A study of the relative hepatotoxicity in vitro of the non-steroidal anti-inflammatory drugs ibuprofen, flurbiprofen and butibufen

1. The cytotoxic and metabolic effects of ibuprofen, flurbiprofen and butibufen have been studied in primary cultured hepatocytes. Toxic effects were observed for all three drugs at 10 times the therapeutic plasma concentration. 2. None of the drugs affected cell survival after 48 h of continuous exposure at their therapeutic plasma concentration, although significant increases of LDH leakage were detected. 3. Ibuprofen and butibufen were the most active in impairing gluconeogenesis from lactate (88% and 76% inhibition respectively) after 6 h exposure at therapeutic plasma concentrations. 4. At 5 times therapeutic plasma concentrations, albumin synthesis was inhibited 40% (ibuprofen), 35% (flurbiprofen) and 100% (butibufen) after 6 h exposure and significant effects were also observed after 24 h exposure. 5. Urea synthesis was inhibited 11% by butibufen at its therapeutic plasma concentration but only at higher concentrations by the other drugs. 6. Butibufen was potentially the most hepatotoxic drug as it has the highest therapeutic plasma concentration and had the lowest margin between therapeutic and toxic concentrations.     

A study of the relative hepatotoxicity in vitro of the non-steroidal anti-inflammatory drugs ibuprofen,flurbiprofen and butibufen

1. The cytotoxic and metabolic effects of ibuprofen, flurbiprofen and butibufen have been studied in primary cultured hepatocytes. Toxic effects were observed for all three drugs at 10 times the therapeutic plasma concentration.

2. None of the drugs affected cell survival after 48 h of continuous exposure at their therapeutic plasma concentration, although significant increases of LDH leakage were detected.

3. Ibuprofen and butibufen were the most active in impairing gluconeogenesis from lactate (88% and 76% inhibition respectively) after 6h exposure at therapeutic plasma concentrations.

4. At 5 times therapeutic plasma concentrations, albumin synthesis was inhibited 40% (ibuprofen), 35% (flurbiprofen) and 100% (butibufen) after 6h exposure and significant effects were also observed after 24 h exposure.

5. Urea synthesis was inhibited 11% by butibufen at its therapeutic plasma concentration but only at higher concentrations by the other drugs.

6. Butibufen was potentially the most hepatotoxic drug as it has the highest therapeutic plasma concentration and had the lowest margin between therapeutic aiid toxic concentrations.     

Effects of Meloxicam,Compared with other NSAIDs,on Cartilage Proteoglycan Metabolism,Synovial Prostaglandin E2, and Production of Interleukins 1, 6 and 8, in Human and Porcine Explants in Organ Culture

Some non-steroidal anti-inflammatory drugs (NSAIDs) can accelerate joint damage in osteoarthritis by enhancing the production of pro-inflammatory cytokines or inhibiting cartilage proteoglycan synthesis. Meloxicam, a new NSAID, was compared with standard NSAIDs for its effect on proteoglycan synthesis and degradation in human and porcine cartilage explants, as well as the production of prostaglandin E₂ (PGE₂) and interleukins 1 and 6 by human synovial tissue explants in-vitro. Meloxicam at submicromolar concentrations inhibited synovial PGE₂ production but, up to therapeutic drug concentrations (≤ 4 μm ), did not affect synovial production of the pro-inflammatory cytokine IL-1. In contrast, hydrocortisone, 10 μm , a positive control, inhibited release of this cytokine, and indomethacin, 100 μm , increased its production. The lack of effects of meloxicam were evident irrespective of intrinsic IL-1 bioactivity of the synovia, production of IL-1 inhibitors or time of incubation. Production of the part antiinflammatory cytokine IL-6, was significantly increased by therapeutic concentrations of meloxicam, as well as by indomethacin. Another major pro-inflammatory cytokine, IL-8, was unaffected by therapeutic concentrations of meloxicam. Meloxicam, 0.1–4.0 μm , did not affect cartilage proteoglycan production whereas indomethacin, 100 μm , significantly reduced synthesis of these macromolecules. Thus meloxicam, at concentrations within the therapeutic range and at which pronounced inhibition of prostaglandin production is evident, affects neither cartilage proteoglycan production nor the production of those cytokines likely to be important in cartilage destruction.     

