Pharmacokinetic-pharmacodynamic drug interactions with nonsteroidal anti-inflammatory drugs

Review of the recent advances of pyrazole derivatives as selective COX-2 inhibitors for treating inflammation

Pyrazole heterocycle is regarded as an extremely significant agent for the therapy of inflammation. Celecoxib, lonazolac, deracoxib, and phenylbutazone are examples of commercially approved pyrazole drugs with COX-2 inhibitory potential for curing inflammation. There have been recently many reviews for the biological significance of pyrazole derivatives. This review talks about pyrazole derivatives with anti-inflammatory activity and also sheds the light on the recent updates on pyrazole research with an emphasis on some synthetic pathways utilized to construct this privileged scaffold and structure activity relationship that accounts for the anti-inflammatory activity in an attempt to pave the opportunity for medicinal chemists to develop novel anti-inflammatory agents with better COX-2 selectivity.

Exploring Headaches in Pediatric Behçet Disease: Prevalence, Clinical Impact, and Management

Behçet's Disease (BD), also recognized as Behçet Syndrome, manifests uniquely in pediatric populations as Pediatric Behçet's Disease (PBD), characterized by multisystemic inflammatory symptoms including recurrent oral and genital aphthae, and diverse ocular, vascular, and neurological involvements. This review elucidates the prevalence, burden, and management strategies of headaches in children with PBD, focusing on both primary headaches, such as migraine and tension-type headaches, and secondary headaches linked to systemic disease manifestations. It explores the pathophysiological underpinnings specific to PBD-related headaches and discusses the intricate relationship between systemic inflammatory processes and neurological symptoms. By examining the literature from 2004 to 2024, this study highlights the high frequency of headache in PBD patients, underscoring its diagnostic and clinical significance. We aim to provide a detailed understanding of headache management in PBD, emphasizing tailored therapeutic strategies that address the unique challenges faced by this patient population. This review also underscores the importance of comprehensive clinical evaluations to optimize outcomes and mitigate long-term sequelae, proposing that awareness and understanding of headache in PBD can significantly enhance both diagnosis and management.

A selective dual quenching sensor (EY/BG@CDs) for simultaneous monitoring of gentamicin and ketorolac levels in plasma: a highly efficient platform that caters to the needs of therapeutic drug monitoring

This research work introduces a novel sensor that utilizes two fluorophores to enable simultaneous monitoring of gentamicin sulphate (GNT) and ketorolac tromethamine (KET). The innovative sensor is composed of carbon dots (CDs) derived from black grapes (BG) and eosin Y (EY) dye. The interaction between the studied drugs and EY/BG@CDs sensor components allows for their simultaneous detection where GNT quenches the fluorescence of EY at 535 nm without affecting the fluorescence of CDs, while KET quenches the fluorescence of BG@CDs at 385 nm without impacting EY fluorescence. The BG@CDs probe was successfully characterized using various techniques such as absorption spectrophotometry, spectrofluorimetry, TEM imaging, infrared spectroscopic analysis, and XRD analysis. The suggested methodology was observed to be highly sensitive for the simultaneous determination of GNT and KET in their spiked rabbit plasma samples, with wide linear ranges and low limit of detection (LOD) values. The studied drugs were extracted using a highly selective extraction method involving protein precipitation followed by mixed mode solid phase extraction using an Oasis WCX cartridge. The simultaneous determination of GNT and KET is essential due to the potential interactions between the studied drugs. Therefore, this analysis can be used to evaluate the necessity of dose monitoring and the potential adverse effects of co-administration of these drugs.

Ibuprofen in the Management of Viral Infections: The Lesson of COVID-19 for Its Use in a Clinical Setting

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used for the management of fever, pain, and inflammation. However, they have always been considered to have a double-faced role, according to their capacity to manage inflammation but also their possible reduction of immune system response and diagnosis delay. This last point could favor a dramatic increase of viral infection diffusion, possibly leading to a more severe outcome. The advent of severe acute respiratory syndrome coronavirus 2 excluded the use of NSAIDs, particularly ibuprofen, and then indicated this drug as the better NSAID to manage infected outpatients and prevent complications. Several authors described the role of NSAIDs and ibuprofen in preventing cytokine storm and modulating the immune system. However, the development of both adverse drug reactions (i.e., gastrointestinal, renal, hepatic, and cardiovascular) and drug interaction recalled the necessity of prescribing the better NSAID for each patient. In this narrative review, we describe the role of NSAIDs, particularly of ibuprofen, in the management of viral symptoms, suggesting that the NSAID may be chosen considering the characteristics of the patient, the comorbidity, and the polytherapy.

Provider-directed analgesia for dental pain

INTRODUCTION

Extraction of impacted molar teeth is a common procedure performed by oral surgeons and general dentists, with postoperative pain being a significant adverse event post-surgery. If mismanaged, pain can lead to complications that impact oral and systemic health. The current scourge of the opioid epidemic has ushered in a new era of provider-directed analgesic (PDA) therapy in dentistry.

