Interaction between digoxin and indomethacin or ibuprofen

[Current challenges for therapy of comorbid patients: a new look at celecoxib. A review]

The use of non-steroidal anti-inflammatory drugs (NSAIDs) for a wide range of diseases is increasing, in part due to an increasing elderly population. Elderly patients are more vulnerable to adverse drug reactions, including side effects and adverse effects of drug-drug interactions, often occurring in this category of patients due to multimorbidity and polypharmacy. One of the most popular NSAIDs in the world is celecoxib. It is a selective cyclooxygenase (COX)-2 inhibitor with 375 times more COX-2 inhibitory activity than COX-1. As a result, celecoxib has a better gastrointestinal tract safety profile than non-selective NSAIDs. Gastrointestinal tolerance is an essential factor that physicians should consider when selecting NSAIDs for elderly patients. Celecoxib can be used in a wide range of diseases of the musculoskeletal system and rheumatological diseases, for the treatment of acute pain in women with primary dysmenorrhea, etc. It is also increasingly used as part of a multimodal perioperative analgesia regimen. There is strong evidence that COX-2 is actively involved in the pathogenesis of ischemic brain damage, as well as in the development and progression of neurodegenerative diseases, such as Alzheimer's disease. NSAIDs are first-line therapy in the treatment of acute migraine attacks. Celecoxib is well tolerated in patients with risk factors for NSAID-associated nephropathy. It does not decrease the glomerular filtration rate in elderly patients and patients with chronic renal failure. Many meta-analyses and epidemiological studies have not confirmed the increased risk of cardiovascular events reported in previous clinical studies and have not shown an increased risk of cardiovascular events with celecoxib, irrespective of dose. COX-2 activation is one of the key factors contributing to obesity-related inflammation. Specific inhibition of COX-2 by celecoxib increases insulin sensitivity in overweight or obese patients. Combination therapies may be a promising new area of treatment for obesity and diabetes.

Significance of Organic Anion Transporter 2 and Organic Cation Transporter 2 in Creatinine Clearance: Mechanistic Evaluation Using Freshly Prepared Human Primary Renal Proximal Tubule Cells

Creatinine, a clinical marker for kidney function, is predominantly cleared by glomerular filtration, with active tubular secretion contributing to about 30% of its renal clearance. Recent studies suggested the potential involvement of organic anion transporter (OAT)2, in addition to the previously known organic cation transporter (OCT)2-mediated basolateral uptake, in creatinine active secretion. Here we characterized the transport mechanisms of creatinine using transfected human embryonic kidney (HEK)293 cells and freshly prepared human primary renal proximal tubule epithelial cells (hPTCs). Creatinine showed transport by OAT2 in transfected HEK293 cells. In addition, both creatinine and metformin showed transport by OCT2 and multidrug and toxin extrusion pump (MATE)1 and MATE2K, while penciclovir was selective for OAT2. Time-dependent cell accumulation was observed for creatinine and metformin in hPTCs. Their accumulation was increased by pyrimethamine but inhibited by decynium-22, likely due to differential inhibition of OCT2 versus MATEs. Additionally, indomethacin (an OAT2 inhibitor) reduced penciclovir uptake (∼75%) in hPTCs illustrating functional OAT2 activity. However, no modulation of creatinine and metformin cell accumulation was apparent with indomethacin. Creatinine transport characteristics in the presence of inhibitors approached those of metformin, an OCT2/MATE substrate, but were distinct from those of penciclovir, an OAT2-selective substrate. Moreover, indomethacin showed no significant effect on the basolateral-to-apical transport and net secretion of creatinine across hPTC monolayers. Collectively, the functional studies suggest OCT2 as the primary basolateral uptake mechanism and that OAT2 has a minimal role, in creatinine renal secretion. Our results highlight the utility of hPTCs to enable the functional assessment of renal transport mechanisms. SIGNIFICANCE STATEMENT: Our results obtained with primary hPTCs indicate that OCT2/MATE (vs. OAT2) play a major role in the active renal secretion of creatinine. Quantitative pharmacokinetic models should therefore focus on OCT2/MATE when describing serum creatinine and creatinine clearance modulation by inhibitor drugs and genotype- or disease-related activity changes. The present study highlights the utility of freshly isolated hPTCs to support solute carrier phenotyping to enable the functional assessment of renal transport mechanisms.