COMPARISON OF THEOPHYLLINE AND ENPROFYLLINE EFFECTS ON HUMAN NEUTROPHIL SUPEROXIDE PRODUCTION

1. We investigated effects of theophylline (widely used for the treatment of asthma) and enprofylline (a new xanthine derivative with negligible adenosine antagonism) on O2- production by human neutrophils with n-formyl-methionyl-leucyl-phenylalanine (FMLP) stimulation. 2. Therapeutic concentrations of theophylline (1-100 mumol/L) enhanced O2- production, maximally by 43.1 +/- 24.4% at 30 mumol/L; the same concentrations of enprofylline inhibited O2- production. 3. When each agent was administered after pre-incubation with adenosine deaminase (ADA) (0.1 U/mL), O2- production was inhibited in a concentration-dependent manner in comparison with that under administration of ADA alone. 4. These results suggest that the difference of effects in the two xanthine derivatives at therapeutic concentrations might be due to the presence or absence of adenosine antagonism.     

Inhibition of the A-23187-stimulated leukotriene and prostaglandin biosynthesis of rat basophil leukemia (RBL-1) cells by nonsteroidal anti-inflammatory drugs, antioxidants, and calcium channel blockers

Rat basophil leukemia cells (RBL-1), when grown in monolayer, synthesize from endogenous substrates the prostaglandins (PG) E2, F2 alpha, and I2 (measured as 6-keto-PGF1 alpha) and 6-sulfidopeptide-containing leukotrienes (SRS), as well as materials that react serologically with anti-12-hydroxyeicosatetraenoic acid (HETE). The non-steroidal anti-inflammatory drugs indomethacin and aspirin inhibited PGE2 synthesis by RBL-1 cells, which had been stimulated with the calcium ionophore A-23187, in a dose-dependent manner with an IC50 of 0.7 and 7.8 microM respectively. Indomethacin, when used at higher concentrations, also inhibited iSRS synthesis with an IC50 of 230 microM. Benoxaprofen, also a non-steroidal anti-inflammatory drug, inhibited both PGE2 and iSRS production in a dose-dependent manner, but inhibition of the iSRS biosynthesis was three times more effective than inhibition of PGE2 production. The anti-oxidants gossypol, butylated hydroxyanisole (BHA), nordihydroguariatic acid (NDGA), and 3-amino-1-[m-(trifluoromethyl)phenyl]-2-pyrazoline (BW755c) also inhibited iSRS synthesis more effectively than PGE2 biosynthesis. The IC50 values for inhibition of iSRS production were 0.2 microM (gossypol), 0.5 microM (BW755c), 0.6 microM (BHA), and 0.6 microM (NDGA) compared to 2.8 microM (gossypol), 2.0 microM (BW755c), 4.8 microM (BHA) and 2.6 microM (NDGA) for inhibition of PGE2 synthesis. Gossypol, BW755C, BHA, and NDGA, as well as benoxaprofen, inhibited i12-HETE-biosynthesis (IC50 for gossypol, 0.32 microM; and for benoxaprofen, 0.5 microM). Two calcium channel blockers, verapamil and nifedipine, inhibited PGE2, iSRS and i12-HETE synthesis in a dose-dependent manner. The calcium channel blockers inhibited iSRS synthesis ten times more effectively than PGE2 production.     

The effects of sulphasalazine and its metabolites on prostaglandin production by human mononuclear cells.