AREAS COVERED

This article provides an in-depth review on the major pharmacological and therapeutic properties of established and alternative analgesics used to manage dental pain.

EXPERT OPINION

Substantial evidence-based literature shows combination of a non-steroidal anti-inflammatory drug (NSAID; e.g. ibuprofen) and acetaminophen provides superior pain relief than single-agent or combination opioid regimens. However, there are clinical scenarios (e.g. severe pain) when short-course opioid prescription is appropriate in select patients, in which a 2-3-day treatment duration is typically sufficient. Alternative agents (e.g. caffeine, gabapentin, phytotherapies), typically in combination with established agents, can mitigate postoperative dental pain. Some evidence suggests preemptive therapies (e.g. corticosteroids, NSAIDs) reduce amounts of postsurgical analgesic consumption and might lessen opioid prescription burden. In summary, this comprehensive review provides an opportune update on the evolving landscape of pharmacotherapy for acute postsurgical dental pain, informing best practices for PDA in the dental setting.

The Pharmacological Treatment of Chronic Pain: From Guidelines to Daily Clinical Practice

In agreement with the International Association for the Study of Pain, chronic pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage. To date, there are several types of pain: nociceptive, neuropathic, and nociplastic. In the present narrative review, we evaluated the characteristics of the drugs used for each type of pain, according to guidelines, and their effects in people with comorbidity to reduce the development of severe adverse events.

Indomethacin-responsive headaches-A narrative review

BACKGROUND

Indomethacin is a nonsteroidal anti-inflammatory drug whose mechanism of action in certain types of headache disorders remains unknown. The so-called indomethacin-responsive headache disorders consist of a group of conditions with a very different presentation that have a particularly good response to indomethacin. The response is so distinct as to be used in the definition of two: hemicrania continua and paroxysmal hemicrania.

METHODS

This is a narrative literature review. PubMed and the Cochrane databases were used for the literature search.

RESULTS

We review the main pharmacokinetic and pharmacodynamics properties of indomethacin useful for daily practice. The proposed mechanisms of action of indomethacin in the responsive headache disorders, including its effect on cerebral blood flow and intracranial pressure, with special attention to nitrergic mechanisms, are covered. The current evidence for its use in primary headache disorders, such as some trigeminal autonomic cephalalgias, cough, hypnic, exertional or sexual headache, and migraine will be covered, as well as its indication for secondary headaches, such as those of posttraumatic origin.

CONCLUSION

Increasing understanding of the mechanism(s) of action of indomethacin will enhance our understanding of the complex pathophysiology that might be shared by indomethacin-sensitive headache disorders.

Management of patients receiving novel antithrombotic treatment in endodontic practice: Review and clinical recommendations

Cardiovascular diseases are a major component of non-communicable diseases and death, with thrombosis constituting the most common underlying pathosis of the three major cardiovascular disorders: ischaemic heart disease (acute coronary syndrome), stroke and venous thromboembolism (VTE). The introduction of direct oral anticoagulants (DOACs) in recent years has necessitated a more complex approach to periprocedural and perioperative anticoagulation management and the need for revised management strategies and protocols. Currently, patients taking classic oral anticoagulants are advised to stop taking the drugs and have their INR values checked 72 h prior to dental surgery (e.g., apical surgery, tooth extraction, and periodontal surgery) and checked again 24 h prior to the procedure to ensure it is within the therapeutic range. However, the current incorporation of these novel DOACs in routine medical practice requires changes in the way patients are managed preoperatively in dentistry, and specifically in endodontic surgery. The methodology applied in this review included searching for relevant articles in the PubMed database using keywords listed in the Entree Terms databases. Articles published on human blood clotting mechanism, antithrombotic drugs, as well as treatment guidelines and recommendations for dentistry were retrieved. In addition, textbooks and guidelines that may not have surfaced in the online search were searched manually. The aim of this paper was to review the mechanisms of action of classic and novel antithrombotic medications and their impact on endodontic treatment and the management of local haemostasis in endodontics.

Effects of Teicoplanin on the PT-INR Controlled by Warfarin in Infection Patients

Warfarin (WF) shows a number of interactions with other drugs, which alter its anticoagulant effects. The albumin binding interaction is one such pharmacokinetic mechanism of drug interaction with WF, which induces a rise in the free WF concentration and thus increases the risk of WF toxicity. Teicoplanin (TEIC) is an anti-methicillin-resistant Staphylococcus aureus drug, which also binds strongly to albumin in the plasma. Therefore, co-administration of TEIC may displace WF from the albumin binding site, and possibly result in a toxicity. The present study was performed to investigate the drug-drug interaction between WF and TEIC in comparison with controls treated with vancomycin (VCM), which has the same spectrum of activity as TEIC but a lower albumin binding ratio.The records of 49 patients treated with WF and TEIC or VCM at Fukuoka University Hospital between 2010 and 2015 were retrospectively reviewed. These 49 patients consisted of 18 treated with TEIC in combination with WF, while 31 received VCM in combination with WF. Prothrombin time-international normalized ratio (PT-INR) showed a significant increase of 80.9 (52.0-155.3) % after co-administration of TEIC with WF. In contrast, the rate of PT-INR elevation associated with VCM plus WF was 30.6 (4.5-44.1) %. These observations suggested that TEIC can cause a rise in free WF concentration by albumin binding interaction. Therefore, careful monitoring of PT-INR elevation is necessary in patients receiving WF plus TEIC.

