileuton inhibited 5-lipoxygenase in RA with a suggestion of clinical response with limited toxicity.