Nonsteroidal Anti-inflammatory Drugs Utilization Patterns and Risk of Adverse Events due to Drug-Drug Interactions among Elderly Patients: A Study from Jordan

Background

Worldwide, the prescribing pattern of the Nonsteroidal Anti-inflammatory Drugs (NSAIDs) has increased. They are considered highly effective medications in controlling various conditions including inflammatory diseases. They are associated with various adverse effects including gastrointestinal bleeding and ulcer and renal toxicity though. These adverse effects are generally potentiated when NSAIDs are co-prescribed with other drugs that share similar adverse effects and toxicities. Developing severe side effects from NSAIDs is more prone among elderly patients. Hence, it is crucial to evaluate prescribing pattern of these agents to prevent/decrease the number of unwanted side effects caused by NSAIDs.

Aim

The aim of this study is to assess the prescribing pattern of NSAIDs among elderly and the co-prescribing of NSAIDs and different interacting drugs, which could lead to more incidences of NSAIDs-induced toxicities among Jordanian elderly patients.

Settings and Methodology

A multicenter retrospective study was performed during a three months period in Jordan. The study involves a total number of (n = 5916) elderly patient’s records obtained from Four governmental hospitals in Jordan.

Results

A total number of (n = 20450) drugs were prescribed and dispensed for patient. NSAIDs drugs prescribing percentage was 10.3% of total medications number. Aspirin was the most commonly prescribed NSAIDs among patients (70.4%), followed by Diclofenac sodium in all dosage forms (25.1%) and oral Ibuprofen (3.1%. In addition, Aspirin was the highest NSAIDs co-prescribed with ACEI (e.g., Enalapril), ARBs (e.g. Candesartan and Losartan), Diuretics (Furosemide, Indapamide, Hydrochlorothiazide, Amiloride, and Spironolactone), Warfarin and antiplatelets (Clopidogreal and Ticagrelor) followed by Diclofenac and other NSAIDs.

Conclusion

NSAIDs prescribing rate among elderly patients was high. Additionally the co-prescribing of NSAIDs especially Aspirin with other agents, which contributes to NSAIDs nephrotoxicity and gastrointestinal toxicity, were high. Strict measurements and action plans should be taken by prescribers to optimize the medical treatment in elderly through maximizing the benefits and decreasing the unwanted side effects.

Predicting the serum digoxin concentrations of infants in the neonatal intensive care unit through an artificial neural network

BACKGROUND

Given its narrow therapeutic range, digoxin's pharmacokinetic parameters in infants are difficult to predict due to variation in birth weight and gestational age, especially for critically ill newborns. There is limited evidence to support the safety and dosage requirements of digoxin, let alone to predict its concentrations in infants. This study aimed to compare the concentrations of digoxin predicted by traditional regression modeling and artificial neural network (ANN) modeling for newborn infants given digoxin for clinically significant patent ductus arteriosus (PDA).

METHODS

A retrospective chart review was conducted to obtain data on digoxin use for clinically significant PDA in a neonatal intensive care unit. Newborn infants who were given digoxin and had digoxin concentration(s) within the acceptable range were identified as subjects in the training model and validation datasets, accordingly. Their demographics, disease, and medication information, which were potentially associated with heart failure, were used for model training and analysis of digoxin concentration prediction. The models were generated using backward standard multivariable linear regressions (MLRs) and a standard backpropagation algorithm of ANN, respectively. The common goodness-of-fit estimates, receiver operating characteristic curves, and classification of sensitivity and specificity of the toxic concentrations in the validation dataset obtained from MLR or ANN models were compared to identify the final better predictive model.

RESULTS

Given the weakness of correlations between actual observed digoxin concentrations and pre-specified variables in newborn infants, the performance of all ANN models was better than that of MLR models for digoxin concentration prediction. In particular, the nine-parameter ANN model has better forecasting accuracy and differentiation ability for toxic concentrations.

CONCLUSION

The nine-parameter ANN model is the best alternative than the other models to predict serum digoxin concentrations whenever therapeutic drug monitoring is not available. Further cross-validations using diverse samples from different hospitals for newborn infants are needed.