[Drug interactions in pain therapy]

BACKGROUND

Pain is one of the most common reasons for consulting a physician. Chronic pain patients often suffer from a variety of comorbidities, such as depression and anxiety and they are therefore often simultaneously treated with more than one drug. The probability of drug interactions increases with every additional drug.

MATERIAL AND METHODS

A systematic internet and literature search up to February 2015 was carried out. Systematic lists were included. In addition, the drug prescription information sheets were used and an internet search via Pubmed and google.com was carried out for drugs alone and in combination in order to find substance-specific interactions.

RESULTS

A differentiation is made between pharmaceutical, pharmacodynamic and pharmacokinetic drug interactions. Pharmaceutical interactions are caused by chemical, physical or physicochemical incompatibility of drugs or adjuvants used. These can even occur outside the body and during concomitant administration via the same route. A pharmacodynamic interaction in pain management is for example the additive sedative effect of opioids and benzodiazepines when taken together. Pharmacokinetic interactions occur during the absorption, distribution, metabolism and in the elimination phases.

CONCLUSION

Many drug interactions can be avoided by careful and continuous evaluation of pharmacotherapy and if necessary its adaptation; however, a sound knowledge of the underlying pharmacological mechanisms and the properties of currently used analgesics is necessary.

Effect of ketoprofen and indomethacin on methotrexate pharmacokinetics in mice plasma and tumor tissues

Methotrexate (MTX) has been used in combination with nonsteroidal anti-inflammatory drugs in the treatment of inflammatory diseases as well as malignancies. Severe adverse effects with this combination may occur, usually resulting from inhibition of renal transporters. Solid Ehrlich carcinoma was experimentally induced by implantation of Ehrlich ascites Carcinoma cells subcutaneously into the thigh of mice, and after 30 days, mice were divided into three groups: Group I that served as control group received MTX (50 mg/kg, i.p.); Group II received ketoprofen (100 mg/kg, i.p.) and then after half an hour received MTX (50 mg/kg, i.p.); Group III received indomethacin (10 mg/kg, i.p.) and then after half an hour received MTX (50 mg/kg, i.p.). Plasma and tissue samples were collected at different time points and then MTX concentrations were determined by HPLC. The injection of ketoprofen or indomethacin before MTX injection resulted in significant increase in the AUC and CPmax of MTX (p < 0.05) and significant decrease in CL/F and Vd/F of MTX (p < 0.05) in mice plasma. The effects were more significant after injection of indomethacin than in case of ketoprofen. The study showed that administration of ketoprofen or indomethacin prior to MTX caused significant decrease in MTX elimination and significant increase in MTX extent of absorption which may lead to severe adverse effects if coadministered in human.

The Influence of NSAIDs on Coumarin Sensitivity in Patients with CYP2C9 Polymorphism After Total Hip Replacement Surgery

OBJECTIVE

To determine the influence of NSAIDs on the international normalized ratio (INR) in patients with cytochrome P450 (CYP)-2C9 enzyme variants starting acenocoumarol (an oral coumarin) therapy during the first 7 days after total hip replacement surgery.

METHODS

In this prospective study, an age-dependent protocol was used for the initiation of the acenocoumarol dose. Low-molecular-weight heparin was given for 5 days. The study included 100 patients undergoing total hip replacement surgery. After the inclusion of the last patient, polymerase chain reaction CYP2C9 mutation testing was performed for all patients. Drug-use evaluation of NSAIDs and other potential coumarin-drug interactions was also performed.

RESULTS

Eleven patients had an INR on 1 or more days >4.9. There were 52 patients who were using NSAIDs. Patients with a CYP2C9 mutation had a mean INR curve similar to patients without the mutation when NSAIDs were not coadministered. Within the group of patients heterozygous for a CYP2C9 mutation (n=30) only concomitant use of a NSAID resulted in an INR >4.9 (0% vs 38.9%, p<0.05).

CONCLUSION

In the group of patients with a CYP2C9 variant (*2 or *3 alleles), only concomitant use of a NSAID resulted in INRs >4.9. The cost effectiveness of CYP2C9 screening before elective surgery has yet to be determined.