Although it has been proposed that sulphasalazine (SASP) and its metabolite 5-aminosalicylic acid (5-ASA) act therapeutically by inhibiting production of vasoactive and immunoregulatory prostaglandins (PGs), in previous in vitro studies these drugs have both inhibited and promoted PG production. This study demonstrates that SASP and 5-ASA promote or inhibit peripheral blood mononuclear cell PG production depending upon the PG measured, the concentration of the drug, and whether the cells were stimulated. Sulphapyridine, the other constituent of SASP, only inhibited production. At high concentrations of SASP and 5-ASA the viability of mononuclear cells was reduced. The enhancement of PG production and toxicity was greater with SASP than 5-ASA, while the PGs most affected by SASP were not those most affected by 5-ASA. Thus, in vitro SASP may possess properties other than those of 5-ASA and this may explain the different therapeutic properties of these two compounds.     

The effect of slow-acting anti-rheumatic drugs (SAARDs) and combinations of SAARDs on monokine production in vitro.

The mode of action of slow-acting anti-rheumatic drugs (SAARDs) is complex but may often include effects on cytokine (interleukin-1, IL-1, and tumour necrosis factor, TNF) production by monocytes/macrophages. Different SAARDs may have variable effects on cytokine production in vitro depending on the concentration of drug, the presence of other SAARDs and individual variation. The gold compounds gold sodium thiomalate (GST) and auranofin (AF) had a bimodal effect on cytokine production. High concentrations of GST (greater than 1 microgram/ml) weakly inhibited IL-1-beta secretion (without affecting IL-1-alpha or TNF secretion and without affecting cell-associated IL-1-alpha and IL-1-beta accumulation), and although AF (greater than 100 ng/ml) inhibited cytokine production it did so at concentrations near to the toxic range for the drug (greater than 200 ng/ml). GST and AF when used in combination inhibited cytokine production in a synergistic manner even at concentrations that would potentiate cytokine production if used individually. Hydroxychloroquine (HCQ) and sulfasalazine (SAP) were two other inhibitory SAARDs which acted synergistically in combination. Combination of HCQ and SAP with gold drugs gave variable results. D-penicillamine (D-pen) and methotrexate (MTX) were two SAARDs that generally did not affect cytokine production individually or in combination with other SAARDs. These results suggest that combination SAARD therapy may more effectively target excessive cytokine production, which is a hallmark of rheumatoid arthritis.     

Extremely prolonged elimination of cibenzoline at toxic plasma concentrations in patients with renal impairments

Three patients (age: 36, 68, and 80 years) treated with a standard oral dose of cibenzoline (300 mg/d) developed clinical symptoms being compatible with cibenzoline toxicity (e.g., prolonged QTc, wide QRS, arrhythmias, hypotension and hypoglycemia). Their plasma cibenzoline concentrations (i.e., 1944-2580 microg/L) were 5 to 10 times greater than the expected therapeutic levels. All patients had severe renal dysfunction (i.e., creatinine clearance: 10-16 mL/min) but had no severe liver damages. They received no drugs that might have inhibited hepatic drug metabolism. Intentional or accidental overdosing of the drug was ruled out in each patient. The elimination half-lives of cibenzoline monitored immediately after its withdrawal (i.e., 69, 116 and 198 hours) were 3-10 times longer than those reported in patients with end-stage renal failure of about 20 hours. In addition, two patients exhibited biphasic plasma drug decay curves. Our report indicates that not only reduced renal excretion but also non-linear kinetics of the drug via non-renal elimination at toxic concentrations may render renal failure patients more susceptible to cibenzoline toxicity.     

Inhibition of active oxygen generation by dipyridamole in human polymorphonuclear leukocytes.