A Comprehensive Review of Non-Steroidal Anti-Inflammatory Drug Use in The Elderly

NSAIDs, non-steroidal anti-inflammatory drugs, are one of the most commonly prescribed pain medications. It is a highly effective drug class for pain and inflammation; however, NSAIDs are known for multiple adverse effects, including gastrointestinal bleeding, cardiovascular side effects, and NSAID induced nephrotoxicity. As our society ages, it is crucial to have comprehensive knowledge of this class of medication in the elderly population. Therefore, we reviewed the pharmacodynamics and pharmacokinetics, current guidelines for NSAIDs use, adverse effect profile, and drug interaction of NSAIDs and commonly used medications in the elderly.

Medication overuse and chronic migraine: a critical review according to clinical pharmacology

INTRODUCTION

Chronic migraine is often complicated by medication-overuse headache (MOH), a headache due to excessive intake of acute medications. Chronic migraine and MOH are serious and disabling disorders. Since chronic migraine derives from the progression of originally episodic migraine, the fundamental therapeutic strategy is prevention. This narrative review describes how to try to prevent the development of MOH and how to manage it once it has appeared.

AREAS COVERED

A PubMed database search (from 1988 to January 2015) and a review of published studies on chronic migraine and MOH were conducted.

EXPERT OPINION

In spite of progress in migraine treatment, the prevalence of chronic headaches and MOH has not changed in the course of time. Today, a large number of migraine patients have turned to numerous expert physicians and experienced all sorts of prophylactic treatments without decisive benefits. Their condition seems to have crystallized even more as chronic and intractable. This means that to prevent chronification and MOH, we need more effective drugs and better strategies to use them. In particular, we must detect disease biomarkers and predictive factors for drug response that allow for personalized treatment when migraine is still episodic and make analgesic overuse pointless.

Pharmacokinetics and interactions of headache medications, part I: introduction, pharmacokinetics, metabolism and acute treatments

Recent progress in the treatment of primary headaches has made available specific, effective and safe medications for these disorders, which are widely spread among the general population. One of the negative consequences of this undoubtedly positive progress is the risk of drug-drug interactions. This review is the first in a two-part series on pharmacokinetic drug-drug interactions of headache medications. Part I addresses acute treatments. Part II focuses on prophylactic treatments. The overall aim of this series is to increase the awareness of physicians, either primary care providers or specialists, regarding this topic. Pharmacokinetic drug-drug interactions of major severity involving acute medications are a minority among those reported in literature. The main drug combinations to avoid are: i) NSAIDs plus drugs with a narrow therapeutic range (i.e., digoxin, methotrexate, etc.); ii) sumatriptan, rizatriptan or zolmitriptan plus monoamine oxidase inhibitors; iii) substrates and inhibitors of CYP2D6 (i.e., chlorpromazine, metoclopramide, etc.) and -3A4 (i.e., ergot derivatives, eletriptan, etc.), as well as other substrates or inhibitors of the same CYP isoenzymes. The risk of having clinically significant pharmacokinetic drug-drug interactions seems to be limited in patients with low frequency headaches, but could be higher in chronic headache sufferers with medication overuse.

Role of Organic Anion Transporting Polypeptide 2 in Pharmacokinetics of Digoxin and β-Methyldigoxin in Rats

Recently, we found that potent P-glycoprotein (P-gp) inhibitors, such as verapamil and cyclosporin A, markedly modulated the pharmacokinetics of digoxin in rats, whereas they did not affect beta-methyldigoxin pharmacokinetics significantly. Digoxin is also a substrate of rat organic anion transporting polypeptide 2 (Oatp2). Here, we compared the magnitude of Oatp2-mediated drug interaction of digoxin and beta-methyldigoxin using amiodarone as an Oatp2 inhibitor in rats. Amiodarone (20 mg/kg) given intravenously significantly increased plasma levels and decreased biliary excretion, liver distribution, and intestinal distribution of digoxin administered intravenously at a dose of 10 mug/kg. Amiodarone also significantly decreased biliary excretion and liver distribution of beta-methyldigoxin, but the change in plasma levels of beta-methyldigoxin was quite small. These findings may give a clue in selecting these cardiac glycosides in clinical pharmacotherapy for patients receiving multiple drugs towards escape from Oatp2-mediated drug interactions.