Prevalence of the coprescription of clinically important interacting drug combinations involving oral anticancer agents in Singapore: a retrospective database study

BACKGROUND

There has been a recent increase in the availability and use of oral anticancer agents (OAAs). Drug-drug interactions (DDIs) involving OAAs pose a major concern in oncology practice due to these drugs' narrow therapeutic indices and potential for compromised efficacy and fatal adverse events.

OBJECTIVE

To assess the prevalence of the coprescription of potentially interacting drug combinations involving OAAs in Singapore.

METHODS

A retrospective review of physicians' electronic prescription records between the years 2007 and 2009 was performed in the largest cancer center in Singapore. An overall prevalence rate of potential DDIs and a prevalence rate for each individual DDI pair were calculated. Logistic regression was used to identify risk factors for potential DDIs.

RESULTS

Fifty-eight clinically significant DDIs were selected for evaluation from Drug Interaction Facts and Micromedex DrugDex. A total of 39,772 OAA prescriptions prescribed to 8837 patients were reviewed. Potential DDI coprescription was found in 5.4% of the patients on OAAs and in 4.7% of the OAA prescriptions. The drug pair prescribed to the largest number of patients was prednisolone and aspirin. About half (53.3%) of the observed DDIs were found on the same prescription. On multivariate analysis, older patients, males, and those taking prednisolone had a higher risk for potential DDIs.

CONCLUSION

Although limited by the data available, the analysis of prescription records found that ∼5% of patients taking OAAs in Singapore were exposed to ≥1 potentially interacting drug combination.

Safety issues in the development of treatments for osteoarthritis: recommendations of the Safety Considerations Working Group

OBJECTIVE

The symptomatic treatment of osteoarthritis (OA) remains to be improved, as many patients do not respond well to current palliative therapies and/or suffer unacceptable adverse events. Given the unmet need for innovative, effective and well-tolerated therapies, it is important to develop the means to estimate the ongoing safety profile of novel therapeutic agents over short- and longer term use.

DESIGN

Methods are presented to estimate the number of serious adverse events (SAEs) of interest considered as "acceptable" per 1000 patient-years exposure and to estimate the numbers of patient-years needed in a randomized controlled trial (RCT) to meet objectives. As exposure is increased, more evidence is accrued that the overall risk is within study limits. It is equally important that requirements for delineating the safety of promising new therapies not create barriers that would preclude their development. Therefore, ongoing surveillance of occurrence of SAEs of interest during clinical development is proposed, for example after every incremental 500 patient-years exposure are accrued.

RESULTS

This paper and others in this special issue focus on identification of safety signals for symptomatic treatments of OA. Much less information is available for agents aimed at slowing/preventing structural progression but it is expected that a higher risk profile might be considered acceptable in the context of more promising benefit.

CONCLUSION

This paper provides a proposal and supporting data for a comprehensive approach for assessing ongoing safety during clinical development of both palliative and disease-modifying therapies for OA.

Health care utilization among complementary and alternative medicine users in a large military cohort

Background

Complementary and Alternative Medicine use and how it impacts health care utilization in the United States Military is not well documented. Using data from the Millennium Cohort Study we describe the characteristics of CAM users in a large military population and document their health care needs over a 12-month period. The aim of this study was to determine if CAM users are requiring more physician-based medical services than users of conventional medicine.

Methods

Inpatient and outpatient medical services were documented over a 12-month period for 44,287 participants from the Millennium Cohort Study. Equal access to medical services was available to anyone needing medical care during this study period. The number and types of medical visits were compared between CAM and non-CAM users. Chi square test and multivariable logistic regression was applied for the analysis.

Results

Of the 44,287 participants, 39% reported using at least one CAM therapy, and 61% reported not using any CAM therapies. Those individuals reporting CAM use accounted for 45.1% of outpatient care and 44.8% of inpatient care. Individuals reporting one or more health conditions were 15% more likely to report CAM use than non-CAM users and 19% more likely to report CAM use if reporting one or more health symptoms compared to non-CAM users. The unadjusted odds ratio for hospitalizations in CAM users compared to non-CAM users was 1.29 (95% CI: 1.16-1.43). The mean number of days receiving outpatient care for CAM users was 7.0 days and 5.9 days for non-CAM users (p < 0.001).

Conclusions

Our study found those who report CAM use were requiring more physician-based medical services than users of conventional medicine. This appears to be primarily the result of an increase in the number of health conditions and symptoms reported by CAM users.