The effect of dipyridamole on active oxygen generation by human polymorphonuclear leukocytes (PMN) was investigated. Dipyridamole inhibited the production of oxidative metabolites from human PMN stimulated by opsonized zymosan and formyl-methionyl-leucyl-phenylalanine dose and time dependently. To determine whether dipyridamole directly inhibits the production of oxygen metabolites by human PMN, human PMN were preincubated with dipyridamole washed prior to stimulation. Dipyridamole was found to directly inhibit human PMN from generated active oxygen metabolites at therapeutic concentrations. Dipyridamole may possibly be a potential scavenger of active oxygen metabolites since it inhibited active oxygen metabolite production from human PMN very rapidly. Dipyridamole was also found to directly affect the scavenging of active oxygen metabolites generated by opsonized zymosan-stimulated human PMN at therapeutic concentrations. This action of dipyridamole was also noted to be exerted against hydroxyl radicals and superoxide anions produced biochemically by an electron spin resonance spectrometer. It thus follows that dipyridamole may inhibit human PMN active oxygen metabolite generation and affect directly the scavenging of active oxygen metabolites at therapeutic concentrations.     

Thiamphenicol during the first trimester of human pregnancy: Placental transfer in vivo,placental uptake in vitro,and inhibition of mitochondrial function

Thiamphenicol (TAP) was administered as a single oral dose of 500 mg (8–9 mg/kg) to pregnant women about to undergo therapeutic abortions. The length of gestations varied from 7 to 12 weeks. The concentrations of TAP were determined by electron capture gas chromatography in maternal serum, placenta, amniotic fluid, and various embryonal/fetal tissues when abortion occurred 1.5 to 20 hr after drug administration. TAP was rapidly transferred across the placental membranes and was fairly evenly distributed in the tissues of the embryonal/fetal compartment. The placental concentrations of TAP were usually higher than the corresponding maternal serum levels (1.1 to 7-fold), suggesting some active role of the placenta in TAP uptake. This was confirmed by in vitro studies with immature and term placenta tissue. From a bathing medium containing 10 μg/ml (comparable to therapeutic blood levels) TAP was accumulated in the intracellular compartment to concentrations about 2.6 times those in the medium. This process was time and temperature dependent. Inspite of the low content of mitochondrial particles in human fetal liver the relatively few mitochondria present exhibited high protein synthesis in vitro which decreased with increasing gestational age. Mitochondrial protein synthesis was inhibited by TAP, and a 50% reduction of amino acid incorporation was observed at 10–15 μg TAP/ml. Such levels of the drug are required for successful chemotherapy. To ascertain such therapeutic drug levels, TAP is usually given at 3 g daily (divided, e.g., into three doses 1 g each). The data obtained for a single application of 0.5 g TAP suggest inhibition of mitochondrial protein synthesis during therapy. While the pharmacokinetic characteristics of TAP suggested that this compound might be well suited to treat intrauterine bacterial infections sensitive to TAP, the drug concentrations reached in human embryonal tissues in vivo are known to produce embryolethality in pregnant rats at comparable developmental stages. The findings reported here raise serious concerns about the suitability of TAP for repeated administration to pregnant women during the first trimester of gestation.     

Pharmacological activities of spirogermanium and other structurally related azaspiranes: effects on tumor cell and macrophage functions

Spirogermanium is a germanium containing azaspirane which has been shown to have activity in experimental models of cancer and immune dysfunction. A series of analogs of the parent compound were synthesized and evaluated in a number of in vitro and in vivo biological assays to define the structure-activity relationships of this class of compounds relative to their potential therapeutic activities. In a colony-forming assay using HT-29 human colon carcinoma cells various analogs in which carbon replaced germanium (e.g. carbon) retained the potent cytotoxic activity in vitro seen with spirogermanium. Increased cytotoxic potency within the group of carbon containing analogs was directly related to increase in the length of the alkyl group(s) attached to the carbon atom opposite the azaspirane ring structure. DNA and protein synthesis by HT-29 cells was inhibited by these compounds. However, inhibition occurred only at supralethal concentrations or after long exposure times with the drug. None of the azaspiranes demonstrated in vivo anti-tumor activity against P388 leukemia or ADJ-PC6 plasmacytoma. The effect of these compounds on macrophage cell function was evaluated in vitro by their ability to modulate superoxide (O2-) production by macrophages. Spirogermanium inhibited the production of O2- by activated macrophages with an IC50 of 5 microM. Although macrophage viability did not appear to be decreased at the respective IC50 concentrations, the rank order potency for the analogs in the O2- production assay was directly proportional to that measured for their cytotoxic potency in the HT-29 colony formation assay. The results demonstrate that, within this class of compounds, (1) potent biological activity does not require the presence of germanium in the structure; (2) in vitro cytotoxic activity does not appear to be a direct result of the inhibition of macromolecular synthesis, and (3) macrophage function can be modulated in vitro at non-cytotoxic concentrations. These results are discussed in context with the reported anti-tumor activity of spirogermanium and the potential anti-arthritic and immunomodulatory activity of this class of compounds.     