Differential pharmacokinetics of digoxin in elderly patients

Digoxin remains one of the most commonly prescribed of all cardiac medications. The main indications for digoxin usage include atrial fibrillation and heart failure; both these conditions are more prevalent in older patients. Given the aging population and the increasing incidence of heart failure we would expect prescribing of digoxin to remain as frequent or to even increase in older patients. Older patients are also more likely to develop toxicity and diagnosis of digoxin toxicity can be difficult in this group. Numerous components contribute to the development of toxicity in older patients, ranging from aging-related changes in renal function or body mass to polypharmacy and possible interactions with digoxin. It is therefore important to understand how the pharmacokinetics of digoxin may be altered in the older population. Application of basic pharmacological principles may be helpful in anticipating these problems. This review describes the pharmacokinetics of digoxin, the changes in pharmacokinetics with increasing age and how concomitant disease states or drug interactions may affect the pharmacokinetics of digoxin. Greater knowledge about the causes and prevention of digoxin toxicity should further reduce the morbidity and mortality arising from digoxin toxicity, especially in the elderly population.

The effect of meloxicam on the pharmacokinetics of beta-acetyl-digoxin

The influence of multiple-dose administration of meloxicam on the pharmacokinetics of oral beta-acetyl-digoxin was studied in 12 healthy male volunteers in a randomized double-blind two-way crossover study. The primary endpoint, Cminss, was within the accepted range for bioequivalence, as were Cmaxss and AUCss. The 90% confidence interval and the point estimator of 98.7 for Cminss were within the equivalence range of 0.8-1.25. MRT and tmax were also unchanged, while the elimination rate constant was decreased slightly by 12%, which is of no therapeutic relevance. It is concluded that co-treatment with meloxicam has no effect on the pharmacokinetics of oral digoxin.

Cardiac glycosides. Drug interactions of clinical significance

Several commonly coadministered drugs interfere significantly with the pharmacokinetics or pharmacodynamics of cardiac glycosides. Only a few of these interactions (e.g. amiodarone, propafenone, quinidine) take place consistently, and although their extent may vary in individual patients, digitalis dosage adjustments should be made to avoid underdigitalization or toxicity. In other instances the appearance of clinically significant interactions depends on individual pharmacokinetic/metabolic characteristics (e.g. erythromycin, tetracycline), and the result cannot be anticipated on clinical grounds. Some interactions are controversial, having not been confirmed by all studies; others have been shown only in healthy volunteers but lack the definition of their relevance in the context of disease states. In view of the possible impact on the individual patient, close clinical monitoring (which may be supplemented with evaluation of digitalis plasma concentration) is recommended when prescribing cardiac glycosides with other therapeutic agents for which the possibility of an interaction has been reported.

Pharmacokinetic-pharmacodynamic drug interactions with nonsteroidal anti-inflammatory drugs

The nonsteroidal anti-inflammatory drugs (NSAIDs) are very commonly prescribed, especially in the elderly population. In many countries more than 10 different NSAIDs are available. As the older pyrazole compounds like phenylbutazone, oxyphenbutazone and azapropazone are most prone to pharmacokinetic interactions, the use of these compounds should be avoided where possible. Acidic NSAIDs interact with bile acid-binding resins, resulting in decreased concentrations of NSAIDs in the blood. In earlier reports it was suggested that the absorption of NSAIDs was affected by antacids and sucralfate. More recently, it was shown that there is delayed absorption of these drugs, but there is no difference in the extent of absorption. Only salicylates had their urinary secretion enhanced by antacids, which increase the urinary pH to values > 7. Histamine H2-receptor antagonists can be combined safely with NSAIDs. The concomitant administration of probenecid increased the blood concentration of NSAIDs, so an enhanced anti-inflammatory effect can be expected when these 2 drugs are combined. More importantly, NSAIDs can cause pharmacokinetic drug-drug interactions with other drugs. As can be expected, interactions with drugs that have a small therapeutic window are most likely to be of clinical significance. For example, lithium, medium to high dose methotrexate and, to a lesser extent, cyclosporin may be affected by concomitant administration of an NSAID. Aspirin (acetylsalicylic acid) and/or pyrazoles interact with oral anticoagulants, oral antihyperglycaemic agents and the anticonvulsants phenytoin and valproic acid (sodium valproate). Elevation of blood concentrations of these agents can be potentially dangerous. Similarly, NSAIDs interact with digoxin. This interaction is most likely to occur in the elderly, in neonates or in patients with renal impairment. Indomethacin can influence the blood concentrations of aminoglycosides in neonates. Unfortunately, this effect seems unpredictable, so practical therapeutic recommendations cannot be made. When NSAIDs are combined with salicylates or diflunisal, the blood concentrations of the salicylate or diflunisal may increase. However, the clinical relevance of this increase in drug concentration seems to be of minor importance. Gastrointestinal bleeding caused by NSAIDs is the most dangerous when it results from a mixed pharmacokinetic/pharmacodynamic interaction; however, patients are also at risk when pharmacodynamic interactions only are involved.