Inhibitory effect of selective cyclooxygenase-2 inhibitor lumiracoxib on human organic anion transporters hOAT1 and hOAT3

Nonsteroidal anti-inflammatory drugs (NSAIDs) delay renal excretion of antifolate methotrexate by inhibiting human organic anion transporters hOAT1 (SLC22A6) and hOAT3 (SLC22A8). In this study, we performed uptake experiments using Xenopus laevis oocytes to assess the inhibitory effect of selective cyclooxygenase-2 inhibitors on hOAT1 and hOAT3. The uptake of methotrexate into oocytes was increased by the injection of hOAT1 and hOAT3 cRNA, and transport was strongly inhibited by lumiracoxib. The apparent 50% inhibitory concentrations of lumiracoxib were estimated to be 3.3 µM and 1.9 µM for uptake of p-aminohippurate by hOAT1 and of estrone sulfate by hOAT3, respectively. Eadie-Hofstee plot analysis showed that lumiracoxib inhibited hOAT1 and hOAT3 in a competitive manner. For other cyclooxygenase-2 inhibitors celecoxib, etoricoxib, rofecoxib and valdecoxib, slight to moderate inhibition of hOAT3 only was observed. These findings show that lumiracoxib has inhibitory potential toward hOAT1 and hOAT3, comparable to that of nonselective NSAIDs.

Drug interaction between celecoxib and methotrexate in organic anion transporter 3-transfected renal cells and in rats in vivo

Methotrexate has a clinically important pharmacokinetic interaction with nonsteroidal anti-inflammatory drugs (NSAIDs) mainly through its competition for tubular secretion via the renal organic anion transporter 3 (OAT3). We have previously reported the usefulness of OAT3-transfected renal tubular cells for screening of the drugs which interfere with the pharmacokinetics of methotrexate. Celecoxib, a cyclooxygenase (COX) 2 inhibitor, has not been reported to interact with methotrexate, but the mechanisms are unclear why the interaction did not occur. The purpose of this study was to evaluate the effect of celecoxib on methotrexate tubular secretion using a renal cell line stably expressing human OAT3 (S2-hOAT3), and to evaluate the pharmacokinetic interaction of the two drugs in rats. [3H]methotrexate uptake into S2-hOAT3 cells was significantly inhibited by celecoxib in a concentration-dependent manner and the Ki value was 35.3 microM. However, methotrexate serum concentrations and urinary excretion of methotrexate over 24 h in rats were not affected by celecoxib (50, 200 mg/kg). Celecoxib serum concentrations were increased by the increase in celecoxib dosage and the maximum drug concentration (Cmax) was 20.6 microM (celecoxib 200 mg/kg), which did not reach the Ki value obtained in the in vitro study. These results indicated that celecoxib inhibited the secretion of methotrexate via hOAT3, which suggested that celecoxib was a substrate of hOAT3. However, co-administration of the two drugs at clinical dosage did not affect the pharmacokinetics of methotrexate, because the serum concentrations did not reach the Ki value. Although the accumulation study using S2-hOAT3 cells was useful to predict the interaction between the new drug and methotrexate in vivo, a comparison of the Ki value with the Cmax in clinical dosage was necessary to evaluate the degree of this interaction.

Risk factors of drug interaction between warfarin and nonsteroidal anti-inflammatory drugs in practical setting

Nonsteroidal anti-inflammatory drugs (NSAIDs) are known to interact with the oral anticoagulant warfarin and can cause a serious bleeding complication. In this study, we evaluated the risk factors for international normalized ratio (INR) increase, which is a surrogate marker of bleeding, after addition of an NSAID in a total of 98 patients who used warfarin. Patient age, sex, body mass index, maintenance warfarin dose, baseline INR, coadministered medications, underlying diseases, and liver and kidney functions were evaluated for possible risk factors with INR increase > or =15.0% as the primary end-point. Of the 98 patients, 39 (39.8%) showed an INR elevation of > or =15.0% after adding a NSAID to warfarin therapy. Multivariate analysis showed that high maintenance dose (>40 mg/week) of warfarin (P=0.001), the presence of coadministered medications (P=0.024), the use of meloxicam (P=0.025) and low baseline INR value (P=0.03) were the risk factors for INR increase in respect to NSAID-warfarin interaction. In conclusion, special caution is required when an NSAID is administered to warfarin users if patients are taking warfarin >40 mg/week and other medications interacting with warfarin.

The elderly patient and postoperative pain treatment

The management of postoperative pain in elderly patients can be a difficult task. Older patients have co-existing diseases and concurrent medications, diminished functional status and physiological reserve and age-related pharmacodynamic and pharmacokinetic changes. Pain assessment presents numerous problems arising from differences in reporting cognitive impairment and difficulties in measurement. The elderly are also at higher risk of adverse consequences from surgery and unrelieved or undertreated pain. Selection of analgesic therapy needs to balance the potential efficacy with the incidence of interactions, complications or side effects in the post-operative period. Drug titration in the post-anaesthesia care unit should be encouraged together with analgesia on request in the wards. Multimodal analgesia, using acetaminophen, non-steroidal anti-inflammatory drugs or other non opioid drugs, is the best way to decrease opioid consumption and thus opioid-related adverse events. Sophisticated analgesic methods like PCA, regional analgesia and PCEA are not contraindicated in the elderly but pain relief and side effects should be monitored.