The effect of lithium, imipramine and chlorpromazine on the membrane bound enzyme phosphatidylethanolamine methyltransferase

The activity of phosphatidylethanolamine methyltransferase (PMT) in disrupted human erythrocytes and ghost cells was inhibited by lithium (Li+), imipramine and chlorpromazine. There was no inhibitory effect of the drugs in concentrations similar to the average therapeutic blood levels. Li+ exerted an inhibition on PMT activity in hemolysates at concentrations 8 times the average therapeutic level whereas chlorpromazine and imipramine showed an inhibitory effect on PMT in hemolysates at 10(3) fold their respective therapeutic serum level.     

Effects of antirheumatic drugs on leukotriene B4 and prostanoid synthesis in human polymorphonuclear leukocytes in vitro

The effects of D-penicillamine, sodium aurothiomalate, indomethacin, timegadine and tolfenamic acid on the lipoxygenase and cyclo-oxygenase pathways of arachidonic acid metabolism were studied in human polymorphonuclear leukocytes (PMNs) in vitro. In short-term incubations, D-penicillamine and aurothiomalate did not affect leukotriene B4 (LTB4), prostaglandin E2 (PGE2) or thromboxane B2 (TXB2) production. Each of the three non-steroidal anti-inflammatory drugs (NSAIDs) used were potent inhibitors of prostanoid synthesis. In higher concentrations they also reduced LTB4 production; timegadine and tolfenamic acid were effective in concentrations comparable to those measured in plasma during drug therapy, whereas indomethacin was needed in ten times higher concentrations. The different effects of NSAIDs on 5-lipoxygenase activity may be of importance in their therapeutic actions as well as in the appearance of some side-effects, e.g. gastric irritation and "aspirin-induced" asthma.     

INTERACTION OF THE NON-STEROIDAL ANTIINFLAMMATORY DRUG FLUFENAMIC ACID WITH GASTRIC ACID SECRETION AND H+/K+ -ATPase

1. The effects of the non-steroidal anti-inflammatory drug (NSAID) flufenamic acid on H+ production in isolated and enriched guinea-pig parietal cells and on H+/K(+)-ATPase activity in ion-tight inside-out membrane vesicles from pig gastric mucosa were studied. 2. At low concentrations (0.1 and 1.0 mumol/L), flufenamic acid increased the secretory response of parietal cells to dibutyryl cyclic AMP (dbcAMP). At higher concentrations (10 and 100 mumol/L) it progressively inhibited basal and dbcAMP-stimulated acid production. 3. Flufenamic acid (10 mumol/L) increased K+ (0.5-10.0 mmol/L) and K+ (0.5-1.0 mmol/L) plus gramicidin-stimulated ATPase activity in gastric membrane vesicles. The Km value for K+ (1.6 and 1.0 mmol/L in the absence and presence of gramicidin, respectively) was decreased to 0.8 and 0.5 mmol/L, respectively. At higher concentrations (greater than or equal to 50 mumol/L), flufenamic acid inhibited K+ plus gramicidin-stimulated ATPase activity (inhibited concentration at 50% [IC50] = 186 mumol/L) and reduced the proton concentration (IC50 = 50 mumol/L). 4. It is concluded that flufenamic acid-induced enhancement of dibutyryl cyclic AMP-stimulated H+ production in the parietal cell reflects the stimulation of H+/K(+)-ATPase. We suggest that activation of the enzyme involves increased affinity of K+ towards the K(+)-binding site of the enzyme and/or increased KCl permeability at the vesicle membrane. The inhibitory action of the drug on H+ production in parietal cells results from a detergent and/or protonophoric-like action at the apical parietal cell membrane, and from inhibition of H+/K(+)-ATPase activity.     