Adverse drug interactions with nonsteroidal anti-inflammatory drugs (NSAIDs). Recognition, management and avoidance

The prevalence and incidence of adverse drug interactions involving nonsteroidal anti-inflammatory drugs (NSAIDs) remains unknown. To identify those proposed drug interactions of greatest clinical significance, it is appropriate to focus on interactions between commonly used and/or commonly coprescribed drugs, interactions for which there are numerous well documented case reports in reputable journals, interactions validated by well designed in vivo human studies and those affecting high-risk drugs and/or high-risk patients. While most interactions between NSAIDs and other drugs are pharmacokinetic, NSAID-related pharmacodynamic interactions may be considerably more important in the clinical context, and prescriber ignorance is likely to be a major determinant of many adverse drug interactions. Prescribing NSAIDs is relatively contraindicated for patients on oral anticoagulants due to the risk of haemorrhage, and for patients taking high-dose methotrexate due to the dangers of bone marrow toxicity, renal failure and hepatic dysfunction. Combination NSAID therapy cannot be justified as toxicity may be increased without any improvement in efficacy. Where lithium or anti-hypertensives are coprescribed with NSAIDs, close monitoring is mandatory for lithium toxicity and hypertension, respectively, and aspirin (acetylsalicylic acid) or sulindac are preferred. Phenytoin or oral hypoglycaemic agents may be administered with NSAIDs other than pyrazoles and salicylates provided that patients are monitored carefully at the initiation and cessation of NSAID treatment. Digoxin, aminoglycosides and probenecid may be coprescribed with NSAIDs, but close monitoring is required, particularly for high-risk patients such as the elderly. Indomethacin and triamterene should be avoided due to the risk of renal failure. High dose aspirin should be replaced by naproxen in patients on valproic acid (sodium valproate) and care is required when corticosteroids are administered to patients taking salicylates long term in high dosage. Interactions between NSAIDs and antacids or cholestyramine are generally avoidable. Adverse drug interactions involving NSAIDs may be limited by rational prescribing and by careful monitoring, particularly for high-risk patients, drugs and therapy periods.

Clinical use of serum digoxin concentrations

The development of the radioimmunoassay for digoxin by Smith and coworkers in 1969 was a landmark in digitalis therapy. Since then, the complex pharmacokinetics of digoxin have been defined. As a result, the incidence of digitalis toxicity has markedly decreased. To use the digoxin assay properly, however, the relation of this pharmacokinetic parameter to digoxin pharmacodynamics must be known and the limitations of the assay itself understood. Systolic time intervals (STI) are uniquely useful to quantitate the inotropic effect of digitalis preparations. This technique can demonstrate the onset and magnitude of the inotropic effect for both oral and intravenous digitalis administration. By defining the mathematical relation between STI and simultaneous serum digoxin concentrations following intravenous administration of 1 mg digoxin, computer simulations can be made of the effect of dosing changes on blood and tissue concentrations. The serum digoxin assay has technical problems relating to quality control, interference by metabolites, and cross-reactions with endogenous digitalis-like substances. Further, a standard time for measurement following dosing has not been established. Physical activity can significantly after the serum digoxin concentrations by increasing skeletal muscle binding. Numerous drugs can interfere with digoxin absorption or elimination. Using the serum digoxin assay is the only way to assess these interactions. Computer surveillance (ideally with physician or pharmacist interaction) has been used to monitor digitalis but has not yet gained widespread acceptance. This is clearly a method in need of further testing.