Immunomodulatory effect of nonsteroidal anti-inflammatory drugs (NSAIDs) at the clinically available doses

Non-steroidal anti-inflammatory drugs (NSAIDs) with cyclooxygenase (COX) inhibitory activity are commonly used in various inflammatory diseases. In this study, to examine the immunomodulatory effects of well known NSAIDs at clinically available doses, macrophage- and T cell-mediated immune responses such as tumor necrosis factor (TNF)-alpha release and nitric oxide (NO) production, cell-cell adhesion, phagocytic uptake and lymphocyte proliferation were investigated. NSAIDs tested significantly enhanced TNF-alpha release from lipopolysaccharide (LPS)-activated RAW264.7 cells at certain concentrations (fenoprofen, indomethacin, piroxicam, aceclofenac, diclofenac and sulindac) or in a dose-dependent manner (aspirin and phenylbutazone). Of NSAIDs, phenylbutazone and aspirin most potently attenuated NO production, although sulindac was the only compound with cytoprotective activity against LPS-induced cytotoxicity. Most NSAIDs used displayed weak or no modulatory effects on phagocytic uptake and CD29- or CD43-mediated cell-cell adhesion. Interestingly, however, phenylbutazone itself triggered cell-cell clustering under normal culture conditions and enhanced the phagocytic activity. Aspirin and phenylbutazone also dose-dependently attenuated CD4+ T cell proliferation stimulated by concanavalin A (Con A) and CD8+ CTLL-2 cell proliferation induced by interleukin (IL)-2. Sulindac only blocked CTLL-2 cell proliferation. These results suggest that NSAIDs may differentially exert immunomodulatory effects on activated macrophages and lymphocytes, and some of the effects may enforce NSAID's therapeutic effect against inflammatory symptoms.

Rofecoxib: an update on physicochemical, pharmaceutical, pharmacodynamic and pharmacokinetic aspects

Rofecoxib (MK-966) is a new generation non-steroidal anti-inflammatory agent (NSAID) that exhibits promising anti-inflammatory, analgesic and antipyretic activity. It selectively inhibits cyclooxygenase (COX)-2 isoenzyme in a dose-dependent manner in man. No significant inhibition of COX-1 is observed with rofecoxib up to doses of 1000 mg. The pharmacokinetics of rofecoxib has been found to be complex and variable. Mean oral bioavailability after single dose of rofecoxib (12.5, 25 or 50 mg) is 93% with t(max) varying widely between 2 and 9 h. It is highly plasma-protein bound and is metabolized primarily by cytosolic reductases to inactive metabolites. Rofecoxib is eliminated predominantly by hepatic metabolism with a terminal half-life of approximately 17 h during steady state. Various experimental models and clinical studies have demonstrated rofecoxib to be superior, or at least equivalent, in anti-inflammatory, analgesic and antipyretic efficacy to comparator nonselective NSAIDs in osteoarthritis, rheumatoid arthritis and other pain models. Emerging evidence suggests that rofecoxib may also find potential use as supportive therapy in various pathophysiologic conditions like Alzheimer's disease, and in various malignant tumours and polyps, where COX-2 is overly expressed. Rofecoxib is generally well-tolerated. Analysis of data pooled from several trials suggests that rofecoxib is associated with fewer incidences of clinically symptomatic gastrointestinal ulcers and ulcer complications vis-à-vis conventional NSAIDs. However, this gastropreserving effect may be negated by concurrent use of low-dose aspirin for cardiovascular risk reduction. Rofecoxib tends to show similar tolerability for renal and cardiothrombotic events as compared with nonnaproxen nonselective NSAIDs. No clinically significant drug interaction has been reported for rofecoxib except with diuretics, where it reverses their salt-wasting effect and thus can be clinically exploited in electrolyte-wasting disorders. There is only modest information about the physicochemical and pharmaceutical aspects of rofecoxib. Being poorly water soluble, its drug delivery has been improved using varied formulation approaches. Although it is stable in solid state, rofecoxib is photosensitive and base-sensitive in solution form with its degradation mechanistics elucidated. Analytical determinations of rofecoxib and its metabolites in biological fluids employing HPLC with varied types of detectors have been reported. Isolated studies have also been published on the chromatographic and spectrophotometric assay of rofecoxib and its degradants in bulk samples and pharmaceutical dosage forms. The current article provides an updated overview on the physicochemical, pharmaceutical, pharmacokinetic and pharmacodynamic vistas of rofecoxib.

Impaired tubular excretory function as a late renal side effect of chemotherapy in children

PURPOSE

Renal drug excretion is variously influenced by nephrotoxic drugs. This study was designed to evaluate renal function as a late renal side effects in children receiving combination chemotherapy for malignancy.

PATIENTS AND METHODS

Follow-up studies of 30 newly diagnosed patients were performed a median of 12 months after completion of chemotherapy. The glomerular filtration rate (GFR) was measured using sodium thiosulfate. The following were also assessed: urinary high-molecular-weight fraction (urinary albumin/urinary creatinine ratio); para-aminohippurate (PAH) clearance; urinary low-molecular-weight fraction (urinary beta2-microglobulin/urinary creatinine ratio); and routine serum and urinary parameters.