Tetrahydroaminoacridine blocks voltage-dependent ion channels in hippocampal neurons

Tetrahydroaminoacridine (THA) is a centrally active anticholinesterase that may produce functional improvement in patients with Alzheimer's disease. Because of its structural similarity to the potassium channel (A-current) blocking drug 4-aminopyridine (4-AP), it has been speculated that some of the therapeutic benefit of THA might result from inhibition of potassium currents. In the present study, THA produced a dose-dependent, reversible block of the A-current in cultured hippocampal neurons (IC50, 30 microM). However, at similar concentrations it also inhibited other voltage-dependent currents.     

Inhibition of rat neutrophil functional responses by azapropazone, an anti-gout drug

Azapropazone at concentrations of 0.1 to 1 mM inhibited by 30-70% rat neutrophil migration, aggregation, and degranulation in response to the synthetic chemotactic peptide fMet-Leu-Phe. Binding studies using fNle-Leu-[3H]Phe, a radiolabeled analog of fMet-Leu-Phe, showed that azapropazone did not inhibit these responses by interfering with fMet-Leu-Phe binding. Azapropazone also decreased both the apparent rate of production and maximal levels of superoxide anion (O2-) generated by cells stimulated with 100 ng/ml phorbol-12-myristate-13-acetate (PMA). The concentrations of azapropazone that inhibit these neutrophil responses in vitro approximate those previously found in vivo after administration of therapeutic doses of drug to rats or humans. Taken together, the data suggest that the efficacy of azapropazone in gouty arthritis may be partly due to its ability to inhibit key neutrophil functional responses in vivo.     

10606例次环孢素治疗药物监测结果分析

目的对我院2010年8月-2012年12月的10606例次环孢素治疗药物监测（TDM）数据进行统计分析．指导临床合理用药和减少药物不良反应。方法对我院1888例患者10606次符合入选条件的环孢素监测结果进行统计分析。，结果首次治疗药物监测结果在治疗窗内的仅占40．3％；治疗药物监测次数为1、2、3以及超过10次者分别占总人数的29．2％、13．7％、8．9％、14．8％；在监测次数为3次～5次的患者中，第1、2、3、4、5次治疗药物监测结果在治疗窗内的分别占总人数的38．2％、43．8％、45．9％、40．4％、33．9％。结论环孢素的药动学参数个体差异大．及时监测患者的环孢素血药浓度，可以指导临床合理用药。但目前监测次数偏少，达标情况不理想，即使监测多次也不能达到很好的效果，这可能与环孢索血药浓度受多种因素影响有关。     

5种治疗药物945例次血药浓度监测结果分析

目的对我院治疗药物浓度监测数据进行分析,为临床合理用药提供参考。方法采用系统回顾性方法,对我院2003年11月--2006年5月期间的血药浓度监测结果进行分析。结果5种药物进行945例次监测。达有效血药浓度的590例次,占总数62．4％;未达有效血药浓度的269例次。占总数28．5％;达中毒血药浓度的86例次,占总数9．1％。结论TDM在我院开展,多种原因导致药物未在治疗窗内。监测次数偏少。临床药师和医师应联合,充分利用TDM技术,建立一个长期有效的治疗方案,最大限度保证患者用药安全、有效、经济。