RESULTS

Serum and urinary electrolytes were normal in most patients. GFR was low in four patients (13%). Urinary high-molecular-weight fraction was elevated in two patients. Urinary low-molecular-weight fraction was elevated in one patient. PAH clearance was below the referenced normal value in 73% of the patients.

CONCLUSIONS

This report demonstrates decreased PAH clearance as a late renal side effect of chemotherapy and suggests disturbed function of the organic anion transport system. The unexpected high serum concentration of drugs excreted through the organic anion transport system may induce severe side effects. Elucidation of the mechanism and clinical relevance of decreased PAH clearance is warranted.

Herbal medication: potential for adverse interactions with analgesic drugs

The use of herbal supplements in the US has increased dramatically in recent years. These products are not regulated by the Food and Drug Administration (FDA) with the same scrutiny as conventional drugs. Patients who use herbal supplements often do so in conjunction with conventional drugs. This article is a review of potential adverse interactions between some of the commonly used herbal supplements and analgesic drugs. Non-steroidal anti-inflammatory drugs (NSAIDs), particularly aspirin, have the potential to interact with herbal supplements that are known to possess antiplatelet activity (ginkgo, garlic, ginger, bilberry, dong quai, feverfew, ginseng, turmeric, meadowsweet and willow), with those containing coumarin (chamomile, motherworth, horse chestnut, fenugreek and red clover) and with tamarind, enhancing the risk of bleeding. Acetaminophen may also interact with ginkgo and possibly with at least some of the above herbs to increase the risk of bleeding. Further, the incidences of hepatotoxicity and nephrotoxicity may be augmented by acetaminophen when concomitantly used with the potentially hepatotoxic herbs Echinacea and kava, and with herbs containing salicylate (willow, meadowsweet), respectively. The concomitant use of opioid analgesics with the sedative herbal supplements, valerian, kava and chamomile, may lead to increased central nervous system (CNS) depression. The analgesic effect of opioids may also be inhibited by ginseng. It is suggested that health-care professionals should be more aware of the potential adverse interactions between herbal supplements and analgesic drugs, and take appropriate precautionary measures to avoid their possible occurrences. However, as most of the interaction information available is based on individual case reports, animal studies and in vitro data, further research is needed to confirm and assess the clinical significance of these potential interactions.

Clinical implications of drug interactions with coxibs

Nonsteroidal antiinflammatory drugs (NSAIDs) often are prescribed to patients who are taking concomitant drugs. Cyclooxygenase (COX)-2 inhibitors (coxibs) rofecoxib and celecoxib are highly selective inhibitors of COX-2, differentiating them from nonselective NSAIDs, which substantially inhibit both COX-1 and COX-2. Like nonselective NSAIDs, coxibs are hepatically metabolized: rofecoxib primarily by reduction by cytosolic enzymes and celecoxib by the cytochrome P450 (CYP) enzyme system. Because rofecoxib is not significantly metabolized by CYP, it has fewer confirmed or potential drug interactions than celecoxib. However, potent inducers of CYP, such as rifampin, may decrease rofecoxib concentrations because of induction of general hepatic metabolic activity. Celecoxib is metabolized by CYP2C9 and may be increased or decreased by CYP2C9 modifiers. It also inhibits CYP2D6 and may affect concentrations of CYP2D6 substrates. Similar to NSAIDs, many pharmacodynamic interactions involving coxibs are related to inhibition of production of renal prostaglandins. However, coxibs have no antiplatelet activity and may be preferred to NSAIDs in patients receiving antithrombotic therapy. Nonetheless, when a potential for an interaction exists, standard monitoring is recommended when starting or discontinuing a coxib. Due to lack of data to support these interactions, which are primarily theoretical, additional studies are necessary to establish the drug interaction profiles of coxibs.

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

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

Ex vivo assay to determine the cyclooxygenase selectivity of non-steroidal anti-inflammatory drugs

1. In this study we describe experiments to establish ex vivo the selectivity of non-steroidal anti-inflammatory drugs (NSAIDs) given in vivo. 2. Anaesthetised (Inactin, 120 mg kg(-1)) male Wistar rats (220-250 g) received an i.v. dose of one of the following compounds (dose mg kg(-1)): aspirin (20), diclofenac (3), L-745,337 (30), nimesulide (15), salicylate (20), sulindac (10). Blood samples were taken before and up to 6 h after dosing and the plasma obtained from it was tested for its ability to inhibit prostanoid formation in IL-1beta-treated A549 cells (COX-2 system) and human washed platelets (COX-1 system). For control the same compounds were also added directly to the assay systems. 3. All drugs, except sodium salicylate, inhibited COX-1 and COX-2 when added directly to the test systems. Plasma from aspirin-treated rats was without effect on either COX-1 or COX-2, consistent with the rapid in vivo metabolism to salicylate. Conversely, plasma from sulindac-treated rats inhibited COX-1 and COX-2 with potencies according with in vivo metabolism to sulindac sulphide. Diclofenac was COX-1/2 non-selective when tested in vitro, but a slightly preferential inhibitor of COX-2 when tested ex vivo. Nimesulide was confirmed as preferential inhibitor of COX-2 both in vitro and ex vivo. L-745,337 was a selective COX-2 inhibitor when tested in vitro or ex vivo. 4. In conclusion, our experiments show clearly (a) NSAIDs inactivation, (b) activation of prodrugs, and (c) NSAIDs selectivity. Our assay provides useful information about the selectivity of NSAIDs that could be extended by the analysis of plasma samples taken from humans similarly treated with test drugs.

Adverse drug interactions in dental practice: interactions associated with analgesics, Part III in a series

BACKGROUND

Numerous reports of drug interactions exist, yet not all are valid in or pertinent to dentistry. This article provides an overview of drug interactions with analgesics and identifies those that are clinically relevant.

METHODS

The author reviewed reports of drug interactions involving nonsteroidal anti-inflammatory drugs, or NSAIDs (including aspirin), acetaminophen and opioids to determine the interactions' validity and clinical relevance. Consistent with the practice followed in other articles in this series, the author determined the significance of the proposed interaction by gauging its reported severity and the quality of the documentation.

RESULTS AND CONCLUSIONS

NSAIDs should not be taken by patients taking high-dose methotrexate, anticoagulants or alcohol. They should be avoided in elderly or renally impaired patients taking digoxin, and avoided over the long term in those taking other NSAIDs. It is possible that NSAIDs should not be given to patients taking lithium, but future studies should be conducted to confirm this. Use of NSAIDs likely is appropriate in the short term with patients taking antihypertensives, unless they have severe congestive heart disease. Aspirin should not be given to patients taking oral hypoglycemics, valproic acid or carbonic anhydrase inhibitors. Acetaminophen may be given in the short term to any patient with a healthy liver, but it should not be given to a patient who has stopped drinking alcohol after chronic intake. Opioids should not be combined with alcohol, and meperidine must be avoided in the patient who has taken monoamine oxidase inhibitors in the previous 14 days.

CLINICAL IMPLICATIONS

Drug interactions with analgesics are often reported, but only a small number have clinical relevance in dentistry. Awareness of the significance of these interactions will allow dentists to prescribe analgesics optimally and minimize the potential for adverse reactions.

Lack of interaction between tramadol and coumarins

The objective of this study was to investigate whether the central analgesic tramadol influences the effects of the coumarin anticoagulant phenprocoumon during multiple-dose administration. Nineteen patients receiving long-term anticoagulant therapy who had been in a stable hypothrombinemic state for at least 3 months completed a double-blind, placebo-controlled, crossover study. Tramadol was administered in the usual therapeutic dose of 50 mg three times daily. The average daily phenprocoumon dose was identical for individual patients in both treatment periods. The equivalence ratio (tramadol/placebo) of the international normalized ratio (INR) values was 0.99 (90% confidence interval 0.89-1.10), thus fulfilling predetermined bioequivalence criteria (0.70-1.43). Therefore, tramadol does not affect INR in patients being treated with phenprocoumon. These data suggest a lack of interaction between tramadol and coumarin anticoagulants.

Clinical pharmacokinetics of nimesulide

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

[Benefit-risk and monitoring modalities of different techniques and methods of postoperative analgesia]

This review aimed to determine the benefits-risks ratio of postoperative analgesia. The various agents usually used for intravenous postoperative analgesia (paracetamol, NSAID's, opioids), and the techniques for postoperative analgesia (PCA, epidural, perinervous block) are analysed. The rules proposed for the monitoring of postoperative analgesia are considered.

A hydrogel based on a polyaspartamide: characterization and evaluation of in-vivo biocompatibility and drug release in the rat

This paper deals with the characterization of a new microparticulate hydrogel obtained by gamma irradiation of alpha, beta-poly[N-(2-hydroxyethyl)-DL-aspartamide] (PHEA). When enzymatic digestion of PHEA hydrogel was evaluated using various concentrations of pepsin and alpha-chymotrypsin no degradation occurred within 24 h. In-vivo studies showed that this new material is biocompatible after oral administration to rats. PHEA hydrogel was also studied as a system for delivery of diflunisal, an anti-inflammatory drug. In-vitro release studies in simulated gastrointestinal juice (pH 1 or 6.8) showed that most of the drug was released at pH 6.8. In-vivo studies indicated that diflunisal-loaded PHEA microparticles significantly improved the gastric tolerance and oral bioavailability of the drug in comparison with free diflunisal. These results suggest the potential application of PHEA hydrogel as a new delivery system for the oral administration of anti-inflammatory drugs.

Clinical pharmacokinetics of naproxen

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